Why do we get fat?
Taubes reveals the bad nutritional science of the last century - none more damaging than the “calories-in, calories-out” model of why we get fat - and the good science that has been ignored, especially regarding insulin’s regulation of our fat tissue. He also answers key questions: Why are some people thin and others fat? What roles do exercise and genetics play in our weight? What foods should we eat or avoid?
Why do we get fat -- and what should we do about it? Conventional wisdom says eat less, move more. The problem is that this advice rarely works very well.
Gary Taubes, author of Good Calories - Bad Calories and Why We Get Fat, discusses eating 10,000 calories a day from non-fattening foods. Interviewer: Jonathan Bailor, author of the Calorie Myth.
Is there any way to lose weight?
Actually, yes. Award-winning science journalist Gary Taubes explains (finally!) why conventional diets don’t work - and what you can do to lose weight.
interview by LISA DAVIS
if obesity researchers are so smart, why are we so large? That’s the question at the heart of Gary Taubes’s new book, Why We Get Fat - and What to Do About It. After all, public health authorities have been hammering home a very simple message for the past 40 years: If you don’t want to be fat, cut the fat from your diet. And in those years, obesity rates have gone from 13 percent to 22 percent to, in the last national survey, 33 percent.
Taubes thinks he knows why: Obesity experts have gotten things just about completely backward. If you look carefully at the research, he says, fat isn’t the enemy; easily digested carbohydrates are. The very foods that we’ve been sold as diet staples - fat-free yogurt, plain baked potatoes (hold the butter), and plain pasta (hold the olive oil, sauce, and cheese) - actu ally reset our physiology to make us pack on the pounds. And the foods that we’ve been told to shun - steak, burgers, cheese, even the sour cream so carefully scraped from that potato - can help us finally lose the weight and keep our hearts healthy.
As you might imagine, Taubes has stirred controversy with his contentions. Though he’s known as an obsessive reporter and a science nerd (he studied applied physics at Harvard and aerospace engineering at Stanford and has won numerous science-writing awards), he’s been called a dangerous cherry picker of data - someone who searches through decades of studies to weave together the bits he likes. But a series of studies in the past five years has compelled researchers to rethink their long-held prejudices against low- carb diets. These days, scientists like Mitchell Lazar, MD, who directs the diabetes institute at the University of Pennsylvania, and cardiologist Allan Sniderman, MD, at McGill University, take Taubes’s argument very seriously.
Taubes calls his ideas just an alternative hypothesis for why we get fat. Then, with trademark confidence, he adds that this radical rethinking is “almost assuredly true.” Taubes sat down with our health editor, Lisa Davis, to share the Reader’s Digest Version of his theory. Here’s what he wants you to know.
The obesity experts are wrong!
“There’s this absolutely fundamental idea when it comes to weight and obesity - that the way we get fat is that we take in more calories than we expend. It’s the gluttony and sloth hypothesis: We eat too much and exercise too little. It sounds undeniable, as commonsensical as can be, and it’s actually nonsense - it doesn’t tell us anything meaningful about why we get fat. If I get fatter, it’s obvious that I must have overeaten. But if you ask the question, Why did you overeat? Well, that question I can’t answer - not with the calories-in/calories-out theory of weight gain.
“People react to this as though I’m questioning the laws of thermo-dynamics. I’m not questioning them; I’m saying they’re not relevant. Yes, if you’re getting fatter, you’re taking in more calories than you’re burning - the question is why. There’s a ridiculously simple alternative hypothesis, which is that you don’t get fat because you’re overeating. You overeat because you’ve developed a disorder in the way your fat tissue is regulated.”
Diets don't work!
“Over the past 40 years, studies have shown that you can’t get a clinically significant effect from cutting calories. At the same time that experts are saying that gluttony and sloth are re- sponsible for weight gain, they’ll tell you that we know no diet works, and that’s why we have to come up with some anti-obesity drug that’ll make billions. That’s why the medical community considers bariatric surgery - actually altering your digestive system - a reasonable solution.
“It shouldn’t be a surprise that diets don’t work. Obese people have spent their lives trying to eat less. There are probably a few people who gave up early and said, This is hopeless and I’m going to have a good time. But for the most part, you can define an obese person as someone for whom eating less didn’t work. So the simple fact that a doctor tells you to eat less - how much good is that going to do?
“If you cut calories, you’ll be hungry all the time - that’s a given. But what also happens is that you adjust your energy expenditure to match your reduced intake. Studies in animals show that if you restrict energy intake, their cells actually burn less energy, which is one reason that obesity researchers, in their honest moments, acknowledge that restricting calories is ineffective.”
“Public health authorities want us to practice ‘energy balance,’ which is a new way to say that you shouldn’t take in more calories than you expend. So what does energy balance entail?
It's Impossible to count calories
The low-fat diet that people have been eating in hopes of protecting their heart is actually bad for their heart.
“If you consume about 2,700 calories a day, which is typical if you average men and women together, that’s a million calories a year, or ten million calories in a decade. Over the course of a decade, you’re eating roughly ten tons of food. How accurately do you have to match calories-in to calories- out so that you don’t gain more than 20 pounds over the course of a decade? Because if you gain 20 pounds every decade, you’ll go from being lean in your 20s to obese in your 40s, which many of us do. And the answer is: 20 calories a day!. If you take in an extra 20 calories a day and put it into your fat tissue, you will gain 20 pounds every decade.
“The point is, nobody can match calories-in to calories-out with that kind of precision. Twenty calories is like a single bite of a McDonald’s hamburger. It’s a couple of sips of Coca-Cola or a few bites of an apple. No matter how good you are at counting calories, you can’t do it. So if practicing energy balance is really the way to keep from getting fat, the question is, Why aren’t we all fat?”
What we tell people to do to lose weight - eat less and exercise - is exactly what you’d do if you wanted to make yourself hungry.
Exercising won't keep you thin.
“People in nutrition are so keen on making us lose weight by exercising that they’ve forgotten the fact that the more energy you expend, the hungrier you get. Imagine I asked Alice Waters, the great chef from Chez Panisse, to my house to make a 12-course feast, and you’re invited. And I’ve got a pastry chef coming and a gourmet butcher - in Berkeley they have gourmet butchers now. Bring your appetite!
“The two things you’re likely to do are that you might skip lunch, and you might exercise more. You might even say, Look, Taubes lives three miles from my house - I’m going to walk there, and by the time I get there, I’m going to be hungry. The joke is that the two things we tell people to do in order to lose weight - eat less and exercise more - are the exact two things you would naturally do if you wanted to make yourself hungry.
“When you look at the data from research on obesity and exercise, there’s no compelling evidence that exercise has any effect on weight. The American College of Sports Medicine says in its guidelines, which were issued jointly with the American Heart Association, that it’s reasonable to assume that if you exercise more, you’ll be less likely to gain weight over time. But in those same guidelines, it also says that so far, data to support this hypothesis are not particularly compelling. Which is the kiss of death. It’s a 100-year-old hypothesis - if the data aren’t compelling by now, you can be pretty confident that the hypothesis is wrong.”
But there is a way to lose weight
“Our mothers grew up believing refined carbohydrates and starches were fattening - pasta, potatoes, bread, sweets, rice, and corn. And they were right: These foods literally make you fat. Sweets are probably the worst, along with sugar-water combina- tions, which can be anything from fruit juice to Coca-Cola. The reason is that refined carbohydrates raise your insulin levels. Scientists have known since the early 1960s that insulin is the primary hormone that regulates your fat tissue. This is not controversial - if you go to an endocrinology textbook and look up what makes a fat cell fat, it’ll tell you all the ways insulin does it. Then you look up obesity, and it’ll say people get fat because they eat too much and exercise too little. There’s a complete disconnect between the fundamental science and the cause of human obesity.
“All I’m saying to obesity researchers is, Pay attention to the hormonal and enzymatic regulation of the fat tissue. If you do, you’ll get a different answer for what causes obesity and what cures it. Basically, Dr. Atkins got it right with the Atkins diet, although he didn’t get all the science right.”
“We tend to think of our fat cells as a long-term bank account, where your body stores excess calories as fatty acids, which you don’t use until you’re starving. But the reality is that your fat tissue is more like your wallet, and your meals are like going to the ATM. You know how you use the ATM: You put the cash in your wallet and gradually spend it, and when you get too low, you go back to the ATM.
But insulin locks the money in your wallet, so you’ve got to keep going back to the ATM. Your fat cells are getting fatter and fatter, but you can’t get at the fatty acids that are stored inside them. So you get hungry and you eat again.”
“When I was first getting into this subject, I tried the Atkins diet as an experiment. It had never crossed my mind to do that - I associated it with quackery. But now I would go to a restaurant with friends, and they would get skinless chicken breast with green salad, and I would get a pepperoni and melted mozzarella cheese appetizer and a steak. The weight just dropped off. If I walked down the street, it was like you could see the pounds lying behind me on the sidewalk.
“I eat eggs and bacon or sausage for breakfast every day. At lunch, I might have three quarters of a pound of hamburger with cheese, no bun. Dinner is a pound of steak or half a roast chicken or the largest piece of fish I can buy, and vegetables. You eat what you want until you’re satiated - you just don’t eat the things that will make you fat.
“You go on this diet and eat breakfast, and suddenly it’s two o’clock and you’re thinking, Oh, I really should eat lunch. But you’re not hungry. I used to eat a very low-fat diet, and I was hungry every two hours or so. And I gained weight every year.
“The biggest study so far on low- carb diets came out last year. It compared a low-fat diet in which you got
A low carb diet is key
Not everyone gets fat from eating carbs, and getting rid of carbs might not make you lean. But it will make you the leanest you can be.
1,200 to 1,800 calories per day with a low-carbohydrate diet where you could eat as much as you wanted. The researchers kind of buried this part of it, by the way. They barely touched on the fact that this is a severely calorie- restricted diet compared with an all- you-can-eat diet. But what they found was that the low-carb diet did just as well. To me, this has been the most important observation in the field of
obesity research: that you can have an effective diet that doesn’t restrict calories. But the establishment has ignored that aspect of it. And in most of the studies that have been done, a low-carb diet actually does better than a low-fat, low-calorie diet.”
High Fat is better for your heart
“The idea that dietary fat causes heart disease is deeply, deeply ingrained. We all know the Atkins diet kills peo- ple—that’s what we’ve been told, any- way. When I started eating this way, my wife made me get a life insurance policy. But over the past decade, doz- ens of studies have finally looked at the Atkins diet, and they show that heart disease risk factors improve more on this kind of low-carb diet than on the low-fat, low-calorie diet that doctors and the American Heart Association want you to eat. Your HDL goes up, which is the most meaningful number in terms of heart health. Small, dense LDL—which is particularly dangerous—becomes large, fluffy LDL. And not only does your cholesterol profile get better, your insulin goes down, and your in- sulin resistance goes away, and your blood pressure goes down.
“The low-fat diet that people have been eating in hopes of protecting their heart is actually bad for their heart, because it’s high in carbohy- drates. The public health effort to get everyone to eat that way is one of the fundamental reasons that we now have obesity and diabetes epidemics.”
Author and educator Gary Taubes shares timely information with early childhood educators in Santa Cruz County on nutrition and preventing diabetes, starting with the food prepared for young children. The presentation took place at the 2016 Together for Kindergarten community forum. This video is a must view for everyone!
Q&A with Gary Taubes
Q| Can insulin resistant individuals manage weight with the calories in vs. calories out method?
A| In the short run anyone can lose weight by reducing calories significantly, although I’d argue that the fat loss is primarily because of the restriction of carbohydrates that comes naturally with the calorie restriction. The question is, will this work in the long run and would our insulin resistant individual (or non-resistant, for that fact) fare far better on a carbohydrate restricted diet, unrestricted in calories? The clinical trial evidence suggests that the answer to the first question is no, and to the second is yes.
In the short run anyone can lose weight by reducing calories significantly, although I’d argue that the fat loss is primarily because of the restriction of carbohydrates that comes naturally with the calorie restriction. The question is, will this work in the long run and would our insulin resistant individual (or non-resistant, for that fact) fare far better on a carbohydrate restricted diet, unrestricted in calories? The clinical trial evidence suggests that the answer to the first question is no, and to the second is yes.
Q|Scientifically, how does malnutrition/undernutrition work to cause overweight/obesity?
A| It’s not that undernutrition causes obesity, but that it’s possible
to have obesity in populations that are what we’d describe as undernourished, in that they’re not getting enough food to stay healthy. How does this work? I’d argue that the sugar in the diets cause insulin resistance. This takes time to manifest itself, so you see it in the adults not in the children. Once the adults are insulin resistant, they over-secrete insulin in response to all the carbs in the diet. This hyperinsulinemia, as it’s technically known, causes them to partition more of the calories they’re consuming into their fat tissue.
They compensate by expending less energy in metabolic processes and physical activity. Their bodies become more efficient and they’re less motivated to be physically active. As this process continues – more calories partitioned into storage in the fat tissue and a greater compensatory reduction in energy intake — eventually these individuals reach a point where they can remain fat on a diet that doesn’t provide enough calories and nutrients for their growing children. The carbohydrates in these diets literally make these people fat and the amount of calories they consume is almost irrelevant.
Q| Are poor populations overweight because of the types of food they eat or is it a result of severe calorie restriction and fat accumulation as a survival response?
A| Because of the types of food they eat – the effect of the refined grains and sugars in the diet leads to fat accumulation. All species of animals go through periods of severe calorie restriction – winter, for instance – and they’ve all evolved mechanisms to cope with
it – migration and hibernation, for instance. Yet none of them get chronically obese as humans do when food is plenty. So I’m arguing that it’s not the quantity of the food humans eat (or don’t eat) that makes them fat, but the quality – the refined grains and sugars that stimulate insulin levels and cause fat to accumulate.
Q| Why do you think doctors tell obese patients to eat less instead of teaching them how to eat healthily?
A| First of all, if they told them to eat healthily, as it’s currently defined, they’d tell them to eat low-fat, carbohydrate-rich diets – and that’s part of the problem. Secondly, doctors are taught the conventional wisdom in medical school and through the journals they read, and the conventional wisdom is that obesity is an energy balance problem and the way to lose weight is to eat less and exercise more.
Q| If exercising more to lose weight doesn’t work then why do doctors and researchers still use the calories in, calories out model when treating overweight patients?
A| The natural tendency is to assume that the patient didn’t exercise enough. After all, we all know from watching The Biggest Loser that if obese people just exercise enough – say, six hours a day – and, yes, starve themselves while they do it, they lose significant weight. But these interventions are unsustainable in the long run. And they don’t speak to the question of what makes these people fat to begin with.
Q| If overeating and inactivity doesn’t cause fat gain then what does? What regulates fat accumulation?
A| The hormone insulin is the primary regulator of fat accumulation in fat tissue. This is true for most everyone, although other hormones also play a role – estrogen, testosterone, stress hormones, etc. The easiest way to learn about this is to get an endocrinology textbook and go to the section on adipocytes (or fat cells). The book is likely to tell you that obesity is caused by eating too much and inactivity, but it will also discuss (in a different section, of course) the hormones and enzymes that regulate fat accumulation in fat cells and how they do it.
If you want to know how to learn what foods regulate fat accumulation, the easiest way is to remove the foods from your diet beginning with the carbohydrates.
As we are all different, there are
3 important points I would add to this perspective, which is hard to disagree with, but with some caveats.
The low carb or ketogenic diet is extremely effective in weight loss and used therapeutically to overcome chronic conditions, such as cancer, mental & neurological disorders. There are dozens of versions, ranging from Atkins, to Ketogenic, GAPS, SCD, and even Paleo, if taken to the extreme.
1. Carb tolerance
One man's meat is another man's poison. Bio-individuality is key in understanding what works for some people and not others. Gender, age, activity levels, gut biome diversity, culture, environement and genes all play a part.
Therefore once the desired weight or health goal has been reached, some people may need to work out their own 'carb tolerence' i.e. the amount of carbs they need to fit their age, gender, activity rates etc in order to maintain their ideal weight.
Mark Sisson has devised The carbohydrate curve which works well for most:
2. Fat Metabolism
When transitioning from a normal carbohydrate filled diet, if ones digestive health is less than optimal, care needs to be taken to ensure that fat metabolism is optimised. Healthy stomach acid, sufficient enzymes, and good liver function and bile are all needed in this process and if not working well can cause some issues. Digestive aids can be taken during the transition period.
Also, it takes several weeks for the body to ramp up production of fat-burning enzymes on a LC diet as our body switches from carb-burning to a fat-burning metabolism.
3. Gut Flora
Resistant starches and prebiotics are necessary to feed the beneficial flora / microbes in our gut which are an integral part of our daily function and studies show are a major factor in weight gain / loss (see article below). If these start to dwindle we will feel it.
Prebiotic foods such as organic potato starch are often used as well as FODMAPS to keep our internal ecosystem healthy and compensate for a diet too low in these types of foods.
Are the bugs in your gut affecting your fat?
To figure out why people react so differently to the same foods, researchers studied participants’ microbiomes – their unique collection of good and bad bacteria.
This investigation showed that obese people have a less diverse microbiome than thin people, proving that variation in bacteria is key to health and weight maintenance.
In an experiment on mice scientists found that when they transferred bacteria from obese mice to lean mice, the lean mice became obese without a change in food intake!
It’s clear from this experiment that gut flora plays a big role in how our bodies respond to food.
Every food affects individuals differently. There’s no one-size-fits-all approach to diet and nutrition.
There are many factors that affect the risk of obesity and metabolic disorders, and blood sugar regulation and microbiome diversity are key.
How Gut Bacteria Help Make Us Fat and Thin
An early hint that gut microbes might play a role in obesity came from studies comparing intestinal bacteria in obese and lean individuals. In studies of twins who were both lean or both obese, researchers found that the gut community in lean people was like a rain forest brimming with many species but that the community in obese people was less diverse - more like a nutrient-overloaded pond where relatively few species dominate. Lean individuals, for example, tended to have a wider variety of Bacteroidetes, a large tribe of microbes that specialize in breaking down bulky plant starches and fibers into shorter molecules that the body can use as a source of energy.
Documenting such differences does not mean the discrepancies are responsible for obesity, however. To demonstrate cause and effect, Gordon and his colleagues conducted an elegant series of experiments with so-called humanized mice, published last September in Science. First, they raised genetically identical baby rodents in a germ-free environment so that their bodies would be free of any bacteria. Then they populated their guts with intestinal microbes collected from obese women and their lean twin sisters (three pairs of fraternal female twins and one set of identical twins were used in the studies). The mice ate the same diet in equal amounts, yet the animals that received bacteria from an obese twin grew heavier and had more body fat than mice with microbes from a thin twin. As expected, the fat mice also had a less diverse community of microbes in the gut