Video: Gary Taubes Interview: Low Carb Diet and Exercise
So Gary, thank you very much for the interview. And, in a nutshell, what makes us fat? In a nutshell, the argument I'm making is pretty simple. It's 'obesity is a growth disorder', just like any other growth defect. The hormone involved is insulin, and if insulin is involved, you have to assume it's the carbohydrate content of the diet. And… for… 50 to 150 years, depending on how you what to look at it, or almost 20 years now, there has been this conventional wisdom that carbohydrates are fattening. And there's evidence that if you take the carbs out of the diet, and replace them with fat, you can lose weight pretty easily, and without hunger and without the kind of deprivation you feel on other diets.
So I would say carbohydrates make us fat. OK. I've talked to some people that are sort of in the 'diet realm', but haven't investigated it fully. And the first thing they say when I say, "Well, what do you consider about a low carbohydrate diet?" And the first thing they say is, "Well, then your body goes into ketosis and that's so, so horrible. You can't possibly live like that!" They're confusing 'ketosis' with 'ketoacidosis', which is a condition you get in diabetes where ketone levels skyrocket. It's like, you know, ketosis is a pretty normal state. I mean, in the morning when you wake up your body is secreting, your liver is pumping out some ketones. Not as much, so… You know, it's a kind of knee jerk response that this has to be bad because if your'e an uncontrolled diabetic your ketone levels will be ten times as high. And… It's a primitive, kind of, response to why this diet must be bad for you. And you know, again, I'm not arguing that you have to be in ketosis.
I'm saying that carbohydrates are fattening – don't eat them. One way to deal with that is to do a diet where, again, you increase fat consumption sufficiently so that you are in ketosis. And if you are overweight, really obese, it's probably a good idea to do that. But it's not necessary. Yea, the point of the book is not that everybody should be in a ketotic state. The point of the book is that we shouldn't eat refined grains and sugars, and we'll be a lot healthier. So that's what I'm arguing. So, if you were put in charge of, like, public health policy – you woke up the next morning and you were in charge of U.S. dietary health, what would you do? What's, like, the first thing you would do? If I was king of the universe, what would I do? Just for the food. I would probably somehow remove sugar from the food supply.
Sugar and high-fructose corn syrup. And I would do this in part for my children, and all children everywhere. I just… As a parent, it offends me at how difficult it is to buy a food that doesn't have sugar in it. And doesn't have far more sugar in it than necessary to make it sweet. And so, yea, if I didn't get rid of sugar entirely I would lower the sugar content of foods by, like, a factor of five. Which is probably sufficient. And again, that's speaking as much as a parent of two young sons as it is a person who has done research on nutrition for the past ten years. OK, well, you've made the argument in your talks that, as far as just the caloric burn from exercise, that's completely… you're not going to lose weight because of that, and nobody can sustain exercise. But exercise does give you a lot of other benefits.
.. I'm not… I'm a big believer in exercise. I've been a jock my whole life, I've tried to work out as much as I can. The argument that I'm making is it's not… You don't lose weight by increasing energy expenditure. The clinical trials are pretty clear about that. You can do it temporarily, like on The Biggest Loser, yea workout 6 hours a day – you'll lose weight. Just like you can starve yourself and you'll lose weight. But it's not a sustainable (not that exercise isn't sustainable), six hours of exercise a day in order to maintain that weight loss isn't sustainable. And you can't even be guaranteed that the weight won't come back even though you're doing it six hours a day. So that's the point. The argument is that obesity, weight, this excess fat isn't about energy balance. It's about the way your body is trying to regulate your fat tissue and fat metabolism. And that's what's gotta be fixed. And you don't fix that by increasing exercise, you fix that by removing the carbohydrates from the diet that are driving this insulin secretion. Insulin's anabolic effect is not just limited to fat tissue. It does a lot of other.
.. Yea, but you'll get that anabolic effect from the protein in the diet as well. In fact, one argument… What's interesting is if you do want to eat a ketogenic diet and you workout a lot, the knee-jerk tendency is to assume 'because I workout a lot I need a lot of protein in the diet', and then the protein brakes down into amino acids, some of which are converted to glucose which stimulate insulin secretion. So if you actually want a ketogenic diet you have to lower your protein intake as well. And that's why it becomes a high fat diet, rather than a high protein and high fat diet. But when it actually gets into the minutia of exercise physiology, that's not my area of expertise. I was just curious about how that [insulin] had other effects. Especially, because as far as the health implications of the diet more than just losing 20 or 40 pounds… Or 200 or 300 or more! Or a hundred or 200 or more, as is the case for some people. A lot of the other effects, which are blamed on fat, like heart disease, diabetes, and cancer, especially.
I'm just more aware of cancer because people in my family have had cancer. Well, that's what – the argument that we're looking at here is that all these disorders are associated with obesity and diabetes. So if you're obese or diabetic, type II diabetic, then you have in increased risk of heart disease and of cancer and of alzheimers, apparently, and so they all have very strong links to insulin, and insulin resistance. And the argument is, again, that by keeping your insulin levels as low as possible you minimize your risk of these cancers. And this could conceivably explain, again, why isolated populations that ate their traditional diets didn't get cancer, not nearly at anything like the rates we do today, and it's because they weren't eating refined grains and sugars and jacking up their insulin levels and (sort of) promoting tumor growth, or tumor genesis. So I can make an argument that the ideal cancer prevention diet is a very low carbohydrate, high fat diet. Is there clinical trial evidence to support that? No.
That's a difficult study to do. That takes a lot of money, because… when you're talking about things like cancer, it takes a long time to get cancer so you need a lot of people in the study and you have to follow them for a long time, and now you're talking hundreds of millions of dollars… Lots of variables. Yea, and it's difficult to do the studies right. Again, it's arguable that that's the healthiest diet. And I've met cancer researchers who have told me that they're on, in effect, an Atkins like diet. It's not because they have to lose weight, but because they don't want to get cancer. So being on that sort of ketogenic diet… what level of carbs do you think is healthy? You were saying earlier that fruit, you're not so hot on some kinds of fruit.
But… Yea. And again, this is where it gets into questions that… it depends. One of the ideas that's sort of inherent in this whole low carb/paleo diet world is it goes along with self experimentation. So you find out what level works for you, that keeps you lean and keeps you healthy and your heart disease risk factors under control. But you're content within, perhaps, depending on the kind of exercise you do, you might decide to up carb intake. I don't know if it's actually necessary, but people believe it is. So, you know, again, if you're a hundred pounds overweight then you're looking at a different situation than if you're 15 pounds overweight, or if you are completely happy with your weight but you want to live the healthiest possible lifestyle. So, again, those numbers are going to differ for everyone.
One of the things that I'm always curious about is, "Do you have to actually be in ketosis?" Do you have to eat less than, like, 50 grams of carbs a day and 100 grams of protein, or, for some people, is that necessary to lose weight? If so, what proportion of the population is that? We don't know the answers to that. Although those are easier studies to do than the, well, how do you prevent cancer studies. I see. Do you know how insulin itself effects irisin and leptin, 'cause the more I've personally been looking at this there seems to be this conglomeration of hormonal actions that influence each other. Obviously we can directly control insulin to a degree we can't with others. Well, it's actually conceivable that we can directly control leptin, that leptin responds to carbohydrate restriction quicker than insulin does. That's an argument that Ron Rosedale has been making, and he may be the only one out there who's measuring leptin, at least on ketogenic diets, and seeing how it responds.
It is this kind of, I don't know if the word 'conglomeration' captures the sort of intricate, complex dance of hormones. Like ecosystem? Or… Yea, I think of it as this almost incomprehensibly complex web and you pull a little bit here, and it moves a little bit there, and… Yea insulin, or insulin and leptin, are things we can control through our diet. So, you know, at some level leptin is secreted in response to insulin, and the blood sugar being moved into, as I understand it, being moved into fat cells by elevated levels of insulin. How that feeds back on insulin secretion, and it does, and on insulin sensitivity, is something I would like to try to understand, but I'm not sure the papers are clear enough. At the moment I don't have the time, it's that simple. Yes. So, is there any evidence, because I know that is some mouse trials they have used ketogenic diets to extend life, the lifespan.
.. Well the argument is… How does calorie restriction extend lifespan? Most researchers believe it does this, in effect, by surpassing the insulin like growth factor signaling pathways, and some of the other signaling pathways that feed into that, like mTOR. So that when you calorie restrict animals it's the equivalent, in effect, to carbohydrate restricting humans. With animals, putting them on ketogenic diets gets a little more tricky because they would have consumed mostly low fat diets through their evolutionary history, and now you're loading them up with fat you get other phenomena that occur from that. What I'm suggesting in my books is that the benefits of calories restriction in animals would be mimicked in man by carbohydrate restriction, just suppressing insulin and IGF as far down as it would go.
But if we are going to de-accelerate aging by doing that, then I'd better start seeing effects soon. Or getting more sleep, one or the other. One last question. Based on your personal experience, and what you've read, if somebody wanted to start a ketogenic or a low carb diet, do you think they should taper down, or just completely switch, or… That's an interesting question, and again it depends on the individual. I do tend to think of this in terms of cigarette smoking, because I used to be a smoker. On one level you could argue that I tapered down for a decade before I successfully quit. And in fact I went from smoking cigarettes to little cuban cigars that I would only smoke four a day, even though it had the nicotine of, like, three packs of Marlboro's. Ultimately, you end up going cold turkey.
So I'm just not sure really, which – it might depend on the psychology of the individual, it might depend on the physiology of the individual. It could just be that the easiest thing to do would be to give it all up. In this day and age you would never tell an alcoholic to 'taper down', I mean alcoholics try to do that all the time. It's usually, "I'm trying to quit. I'm only drinking wine these days", and it invariably fails. As a former smoker I tapered down, like I said, for decades before I finally quit. But eventually you just have to go cold turkey. Again, I could argue it either way. I have a friend, a colleague, that thinks tapering down is the way to do it because that's how he did it. But I could argue that cold turkey may be correct for everyone else. Had he tried cold turkey, it might have worked equally well. This is the kind of thing – if we ever win this battle, we get the medical research establishment to accept that it's carbs that are the problem, all those psychologists who are right now trying to get obese people to eat less and exercise more could actually be put to use trying to do studies to figure out what are the best ways to restrict carbohydrates, and to ameliorate the psychological side effects of doing this.
The dependency. The dependency, yea. All those people who study addiction, instead of thinking about it as food addiction, could think about it as carb addition, or sugar addiction. And actually do something useful. All right. Gary, thank you so much for your time. Thank you, Aaron..