- How important is exercise to being healthy?
- How important is exercise to losing weight?
- Do we need carbohydrates for energy?
- If exercise isn’t important to losing weight, why then are all the contestants on The Biggest Loser losing so much weight?
- Does eating fat make us fat? Is eating fat unhealthy?
- How important is counting calories to losing weight or maintaining a healthy weight?
- Why do most health “experts” today advocate a low fat diet?
- What is insulin resistance?
- Are obese people overweight because they are too lazy to exercise and eat too much?
- How does cancer figure into what we eat?
- Why are the obese likely to get diabetes?
- What role does sugar play on obesity and on overall health?
- Can you build muscle by eating fat?
How important is exercise to losing weight?
It seems intuitively obvious that it should be important, but experimental trials of diet vs. diet plus exercise invariably show that the exercise makes effectively no difference on weight loss.
The world is full of overweight and obese people who work at physically demanding jobs — hard-working laborers, for instance, who exercise regularly and are even devoted to it and remain just as obese or overweight as ever. I know, personally, many folks (including myself) who have gained significant weight, despite hours of rigorous daily exercise.
This isn’t controversial, by the way. It’s this research that led the American College of Sports Medicine and the American Heart Association in their last physical activity guidelines (2007) to make this statement: “It is reasonable to assume that persons with relatively high daily energy expenditures would be less likely to gain weight over time, compared with those who have low energy expenditures. So far, data to support this hypothesis are not particularly compelling.” (And one of the co-authors of this ACSM/AHA report is an exercise physiologist who described himself as “short, fat and bald” when he started running 30 years ago, and since then has run 85,000 miles, or the equivalent of more than three times around the globe at the Equator, while only becoming “short, fatter and balder,” in his own words.)
How important is exercise to being healthy?
No one doubts that healthy people tend to be physically active people. The question is whether or not you can take unhealthy people and make them healthy merely by exercising them and without any meaningful change in diet. The answer is probably not.
Exercise is important for a number of reasons, but weight management and controlling disease risk are not on the list, at least according to the best available evidence.
Exercise “matters” for at least 5 reasons in our humble opinion: endorphin production (you “feel” better), social interactions, improving competitive skills, increasing endurance and strength, and (perhaps) injury prevention as we age. (Although exercise, of course, also causes injuries if not done correctly.)
Do we need carbohydrates for energy?
This is actually the wrong question. If the question is, “Do we need to eat carbohydrates for energy?” the answer is, no. The conventional wisdom is that we need a minimum of 120 to 130 grams of carbohydrates (glucose) per day to fuel our brains, and we need copious glycogen (the storage form of carbohydrates) for endurance activities. This is just a misconception of what is not controversial science. Our body can fuel both our brains and hours and hours of endurance activities from protein and the breakdown products of fats.
If exercise isn’t important to losing weight, why are all the contestants on The Biggest Loser losing so much weight?
They’re forcing themselves to endure a condition – extreme starvation caused by both diet and exercise–that is physiologically impossible to endure for more than a short period of time. Anyone can lose weight by starving themselves (even thin people, obviously); the problem with this is, how do you stop the weight from coming back when the starvation can no longer be endured?
Their extreme starvation is also carbohydrate starvation, so they are consuming far less carbohydrates than previously and the draconian exercise routine is increasing the effect of this carb-restriction.
The relevant questions are (1) How sustainable is this weight loss? (The answer is, it’s just not.), (2) How does it impact overall health (e.g., disease prevention)?, (3) Most important, is it possible that these contestants would have lost just as much weight by going on a very carb-restricted diet but without the starvation and exercise? Stay tuned on this one.
Does eating fat make us fat? Is eating fat unhealthy?
Again, it seems obvious and this has been the conventional wisdom for fifty years. But experiments over the last decade have demonstrated that people who eat as much as they want of fatty-foods, even foods rich in saturated fat like butter and lard and eggs, lose weight and improve their heart disease risk factors. And this happens even when the comparison group is people eating American Heart Association calorie-restricted, low fat diets.
How important is counting calories to losing weight or maintaining a healthy weight?
In the short-term, anyone can create a huge calorie deficit (i.e., starve themselves) and lose weight. That’s obvious. One fundamental assumption of virtually every successful diet book is that there is some magical mix of nutrients in a diet that allow you to eat more, or even as much as ever, and still lose weight. The conventional wisdom is this is quackery.
The question is (or should be), “How important is calorie counting for long-term, sustainable, weight loss?” The answer to this question is: not important at all. In fact, it’s easy to demonstrate (using 8th grade mathematics) that in order to gain 40 pounds in 20 years – to go from lean in your 20’s to obese in your 40’s, as many people do – all you have to do is stick 18 extra calories a day in your fat tissue that you don’t burn. That’s the equivalent of a single bite of food too many over the course of a day and you’ll become obese.
In fact, long-term weight management is not driven by calorie counting, but rather by changing the way our body treats the food we eat (i.e., burning fat versus storing fat). As you’ll hear me say often, obesity is a disorder of inappropriately accumulating fat, not a disorder of eating too many calories.
Why do most health “experts” today advocate a low fat diet?
It’s one of the great tragedies of the modern era and it speaks to the pitfalls of policy makers having little understanding of science. I don’t know the stats today, but in early 2010, before the last midterm election cycle, only 6 or 7 members of Congress (100 Senators and 435 members of the House) had a background in science. Whether this is any better today I don’t know, but the fact remains, policy makers are not trained to slog through the morass of information and misinformation out there on this topic. That said, we are slowly witnessing a change, at least among certain authorities. Leading health authorities no longer advocate a low-fat diet (as was evidenced by a recent editorial in the New England Journal of Medicine by Walter Willett and David Ludwig of Harvard challenging the science base of the U.S.D.A. Dietary Guidelines). What’s still conventional wisdom, however, is the idea that we should moderate our saturated fat intake. In the past year alone, three recent reviews by unbiased researchers have concluded that the evidence against saturated fats is simply not sufficient to support a recommendation that we eat less of them.
As John Tierney of the New York Times has explained, most health “experts” today advocate a low fat diet or a low saturated fat diet because that’s the conventional wisdom — what everyone else advises — and they never bothered to look into the evidence themselves to see (1) How we came to believe that this might be beneficial, and (2) What the evidence really shows.
What is insulin resistance?
Effectively, insulin resistance (IR) is a progressive condition whereby the body’s cells become more and more resistant to the hormone insulin. As a result, the pancreas has to secrete more and more insulin just to keep blood sugar within a normal range. Insulin resistance is now considered the condition that leads to type 2 diabetes (the kind we get as we get older and fatter), as well as obesity, heart disease and now cancer and perhaps Alzheimer’s disease as well.
Are obese people overweight because they are too lazy to exercise and eat too much?
No, though we are certainly taught this in every aspect of our lives (from so-called “conventional wisdom” to medical education).
People are obese because their fat tissue is wired hormonally to accumulate too much fat. This is not the same as “overeating” or “under moving.”
Overweight people eat too much relative to how much they move (i.e., expend calories) because of constantly elevated insulin levels.
The cause and effect is no different than explaining why pregnant women gain weight or why children grow.
How does cancer figure into what we eat?
The conventional wisdom of the past half dozen years is that the cancer process is driven by elevated levels of two hormones in particular – insulin and insulin-like growth factor. This is evidenced by a whole host of studies showing an increased risk of cancer in obese and diabetic patients and patients who are only insulin resistant but not yet obese and/or diabetic. Furthermore, most major drug companies have drugs in various stages of their pipelines targeting insulin-like growth factor as a treatment for cancer.
Because our insulin levels rise with insulin resistance, as we’ve discussed, the question then becomes what causes insulin resistance. The conventional wisdom there, once again, is that insulin resistance is caused by eating too much (especially too much fat) and sedentary behavior. The unconventional wisdom is that insulin resistance is caused by the nutrient composition of our diet – in other words, the amount of carbohydrates, the kinds of carbohydrates and maybe the fat content as well.
Why are the obese likely to get diabetes?
Both obesity and type-2 diabetes are disorders of insulin resistance. And as we get resistant to insulin we have to pump out more insulin from our pancreas to manage our blood sugar levels. Eventually, the pancreas can’t keep up with the demand and the result is excessively high blood sugar and the diagnosis of type-2 diabetes. So the obese are likely to get diabetes because they’re like to be insulin resistant.
What role does sugar play on obesity and on overall health?
The conventional wisdom is that sugar is no more harmful, calorie per calorie, than any other nutrient in the diet. And yet virtually every diet, even low-fat diets, restrict sugar consumption considerably. (And by sugar, I mean both the white powdered stuff, sucrose, that we put in our coffee and tea, and the ubiquitous high fructose corn syrup in all juices and processed foods.)
Fifty years of biochemistry, though, suggests that sugar is the ultimate cause of insulin resistance (because of the metabolic load it puts on the liver) and so perhaps the ultimate cause of obesity, diabetes and the diseases that associate with them, including cancer and Alzheimer’s disease.
Can you build muscle by eating fat?
Provided you consume a normal amount of protein, yes, you can build muscle by eating fat. Even the Inuit (who consumed more than 90% of their calories from fat) still consumed enough protein to maintain muscle mass necessary for a physically demanding lifestyle.