Traci Mann: “Eating Lab: The Science of Weight Loss” | Talks at Google


FEMALE SPEAKER: Hi everyone. Thank you for coming. I’d like to introduce Dr. Traci
Mann, a professor at UCLA, here to talk about her book,
“Secrets From the Eating Lab.” TRACI MANN: Thank you so much. I’m very happy to be here. Thank you all for coming here. I know it’s Monday, the
beginning of the work week. You probably have your
head somewhere else. I appreciate you coming here
right now to hear from me. I’m a psychologist. And for over 20
years about, I’ve been studying the self-control
of eating, basically looking at whether people
can resist foods that are right there in front of them? And over the years, I’ve learned
what all psychologists learn quite quickly, which is that
when people ask me what I do, I have learned to never. Ever, ever say that
I’m a psychologist. People immediately assume
that I’m a therapist. I’m not– they
immediately assume that I study or know something
about psychopathology. I don’t. But they assume this
and start telling me all about their
crazy uncle or worse. Themself. So I don’t do that anymore. Now, you guys do not
have this problem. You get to tell people
that you work here. And they think that’s cool. So it’s a whole– although maybe
they get jealous and cranky and then maybe it all
goes to hell after that. I don’t know. Anyway, we all have
our own problems. You guys don’t
have that problem. Here’s how I deal with my
problem is instead of telling people I’m a
psychologist, I’ve learned to be a couple steps
more specific than that about what I do. So I say that I
run an eating lab and do research on the
self-control of eating. And whenever I tell people that,
they always say the same thing. Not that. Not that ever. [LAUGHTER] Nobody ever says that. Nobody has ever, ever, in over
20 years, said that to me. Do these people exist? I don’t know. Probably. Because as a psychologist, I
know that all kinds of people exist. But I think it’s probably rare. And, in fact, maybe some of
you are this kind of person. I don’t know. And don’t tell us if you are
because no one wants to know. No one wants to hear it. Anyway, it exists,
but it’s rare. What everybody
actually says to me– and I do mean everybody,
without exception, everybody says to me, oh man,
self-control of eating, I need help with that. I need some of that. That’s what I struggle with. And they all say it as
if they’re this unique– it’s sort of that they have
this unique struggle that most other people don’t have,
all these people thinking that they’re alone
in their inability to reliably resists foods. They’re not alone. They’re pretty much everybody. Everybody struggles with
self-control, thin people, fat people, everyone in between. Now, are you guys OK with
me using the word fat? We’re good. It’s just a word, not
a judgment in any way. No valence. It’s just a description. Because sometimes
I use that word. Sometimes I say obese. Sometimes I say fat. So I want to make
sure we’re all good. OK, so everybody
struggles with this. Now if everyone
struggles with this, it’s hard to see how this could
be the crucial factor that explains who’s
going to end up thin and who’s going to end up fat. And sure enough, there is
plenty of scientific evidence that shows that willpower,
self-control– those are the same things. I’m going to use those
words interchangeably. There’s plenty of
evidence that willpower plays a much smaller
role in people’s weight than everybody thinks. I’m going to tell you about
some of that evidence. But first, let’s just
think through a situation so that you could actually
appreciate why it probably doesn’t matter very much. So here’s the situation. Suppose you’re in a
meeting and there’s someone– one of your
coworkers comes in and plops a box of
donuts down on the table. And you’re all
sitting at this table. I’m imagining what
meetings are like. I have never actually
held a real job. So I don’t know what
meetings actually are like in the real world. Anyway, this is the
picture that I have. A big table, everyone
sitting around it. Somebody comes in with
this box of donuts. It’s great. Except that you are trying
to resist having a donut. For whatever reason, you don’t
want to be eating a donut. So you’re trying to resist it. Now, resisting this donut during
the course of this meeting is not just one simple
act of self-control. This is many, many
acts of self-control. You have to resist it now,
when they plop down the box. And you have to resist it
two minutes from now, when you look up and notice it
again, and a minute after that, and a minute after that. And you basically have to
resist it every single time you look up and
notice it, which is going to be some combination,
some sort of interaction between how exciting the meeting
is and how hungry you are. And the hungrier
you are, the more you will look up and notice it. Now if you resist this
donut the first 19 times that you look
up and notice it, but then you get distracted
by something going on in the meeting or something
else, if you get distracted, have a two-second moment of
weakness during which you take one of those donuts and
subsequently go on to eat it, if this happens, you
do not get credit for those very impressive
19 displays of self-control that you just demonstrated. You have nothing to show for it. You may as well have
had bad self-control for all the good your
impressive self-control did for you in the end. You ate the donut. But so did your friend, with
much worse self-control, who ate it on the fifth time
that they looked up and noticed it. So with eating, momentary
lapses of self-control basically erase
previous successes. And that essentially wipes out
the differences between people, except on the extremes. In the extremes, you’re still
going to see differences. But in the vast
middle, you’re not going to see a lot
of differences. Now, this is not really
true with other behaviors. So let’s think about
another behavior. Let’s think about
academic achievement, getting good grades,
doing well on tests. This requires self-control. You need to use self-control
when you’re studying for a test basically, so that you
don’t get distracted. And, of course,
this task is harder than it’s ever been
for young people. I mean we used to sit
down with a book to study. And there weren’t so
many distractions. Now, you’re studying. You’re online. It’s a click away to start
doing something else, to start answering mail,
or watching a video, whatever it is. So you’re studying for a test. Now, let’s say you have
a lapse of self-control. And instead of studying, you
stop and you do whatever. You watch some videos. Maybe this costs you a
few minutes of studying. Maybe it costs you five
minutes of studying, maybe 10. That’s not great. But, importantly,
what it didn’t do was erase all of the studying
that had come before. All the studying you did up
until that point is still there. It’s still in the bank. Your lapse of self-control
didn’t undo it, the way it does with eating. So eating is uniquely
unforgiving of lapses in self-control. And then to make matters
worse, lapses in self-control are also extremely
hard to avoid when it comes to eating because we
have too many opportunities. There’s food all
around, everywhere. There’s too many
temptations all around us. It’s certainly true
here in your workplace. And temptation is everywhere. And lapses, it’s too
easy for them to happen. And they happen so quickly. There’s always enough time to
have a lapse in self-control when it comes to eating. So willpower would have to
be incredibly strong, nearly flawless to handle that. But it’s not. It’s actually the opposite. Willpower is fragile. It’s fragile. And it’s really easy to disrupt. So for years, all these years
of my lab doing studies, where we put milkshakes
in front of dieters with the goal of
looking at what would help them to resist a milkshake
and what would mess them up? And basically,
everything messed them up and nothing helped them. And you say it’s really fragile. Another problem
with willpower is that despite what
you probably have seen on the cover of
magazines, depending on if you look at
this sort of magazine, there is no evidence
at all that people can harness their willpower. I’m actually not sure
what that even means, but I know that
it’s not possible. If that’s possible, to
know it’s not possible when I don’t know what it means. There’s no evidence that
you can grow your willpower or get better at it. So I promised some evidence
that willpower doesn’t matter so much for weight. So here’s some evidence. There’s a test they use
in willpower research to see how good or bad your
willpower is, how good or bad your self-control is. And this is called
the marshmallow test. And you’ve probably heard of it. It’s very well known. This is not from my own work. This is from other
people’s work, in particular Walter Michel. And you basically leave
a four-year-old kid alone with one marshmallow
and tell them that if they can resist
it, then later they can have two marshmallows. So then they just
see how long the kid can resist the one marshmallow. They actually count up
the seconds or minutes that the kid can
resist the marshmallow. It’s very difficult
for some kids, although this guy’s doing way
better than my kids ever did. No psychologist should ever
test their own kid on anything. But when my kids turned
four, I stuck them alone with a marshmallow. And I couldn’t even get out of
the room before they ate it. [LAUGHTER] And you’re about to see how
poorly this bodes for them. Sorry, guys. I shouldn’t have mentioned you. Anyway, they do the
marshmallow test. They see how long kids can
resist the marshmallow. And then they come back. So for the examples
I’m giving you, they come back 10 years later
and see how they’re doing. How long they can
resist this marshmallow predicts other outcomes
later in their life. So the two examples I’m
going to mention here are how well they do on
their SAT and their weight. And it turns out
that, first of all, willpower does predict
both of those things. So how long you can resist that
marshmallow at age four does predict each of those things. But absolutely,
importantly, willpower is way, way, way
better at predicting how well you do on the SAT
than your later weight. In fact, it’s eight times better
at predicting your SAT scores than your weight. And to say that more
precisely, because that’s not totally the right way
to say that, willpower explains 32% of the variation
between people in their SAT scores. A full third of the variation
between people and their SAT scores can be explained
by their willpower, by how well they do on
this marshmallow test. But willpower only explains 4%
of the variation between people and their weight, 4%. Willpower is supposed
to be the thing that matters the most
for people’s weight and yet it only explains 4%
of the variation in weight. 96% of the variation
in people’s weight is from something
other than willpower. Now, I did not get
overly complicated. Just forget all that. I’ll say it a different way. Here’s my simple, but
I’m not going to lie, slightly obnoxious way
of remembering just how unimportant self-control
is when it comes to weight loss or maintaining weight loss. Now to appreciate
this, you first need to realize that
diets don’t work in the long run for the
majority of dieters. So we reviewed all the
long-term studies of diet. Studies that looked
at people who went on diets and followed them for
at least two or more years. And what we found is
that by about three years after starting a diet,
the average dieter has regained everything
they lost, but two pounds. So basically, they’ve
gained it all back. So diets don’t work in the long
run for the majority of people. And I’ve seen the number 5%
as the percent of dieters who actually keep weight
off in the long term or keep a lot of weight
off in the long term. So the minority
of people do that. Now, here’s how you
know self-control doesn’t matter all that much
when it comes to weight. There’s a person who is
in this special minority of 5%, this 5% of people who
have taken off a lot of weight and kept it off. And that person is Bill Clinton. He became a vegan. He lost a bunch of
weight and kept it off for a very long time. That’s great. Go Bill. I’m a fan. I voted for him. But this is not a
person who most of us associate with having
good self-control. [LAUGHTER] He’s known– and I
hate to say this. I’m told it’s going
on the internet. But this is a man
whose trademark is that he had no self-control. That’s his thing. But it doesn’t matter. Because self-control is
only slightly related to weight and weight loss. If you’ve struggled
to take off weight, if you’ve struggled to keep
off weight that you lost, it is not because you have worse
willpower than everybody else. It’s not because you
have a weaker will. It’s not because you
have less self-control. I’m saying that over and over
in lots of different ways because it’s an important point
that I want people to remember. If you can’t keep weight off,
it’s not because you’re weak. It’s not. So what is it because of? Well, before I answer that,
let me ask you guys a question. Do any of you know someone you
can just eat whatever they want and not get fat? Right, you do. Let the record show people
are all nodding or raising their hands. We all know people like this. And they don’t even
exercise, right? And you’ve probably
never even thought about what that means,
aside from the fact that there is truly no
justice in the world. But aside from that, you’ve
probably never thought about what that means. Some of you might even be the
person that I’m describing. And again, keep it to yourself. Don’t share it. Don’t share it with the
room, just a little pointer. Now you know what else exists
is fat people, who don’t eat that much but are still fat. For the longest time,
obesity researchers just flat-out denied that
this kind of person existed. When they did studies where they
had people record everything they ate for days, or
weeks, or months even, they’d find plenty
of fat people who weren’t eating all that much. The majority weren’t
eating a lot, weren’t eating a ton of food
the way people would assume. And they would also
find fat people in their studies eating
even less than some of the thin people
in their studies. Now when obesity
researchers were faced with that kind of
evidence, what they concluded is that the fat
people were lying. We’re so, so, so harsh,
just outrageously harsh, just above crazy, crazy. They’re not lying. The lie is the thing that we’ve
all been taught is the gospel. The lie is that
anyone can get skinny. And all you need
to do to get skinny is to exercise off more
calories than you eat. We’ve all been told that. But if that were
true, how could we have thin people who eat
so much and never exercise without getting fat? How could that exist? It does exist. How could it if that were true? We couldn’t have fat people
who don’t eat that much and stay fat. They don’t eat that
much and not get thin. It wouldn’t be possible. But these people do exist. And the reason
these things exist– the reason these people exist,
is a more appropriate way of saying that– is because
your weight is influenced by so much more than just
the calories that come in and the calories that
you burn off exercising. So I was at an academic meeting
recently, just a few weeks ago. And somebody put up
this diagram showing all the different things
that influence obesity, just a simple little
diagram, crazy, crazy diet. Luckily, they put up
the simple diagram next. Here’s their simple one. They even labeled
it “simple model.” And don’t need to pay attention
or look at this at all, other than knowing this
is the simple model. So a lot of these functions on
this little graph are genetic. Now, we know a lot about
the genetics of obesity. And originally, we
learned about it from studies of people
who were adopted. When kids are adopted, you
can compare their adult weight with the parents
who raised them, who set their eating habits,
set their eating environment. And you can compare their
weight with their birth parents, who they share genes with. And what you find is
that adopted kids, their adult weight
is much, much more highly correlated with their
birth parents, who again, never met, but they share
some genes, about 50% of their genes. Much closer to their
weight than the weight of the adoptive parents,
who again are deciding what they eat most of the time. So that suggests genes
matter more than environment for this outcome, for weight. Now, we also know a lot
from studies of twins. My university, the
University of Minnesota, is the home of twin studies. Coincidentally, it’s in
the Twin Cities, unrelated. It’s a complete coincidence. Seriously, it’s a
complete coincidence. And they originated the studies
of twins, identical twins reared apart, which if you think
about it is the perfect study. They share 100% of
their genes, but have different environments. So you can really separate
out genes from environment in that kind of study. And those kinds of studies
show the very powerful role that genetics play
in people’s weight. These are identical twins. These are not identical
twins reared apart. I don’t have pictures of those. But these are
identical twins, again sharing 100% of their genes. And you can see that
in most of the pairs, the weights are nearly
identical to each other. They’re not all identical. They’re not 100%
identical because genes don’t explain 100% of
what your weight will be. But it plays a large role. These are fraternal twins. They share 50% of their genes. And you see they’re not nearly
as similar to each other as those twins who
shared all their genes. OK, genes matter. They play an important role. Now when you say
something is genetic, people get this weird idea
that the thing is simply coded on one single gene. So with weight,
people think there’s one gene and that gene says
this person will weigh 150 pounds when they’re full grown. Clearly, that’s way too simple. In fact, there’s over
100 different genes that are linked to obesity,
that we know of currently. Every year, they’re finding
more and more genes. This graph just shows
the number of genes that they found that influence
susceptibility to obesity. And they’re finding more
and more, at quite a pace. 2013 to ’15, they
found a lot of genes. So what are these things
that are coded on genes? Well, let’s start with hormones. So the relative levels
and responsiveness of dozens of different hormones
are coded on our genes, including these hormones of the
gastrointestinal system known as the gut hormones. And there’s a
whole lot of these. So some of these hormones
determine how much you need to eat to feel full. Some determine when you’re
going to feel hungry and when you’re not
going to feel hungry. Some people might feel full
from eating one sandwich. Other people of
the same size may need to eat three
sandwiches to feel full. They may need to
eat three sandwiches before their satiety
hormone kicks in. If one sandwich fills you up,
you are less likely to overeat. And it’s because of these
genetically determined hormone differences. What are you supposed
to do if you need three sandwiches to feel full? Are you supposed to only
eat one and live hungry? Are you supposed to live
never feeling sated, never feeling full? Just consider it. Think about it later,
on your own time. If you think it’s fair
or appropriate for us as a society to expect
some people to never feel full, to
always feel hungry, just to achieve
a certain weight? I’m not sure. I’m not sure that’s OK. Now, another thing
hormones influence is which foods you like
and which foods you want, how palatable you
find different foods. If you’ve ever been pregnant,
you’ve experienced this. If you’ve ever
been pregnant, you know that this has
to do with hormones. When I was pregnant, all I
wanted to eat were apples. Apples, normally who
could care about apples? Normally, I wanted
ice cream, cookies. But when I was pregnant, I had
no interest in those things. All I wanted were apples. Hormones clearly
have something to do with that food preference. So for some people, it’s
going to be much easier to resist ice cream than
it is for other people. But it won’t be because of
their impressive self-control. They might tell you it’s
because of their self-control. But really, it’s because they
weren’t as tempted by it. It didn’t look as good to them. It’s not calling
out to them, the way it calls out to some of us. It doesn’t seem as appealing. You know how they say it
doesn’t count as bravery if you weren’t afraid to begin with? It’s the same thing. It’s not self-control
if you didn’t want the thing in the first place. That’s not self-control. That’s just a different palate. It’s just a different set of
genetically based preferences. Now you know you know
people like this, of course. You’ll be in a
restaurant with them. And when it’s time to order
dessert, they’ll say, oh, no. I could never eat
chocolate mousse. That’s just– I have people in
my own home who say I could never eat marshmallow
Peeps for breakfast. That’s crazy. Ah, that’s so annoying. OK, people, whatever. People have different
preferences. So those are
hormonal differences. And there’s also
neural differences, neurological differences. So people differ in their
brain’s responsiveness to the sight of food and to
the sight of different foods. So some people get a
big reward response from seeing or eating food. They get a big rush of dopamine. Now you guys know
about dopamine, right? It’s this neurotransmitter
associated with reward, with pleasure, with addiction. People get a big dopamine rush
from drugs they’re addicted to. So some people get a
bigger dopamine rush from certain foods
than other people. So the bigger this response,
the bigger the reward response, the more pleasing you
find it to have this food. The more you crave this
food, the more difficult it’s going to be for you to
resist it, if it’s present. There’s a lot of different
neurological functions that influence people’s
susceptibility to obesity. I’m literally just naming
that one, the reward response. There’s others too. Actually, we’ll mention
another one in a second. So neurological responses to
foods have a genetic basis. And then metabolism– and,
of course, your metabolism is genetically based. And you guys all know
about metabolism. Your metabolism determines
how efficiently you use the calories that come in. And it determines
how many calories you burn just doing
the job of running the systems of your body. So some people are going to
burn up more of the calories from that donut
than other people, just while sitting still. And this is how you can
have people who eat a lot and remain thin and people who
are fat, who don’t eat a lot. You can put people
on the same diet and completely different things
will happen to their weight. So this is a graph
that shows what happened to 29
different people, who were put on the exact same, very
low-calorie diet for 10 weeks. This is their weight change
in terms of the percent of their starting weight. So each bar is a
different person. And what you can see is
that different things happen for different people. Some lost a lot of weight,
some lost a little weight, and some gained weight. When you see graphs
like this, people say, well, I bet
some of those people lied and ate more than
they were supposed to. And certainly, this is
possible on any diet study, for the most part. But they’ve also done studies
where the person checks into the researcher’s clinic,
to a diet clinic, to a hospital, whatever it is. And they live there for
the duration of the diet. And they only eat the food
the researchers give them. And you still get
this wide variation in what happens to people. Now, the same is also
true for overeating. So this next graph is from a
study where researchers first figured out the exact
number of calories to give people so that their
weight would stay the same. So they figured that out. And then they
overfed each of them a thousand more calories
per day for a hundred days. And they didn’t allow
them to exercise. So each– by now, it’s like
who is volunteering here? Again, each bar is
a different person. And again, you see
this big variation. Some people gained as much
as 30 pounds in the 100 days. Some gained as
this little as 10. And– not that we’re going
to talk about exercise today exactly. But the same thing is
also true for exercise. And this graph is from an
exercise study, where everyone did the same intensity
exercise for 12 weeks in the
researcher’s clinic, in front of the researchers. And some people lost a lot of
weight, some lost a little, and some gained. And the reason there’s
two colored bars is because one is their weight
and one is their fat mass. Either way, the
same point is made, whichever one you look at. So first point, your weight
is based on a lot more than calories in, calories out. And genetically-based factors
affect so many aspects of it, including things like
how tempting a food looks to you, how rewarding that food
is to you, how much you crave it, how hungry you feel
after eating the same food, and the rate at
which you burn up the calories from
that same food. If you’re a thin
person, you’re probably on the lucky side of a lot of
those, if not all of those. You’re probably on the side that
makes it easy to resist food, makes it easy to burn calories,
makes it easy to remain thin. If you’re a fat person,
if you’re an obese person, odds are you’re on
the other side of that, the side that
makes it difficult. It seems crazy to blame
people for their fatness or be impressed
by their thinness. It is way less about
them than it seems. OK. So that was point one. Now, point two is where–
and there’s only two points. Point two is where
things get really frustrating because regardless
of where you start out on these biological factors
here, regardless of where your genes put you, there is
one thing that reliably messes these things up for everybody. And that one thing is dieting. And so if you restrict
your eating for a while and lose some
weight, if your body detects that not enough
calories are coming in, all of these biological
factors change for the worse. They change in the way
that undermines your effort to keep weight off. And this is why diets
don’t work in the long run for the large
majority of people. So after losing
weight, your metabolism changes so that you run
your body on fewer calories than before, leaving more left
over, unused, to store as fat. So if you eat the same
amount of calories that you were eating when
you lost weight on your diet, after a while you’ll
stop losing weight. You might even start
gaining weight. They sometimes call
this the plateau. And what will people say? They’ll say you had
no self-control. They’ll say you
couldn’t hack it. You couldn’t do it. You were weak. Even though you’re eating
so little, and probably even eating less than they’re eating,
if they’re not on a diet. So that’s metabolism. After losing weight, your
hormone levels change. So you’re more likely
to feel hungry. You need to eat more
to feel full than you than you used to,
than before dieting. So if you eat the same
amount of calories you ate to lose
weight, you’re going to feel even hungrier
than you felt then. You probably felt hungry
then because you weren’t eating that many calories. Now, you’re even hungrier. To keep weight off, you
have to always be hungry. After losing weight,
also your brain changes. It changes in ways that
make food more tempting. And you become
preoccupied with food. And there’s all kinds
of evidence for this. But the earliest kind
of evidence for this, and the kind that I think
is the most fun is– OK, that’s going to
seem inappropriate. But it is the kind that
you find in journals that explorers leave. Explorers are actually
convenient people to study when it comes to
the effects of starvation because, unfortunately,
explorers do two things. One is that they keep journals,
where they’re very precise. And another is that
they die of starvation. So you can read their journals
and learn a lot from them. And what you find is they
talk about food a lot. They mention
dreaming about food. They write about
their favorite meals. They write about what the
first thing they want to eat is when they get home, all this. This guy, this slide
is Robert Falcon Scott. He’s a polar explorer. And I feel like– he’s
not so famous in the US. He’s extremely
famous in England. He’s British. And the reason he’s not so
famous outside of England, outside of his home, is
because he came in second. And coming in second,
for an explorer, it’s like not exploring at all. It’s either you’re the first
one there or you’re not. And you discovered
it or you didn’t. His team unfortunately got
beaten to the South Pole by 28 days. And unfortunately, also,
they died on their way back. They starved/froze to death. Polar exploring is insane. I mean– it’s–
yeah, yeah, anyway. I’m an indoor person– so maybe. It just seems really
extremely extra crazy to me. Anyway, Scott’s
journal– and there’s a whole museum devoted
to him in Cambridge. This is where I
was on sabbatical. And it’s fun to
read his diaries. I mean– OK, again,
it sounds horrible. They’re fascinating. It’s not grisly. It’s just a very
interesting thing. He’s extremely tough
and not whining in any sense of the word. Anyway, you don’t
have to be starving to death for these
neurological changes to happen. They happen when you
lose weight, even just a little weight. They happen when you’re
depriving yourself of food. And what happens is– and
every dieter will tell you this happens. You think about food constantly. You’re more likely to
notice it if it’s there. And eating food gives you an
even stronger reward response than before dieting. And this is not ideal, if
you’re trying to keep dieting. OK. So point two is
that dieting leads to biological changes that make
it incredibly difficult to keep weight off. Just that small minority
of people manage to do it. And to do it, they have to go
about their lives basically devoted to this, devoted to
eating very, very little, to always feeling hungry, and
constantly thinking about food. Basically fighting against all
of these things in these red bubbles here. Now, knowing about these things
makes me just screaming mad when people blame dieters for
regaining weight they lost. I just– ugh. I cannot take it
when people say– and this is the thing that
people are constantly saying or putting in comments when
I talk at other places. They say, well,
they’re in the end, they’re still the one holding
the fork and shoveling it in. It just makes me absolutely
want to throttle them. Yes, I will give them this. They are holding the fork. I will give them that. Yes, it’s true. But they are holding that
fork in a completely different physiological
context than someone who hasn’t been dieting. In this context,
they’re holding the fork in a context in which their
biology has turned on them. And to succeed, they have
to battle against all these biological factors. So if you’ve been
dieting, you hold the fork in a context in which your
hormones are preventing you from feeling full and
causing you to feel hungry, to feel extremely hungry,
no matter what you eat. You’re holding the
fork in a context in which your brain is more
likely to notice foods, if they’re there. It pays extreme attention
to thoughts of food and can’t really be shaken from
those thoughts very easily. And you hold the fork in the
context in which your brain is responding to food,
with a bigger, more powerful hit of
reward, with extra pleasure and extra reinforcement. So, yes, fine, that
they held the fork. But it’s this
physiological situation that made them so
likely to pick it up. So I thought this
information was something people
should know, something that people should hear about. So 11 years ago, I
wrote a book proposal about why diets don’t work. And no publisher
would come near it. They did not want a book that
started with the three words, diets don’t work. They just said that is too
bad, that is too negative, that’s too much bad news. Nobody wants to read bad news. No one’s going to read bad news. Forget it. And this absolutely
drove me nuts. Because first of all, I
don’t think it’s bad news. I don’t think it’s
bad news to learn that it’s not your fault if
you gain weight, that it’s not your fault if you
find it difficult. That it’s not
because you’re weak. It’s not a personal failing. It’s because you are a
biological human being. Now secondly, people deserve
and want to know what’s true. I fully believe this, whether
or not it’s good news. Whether or not they’re
going to interpret it as positive or
negative, people still want to know what’s true. And they should have
the right to hear it. And they should have access to
accurate information about it. Very hard to get accurate
information about diets out there. So tons of information
is out there. But most of it is designed to
sell you something, generally a diet. So you’re not getting accurate
information about diets. It seems that this is something
people should have access to. And the thing that drove me
the most bonkers at the time is that the book that was on
top of the bestseller list, at the time that I was being
told that people don’t want to read bad news, was
a book that I think is like the ultimate
in bad news. Anyone guess what
that book might have been, bestseller
10 or so years ago, super-bad news right
there in the title? No. My husband guessed
“Tuesdays with Morrie,” which is incorrect. It’s this book, “He’s
Just Not That into You.” Come on. That is the worst news. Jeez, very annoying, but
also extremely disappointing. The only reason I was
eventually able to publish this book at all is that
for the last 10 years, I gave up on willpower. I gave up on self-control. And instead, I started
researching strategies for healthy eating that
don’t involve willpower and that don’t involve
dieting, ways to get you to eat more healthy stuff. And the goal of all these
strategies– and I’ll tell you two of them– and
the goal of these strategies is to help you reach
what I’m going to call your leanest livable weight. This is the weight at the lower
end of your set weight range. You do have a set
range of weights, that’s basically
biologically determined, that your body basically
tries to keep you within. Your leanest livable
weight will be at the low end of that
range, rather than below it. This is the lowest weight you
can be without setting off all those biological changes,
from the red bubbles, that dieting causes. Those changes, again
they happen when you try to live below
that set weight range. So aim to stay within it,
but at the low end of it. Now, this might not be as
low as your usual diet goal. This might not be the same
as your ideal goal weight. But I want to encourage
people to think of that as the best
weight for them and to aim for that weight. Because that’s a
weight you can maintain without it taking
over your life, if you do some healthy stuff. And it’s a weight that
you can be healthy at. You don’t have to get skinny
to be healthy, absolutely not. You can be healthy
at any weight. So we need something between
this damaging restrictive dieting, that’s
always encouraged, and just kind of
letting everything go. And so this is
what I’m proposing to be in the sensible middle. So I’m going to end
just by telling you about a couple strategies. OK. So some of the
strategies basically are trying to take
advantage of obstacles. There are ways to put obstacles
between you and tempting food. And these strategies work
extremely well because we– and by we, I mean humans. We tend to be lazy. I’m not going to lie. We tend to be lazy. So obstacles usually slow us
down, if not stop us entirely. So, for example, there’s a study
from the Netherlands where they show that if you have
a bowl of M&M’s– oh, if you have a bowl of M&M’s
across the room from where you’re sitting, you’re not going
to eat as many as if the bowl is right there next
to you at the table. If it’s five feet across the
room, you won’t eat as many. You’ll eat half as
many, having to get up to stop what you’re doing. You have to get up. You have to walk
across the room. That’s a giant obstacle. It turns out you don’t
need such a big obstacle to cut in half the
amount of M&M’s you need. That same study also
tested a smaller obstacle. They put the bowl of M&M’s,
instead of right here by your hand, they
put it so that you had to reach two feet
across the table for it. You basically had
to extend your arm. And if you had to lean forward
a little and extend your arm, you ate just as few as if it
was fully across the room. So this little change
made a huge difference, as much of a difference again
as actually stopping what you’re doing and getting up. Does this keep you from
eating any M&Ms at all? No. But it helps you eat a lot less. And eating less seems
like a really good goal, eating less, but not none. None, come on. People need to enjoy their life. I think anything saying
you have to have none is not going to work out. And, in fact, I’ve
done research on this with my collaborator, Andrew
Ward, years and years and years ago. We forbade our subjects from
eating a particular food for three weeks,
just three weeks. And we found that they
thought about that food more and desired that food more
than if we hadn’t forbade them. But here’s the crucial thing, we
purposely had them pick a food that they felt neutral about. Not something they loved,
not something they hated, something right there in
the, eh, in that middle area. And still, they thought
about it all the time and wanted it so much. Imagine if you’re
restricting yourself or you’re forbidding
yourself from eating something you really love? It backfires. Actually, Google did a variant
of this strategy– I actually mention this in the book. And you guys probably know
about it– with their M&Ms. They used to have M&Ms all over
the place in glass canisters. And at some point, they switched
them to opaque canisters, just to put one more step
between you and those M&Ms, just to remove one
more bit of temptation. M&M consumption went way
down after they did that. So good work, Google. Bravo. But they still have M&Ms.
Well, I didn’t see any. Maybe they’re here. I had Twizzlers, something lean. Yeah. [LAUGHTER] OK. I was happy about that. So that’s one kind of strategy. Now another kind of
strategy just flips that one around to help
you eat more healthy food by removing obstacles that
come between you and them. So removing obstacles between
you and healthy stuff. So here’s an obstacle to eating
vegetables, a big obstacle. For most people,
especially children, vegetables lose to other foods. Most people don’t think of
them as yummy as other foods. So they lose when they’re put
in head-to-head competition, like they are on every
plate ever, anywhere. That’s a competition
a vegetable will lose. Here’s a competition a vegetable
can win, some of the time. OK, nothing. Vegetable versus nothing, they
do sometimes beat nothing. And this strategy, we’ve tested. It’s what I call get
alone with a vegetable. And it’s just as easy as this. Eat a vegetable before you put
any other food on your plate. Or no, no don’t do that. Ugh. Eat a vegetable while there
is no other food in sight. If all you have is a
vegetable and you’re hungry, you’ll eat the vegetable. But put it on the plate
next to the spaghetti and all bets are off. I actually got the idea for
this from watching my kids when they were age three and six. We were in a restaurant,
a deli, which would normally come and put a
bowl of pickles on the table. You’ve been to places like this. That one day, they were
out of pickles I guess. Instead, they brought
a bowl of sauerkraut, a large bowl of sauerkraut,
which I think is disgusting. And I like most things. And apologies, foods are
culturally linked and what-not. I don’t want to insult
anyone’s culture. Actually, I have Eastern
European relatives. It’s my culture too. In any case, I think it’s
a hard sell for children. OK, fair enough? No one’s hurt or
offended by this. My kids, again aged
three and six, gobbled up an entire big bowl of
sauerkraut, with their fingers, before I could even
turn them against it by giving my opinion of it. And disgusting too,
use a fork people. Jesus. God. There wasn’t a fork. In any case, this
works with children. We tested it with children. My University of Minnesota
colleagues and I, we tested this in elementary
school cafeterias. We just gave each student a
little cup of baby carrots before they went
to the cafeteria and went in and got all their
food and sat down with it. Normally, in this school
district, only about 10% of the kids were eating
vegetables at any given meal. But once we used this strategy,
five times as many kids ate the carrots. This is extremely
effective with children. And then I also tested
it with the girls in my freshman seminar
at the U of M last fall. We had them try this
for three weeks, just to eat a vegetable
first before they got the rest of their tray of food. And they ate more
vegetables in that time. But not only that, they
also ate fewer calories in that same time period, even
though they weren’t trying to reduce their calories. They were only trying
to eat more vegetables. But it helps. Because eating vegetables,
if you eat more of them, you’re going to eat
less of something else, generally, maybe not always. So there’s two strategies. There’s 12 in the book. I’m just giving you two of them. So the key to all
of these strategies, including the other ones, is
that they don’t have anything to do with dieting or willpower. They will work, no matter how
little willpower you have. They’ll work for all of us,
with all our crappy willpower. And what I recommend, what
I hope people will do, what I think is a sensible
solution to the craziness of the pressures for
the extreme dieting and the also inappropriate,
just do anything you want, I think a sensible
middle ground is to make these simple changes,
these sorts of strategies. And then get on with that. And by doing that, you can reach
your leanest livable weight. You will be healthy
at that weight. You’ll feel better
about yourself and stop worrying
about your weight. Get weight back to
where it belongs, which is one of the more
minor things you think about or worry about. And not this giant thing in
your face, that causes so much torture to so many people. So what I’m hoping
is that people feel liberated by the message in
this book and not discouraged. Because even though it
starts with the three worst words, apparently, the three bad
news words, diets don’t work, it does end with those
really most cheerful words in the whole English
language, if you ask me, which of these three
words, cup or cone. You can’t get more
cheerful than that. And since I’m here at
Google, and I love Google, I thought I would
let Google have the last word on this topic. So I typed in dieting is not. And Google came back with
dieting is not working; not a piece of cake; not good;
and absolutely, definitely not the answer. So Google knows all. [LAUGHTER] So thank you Google. And thank you guys
for having me. I will answer any kind of
crazy question you want to ask. Or a serious one, whatever,
I’m good, anything you want. [APPLAUSE] What have we got there? AUDIENCE: I have a
small technical question about how you got the 4 and the
32% variation that explains. Is it like a simple linear
model and you used the R-squared or something? TRACI MANN: So that came
from– I have the citations in the Notes section. It came from a study– I want to
say by Walter Michel and Angela Duckworth, where they
looked at this very thing. And exactly looked
at the correlations between the seconds they
could resist the marshmallow and then their SAT
score or their weight. And they controlled for various
obvious confounding variables. And this was the
remaining correlation. And then I just
converted the correlation to the percent of variance
because it’s like people understand that more. I don’t know, maybe not. Maybe people would have
preferred a correlation. But, yeah, that’s
where it came from. So just directly off of
their published studies. They don’t describe it
that way in their studies. AUDIENCE: What’s your opinion
on strategies like drink water before, if you want
to lose weight; after, if you want to gain weight? TRACI MANN: Oh, I haven’t
heard the drink water after, if you want to gain weight. Wow. How does that– I don’t know. I don’t know how that works. AUDIENCE: [INAUDIBLE]. TRACI MANN: Ah. I mean if you fill yourself up
before a meal with some water and that helps you to
eat less, if you’re prone to eating too much
of something unhealthy, I don’t think having a little
water is going to hurt you. I’m OK with that. Yeah. It seems– I’m on-board. Yeah. I just don’t want
people to focus so much on the number on the scale. Yeah. But that seems like a
reasonable healthy to do. AUDIENCE: So what’s a
good way to figure out your range, like your
healthy weight range? Is it just when you start to
plateau using healthy weight loss methods or what? TRACI MANN: Oh, yeah. That’s a good way to look at. OK, so that’s the– I
get this question a lot. And it’s, I think, the
hardest question to answer scientifically because
there’s not research on this that I’ve seen about
how to nail in on this. So what it seems to me,
what I sort of concluded by talking to lots
of people about this, is the middle of your
sort of set range is going to be the
weight, it’s going to be the thing you weigh
when you’ve eaten reasonably, without dieting, but
without binge eating. So you’ve eaten, like, a really
kind of basic amount of food. And you’ve not been
totally sedentary. But you haven’t, like,
just won a race either. So you know what I mean? So you’re really in the
middle of all these behaviors that we know we’re
supposed to do. And that’s going to kind of
be the middle of your range. And another way
people notice this is it’s the weight that you
keep seeming to come back to. You just keep going back there. So whatever you do, suddenly
you’re back there again. Oh, really? Am I here again? And then you can use
these healthy strategies to go 10 pounds
less or whatever, depending on how much you
weighed to begin with. Yeah. Exactly. But I can’t point at like a
scientific, like, calculation that you can use to get there. That would be cool, though. But, yeah, that doesn’t exist. AUDIENCE: So thanks for coming. But just to be clear,
my lack of willpower is not the primary reason
why my weight fluctuates is what you’re saying
or my current weight is the way it is? Is that like– just so
I can tell my wife that. TRACI MANN: It’s not– Right. Definitely. AUDIENCE: No. In all seriousness,
like I remember high school I was–
for all of high school, I was probably like 160. And then university hit,
like that the freshman 15, I just went to, like, 180– TRACI MANN: Yeah. You’re giant. AUDIENCE: –and stayed there. Yeah. I’m a giant, I know. TRACI MANN: That’s a huge
human who’s talking now. AUDIENCE: But I stayed
there for the longest time, even though I tried to
do all these things. So how does your
theory explain– is it just my hormones
changed in university. Therefore, like, I’m now
stuck at this new plateau, kind of thing? TRACI MANN: So,
yeah, the research has showed that–
you see lots of diets out there that say they’re the
change your set point diet. I’ve seen this exact thing. There’s absolutely
no evidence that you can lower your set point. But, unfortunately,
there is some evidence that it can creep upward,
does this slowly over time, with large life changes,
such as going off to college, when you change your
eating habits in a big way. Lots of people, when
they get married, have very big changes
in their eating habits. And you see it creeping upward. Women, during
menopause, same thing. You see this creep upward. So it can creep. AUDIENCE: And then, just to
follow up on her question, how long should you do this,
trying of figure out your set point or set range? Like how long you have
to eat healthy and not binge eat, and– TRACI MANN: A
healthy, healthyish. AUDIENCE: –diet? TRACI MANN: I don’t know. Again, there’s not a
clear science to that. So I’m going to pull a number
out of the sky for you. Would you like me to? AUDIENCE: Yes. TRACI MANN: Let’s say,
how about a month? How about a month? That sounds about right, right? If you do– yeah,
maybe a couple weeks, three weeks,
something like that. Definitely not a
huge amount of time. AUDIENCE: Thank you. TRACI MANN: Please? AUDIENCE: Did you
look at the psychology of stress and how some people
eat when they’re stressed– TRACI MANN: Yes. AUDIENCE: –and
some people can’t eat when they’re stressed? TRACI MANN: It’s true. So emotional eating is a big
issue in the dieting world. So there’s a couple of
different things about stress. One is that I’ve done research
with my former student, Janet Tomiyama, where we found
that dieting itself causes a physiological
stress response in your body. This could be another
reason why diets don’t lead to long-term weight loss. So stress is clearly a problem. What it looks like
is that the people who eat in response
to stress tend to be dieters, people
trying to not eat. People trying not to
overeat are the ones who eat in response to the stress. Whereas people who aren’t
worrying about their eating are the ones who eat less
when they’re stressed. So what it looks like to us is
that stress messes up diets. Dieters are more likely to
overeat in response to stress. And stress messes things up. So removing stress is a good,
important strategy for– well, for overall health. I mean stress is
extremely bad for you regardless of whether
or not you’re dieting. So removing stress
is an important part of being a healthy person. And it will also help
you not gain weight. I’ll say one more thing about
emotional eating, if I may, which is about
eating comfort food. This is the strangest thing
we ever found in our research. Is that eating comfort food
doesn’t do anything special for your mood. It doesn’t do anything
different for your mood than eating any other food. And it doesn’t do anything
different for your mood than not eating food. We tested it in all these
different comparisons and it didn’t matter. Everything, even time,
made your mood slowly creep upward after we– first,
we messed up people’s moods. And then we looked at what– [LAUGHTER] This is how you have to do it. And then we looked at what
happened when we gave them either their own
personal comfort food, or a neutral
food, or a food that they like just as
much as their comfort food, or no food at all. And in every case,
their mood improved. But the comfort food didn’t
make it improve more. So because of this
I’ve come to believe that comfort food is
the thing that you crave when you’re feeling bad. It’s the thing you want
when you’re feeling bad. But it doesn’t actually do
anything special for you. And maybe you think it does
because when you eat it, you feel better. But you don’t realize, you
don’t have the control group in your head, which is
if you hadn’t eaten it, you’d have felt better too or
if you eaten something else, you’d have felt better too. So we encourage people to not
reach for their comfort food when they’re feeling
bad, thinking that it’s going to
make them better in some special, extra way. It’s not. I would say save
the comfort food, save that particular food,
for when you’re happy and can really enjoy
and appreciate it. But you don’t really need an
excuse to eat those foods. You can eat them when you wish. Just don’t justify
them, thinking it’s going to make you feel
better because no, it’s not. I mean it’s not going
to make you feel worse. Don’t go there. It’s not going to do that. AUDIENCE: Hi. So I thought the twin
study– not the twin study, the adopted child study
is really interesting, how they found
that they were more like their biological
parents than the environment that they are brought up in. And I was wondering,
like, when they compared to the biological
parents is they compared, like, with those
parents at that kid’s age? Because, like, obviously
parents are normal people too. They change– like their
set point changes over time. If, like, that
makes a difference? Because I do know
like some people– things like bone structure,
metabolism, like that, that’s all influenced by
your parents and stuff. But if it was like the
parent at that child’s age or the parent at
the current age? TRACI MANN: It’s true. So those are studies done–
I want to say Sweden, but I could be wrong–
Scandinavian-type countries, that keep these amazing,
immaculate birth records. And what their studies
were able to find was that parents’
weight– when what is it, when the child is born? And then they also
went back and were able to track these
people down because of these amazing records, and
then get their current weight. So it was their
full-grown adult weight for both sets of parents. Yeah. It’s crazy. It’s so cool that
they can do that. FEMALE SPEAKER: OK. If there’s no more
questions, I’d like to thank Dr.
Mann again for coming. TRACI MANN: Thank you. FEMALE SPEAKER: Thank you so
much for being here today. TRACI MANN: Thank you. [APPLAUSE]

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