Why Exercise Does Not Make You Thin

Despite my own modest exercise, (two days a week of pushups, pullups, dips and burpees and two days of running — one day long distance and the other 10×100 meter sprints) I have written previously that exercise will not work for weight loss. I routinely advise people on my forum to cut back or eliminate their weight training to lose weight and invariably it works. It may surprise you to know that prior to the 1960s, that is precisely what doctors told their patients. They told them not to exercise. William Banting of England told us all back in the 1800s that when he began to increase physical exertion by becoming a logger, it only made him ravenous.

The problem is that this theory of physical activity has long been contradicted by the evidence. In 1932, Russell Wilder noted that his patients tended to lose more weight with bed rest than they did with strenuous physical activity. He said, “The patient reasons quite correctly that the more exercise he takes the more fat should be burned and that the loss should be in proportion and he is discouraged to find that the scales reveal no progress.”

In the 1960s, the “experts” continued to point out that moderate exercise would only lead to insignificant increases in energy expenditure and these could easily be matched by slight and comparatively effortless changes in diet.

As the old saying goes, “Those who do not know their history are destined to repeat it.”

In today’s big article in Time Magazine, the author points out:I have exercised like this – obsessively, a bit grimly – for years, but recently I began to wonder: Why am I doing this? Except for a two-year period at the end of an unhappy relationship – a period when I self-medicated with lots of Italian desserts – I have never been overweight. One of the most widely accepted, commonly repeated assumptions in our culture is that if you exercise, you will lose weight. But I exercise all the time, and since I ended that relationship and cut most of those desserts, my weight has returned to the same 163 lb. it has been most of my adult life. I still have gut fat that hangs over my belt when I sit. Why isn’t all the exercise wiping it out?

It’s a question many of us could ask. More than 45 million Americans now belong to a health club, up from 23 million in 1993. We spend some $19 billion a year on gym memberships. Of course, some people join and never go. Still, as one major study – the Minnesota Heart Survey – found, more of us at least say we exercise regularly. The survey ran from 1980, when only 47% of respondents said they engaged in regular exercise, to 2000, when the figure had grown to 57%.

And yet obesity figures have risen dramatically in the same period: a third of Americans are obese, and another third count as overweight by the Federal Government’s definition. Yes, it’s entirely possible that those of us who regularly go to the gym would weigh even more if we exercised less. But like many other people, I get hungry after I exercise, so I often eat more on the days I work out than on the days I don’t. Could exercise actually be keeping me from losing weight?

We’ve known since at least 1940 that a significant increase in energy expenditure also leads to an increase in appetite. Northwestern University endocrinologist Hugo Rony stated in 1940 that “vigorous muscle exercise usually results in immediate demand for a large meal.” Statistics support the fact that lumberjacks eat more than 5,000 calories while sailors eat only about 2,500. Most of us have seen the training tables of professional football players and boxers who eat tremendous amounts of food.

There is every reason to believe that if a sailor became a lumberjack, he would soon develop the appetite of his fellow lumberjacks.

By at least 1960, it had been amply demonstrated that exercise is an ineffective method of increasing energy output and that physical exertion eventually evokes a desire for food such that the subsequent intake of calories may exceed that lost during exercise.

So what changed from 1960 until today where exercise is back in vogue and considered “indispensable” as a weight loss method?

The conventional wisdom that exercise is essential for shedding pounds is actually fairly new. As recently as the 1960s, doctors routinely advised against rigorous exercise, particularly for older adults who could injure themselves. Today doctors encourage even their oldest patients to exercise, which is sound advice for many reasons: People who regularly exercise are at significantly lower risk for all manner of diseases – those of the heart in particular. They less often develop cancer, diabetes and many other illnesses. But the past few years of obesity research show that the role of exercise in weight loss has been wildly overstated.

However, this could just as easily be called an association and not a cause. Perhaps healthy people tend to exercise more than non-healthy people. Perhaps people exercise BECAUSE they are healthy. That seems to fit better than the alternative. Exercising seems to do very little to get one healthy who is not already fairly healthy to begin with.

“In general, for weight loss, exercise is pretty useless,” says Eric Ravussin, chair in diabetes and metabolism at Louisiana State University and a prominent exercise researcher. Many recent studies have found that exercise isn’t as important in helping people lose weight as you hear so regularly in gym advertisements or on shows like The Biggest Loser – or, for that matter, from magazines like [Time].

The basic problem is that while it’s true that exercise burns calories and that you must burn calories to lose weight, exercise has another effect: it can stimulate hunger. That causes us to eat more, which in turn can negate the weight-loss benefits we just accrued. Exercise, in other words, isn’t necessarily helping us lose weight. It may even be making it harder.

Earlier this year, the peer-reviewed journal PLoS ONE – PLoS is the nonprofit Public Library of Science – published a remarkable study supervised by a colleague of Ravussin’s, Dr. Timothy Church, who holds the rather grand title of chair in health wisdom at LSU. Church’s team randomly assigned into four groups 464 overweight women who didn’t regularly exercise. Women in three of the groups were asked to work out with a personal trainer for 72 min., 136 min., and 194 min. per week, respectively, for six months. Women in the fourth cluster, the control group, were told to maintain their usual physical-activity routines. All the women were asked not to change their dietary habits and to fill out monthly medical-symptom questionnaires.

The findings were surprising. On average, the women in all the groups, even the control group, lost weight, but the women who exercised – sweating it out with a trainer several days a week for six months – did not lose significantly more weight than the control subjects did. (The control-group women may have lost weight because they were filling out those regular health forms, which may have prompted them to consume fewer doughnuts.) Some of the women in each of the four groups actually gained weight, some more than 10 lb. each.
What’s going on here? Church calls it compensation, but you and I might know it as the lip-licking anticipation of perfectly salted, golden-brown French fries after a hard trip to the gym. Whether because exercise made them hungry or because they wanted to reward themselves (or both), most of the women who exercised ate more than they did before they started the experiment. Or they compensated in another way, by moving around a lot less than usual after they got home.

I’ve written about the “Gatekeeper Hypothesis” before. M.R.C. Greenwood, a student of Jules Hirsch at Vassar College presented the “gatekeeper hypothesis” of obesity in 1981, Gary Taubes reported that researchers found that obese humans have increased LPL activity in their fat tissue. Moreover, they have found that LPL activity in fat tissue increases with weight loss on a semi-starvation diet and it decreases in muscle tissue. This will negate any negative energy balance that may be induced by semi-starvation.

During exercise, LPL activity increases in muscle tissue to enhance the flow of fatty acids (the body’s preferred fuel) to the muscles for fuel. But when the workout is over, LPL activity in the fat tissue increases which serves to restock the fat tissue with whatever fat may have been lost to exercise. This led University of Colorado physiologist Robert Eckel to opine that “habitual carbohydrate intake may have a stronger effect on subcutaneous fat storage than does dietary fat intake.”

So these exercisers who “compensate” for the fatty acids lost during exercise are only doing what they should be doing. This should inform us that something is very wrong with the theory.

Then how did the exercise-to-lose-weight mantra become so ingrained? Public-health officials have been reluctant to downplay exercise because those who are more physically active are, overall, healthier. Plus, it’s hard even for experts to renounce the notion that exercise is essential for weight loss. For years, psychologist Kelly Brownell ran a lab at Yale that treated obese patients with the standard, drilled-into-your-head combination of more exercise and less food.

“What we found was that the treatment of obesity was very frustrating,” he says. Only about 5% of participants could keep the weight off, and although those 5% were more likely to exercise than those who got fat again, Brownell says if he were running the program today, “I would probably reorient toward food and away from exercise.”

In 2005, Brownell co-founded Yale’s Rudd Center for Food Policy and Obesity, which focuses on food marketing and public policy – not on encouraging more exercise.
Some research has found that the obese already “exercise” more than most of the rest of us. In May, Dr. Arn Eliasson of the Walter Reed Army Medical Center reported the results of a small study that found that overweight people actually expend significantly more calories every day than people of normal weight – 3,064 vs. 2,080. He isn’t the first researcher to reach this conclusion. As science writer Gary Taubes noted in his 2007 book Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health, “The obese tend to expend more energy than lean people of comparable height, sex, and bone structure, which means their metabolism is typically burning off more calories rather than less.”

In short, it’s what you eat, not how hard you try to work it off, that matters more in losing weight. You should exercise to improve your health, but be warned: fiery spurts of vigorous exercise could lead to weight gain. I love how exercise makes me feel, but tomorrow I might skip the VersaClimber – and skip the blueberry bar that is my usual postexercise reward.

Now that’s some of the best dietary advice I’ve seen in a long time. The bottom line is that carbohydrates cause weight gain. Good carbs cause cravings for more refined carbohydrates. They are like a gateway drug to bingeing on sweets. Get rid of all carbohydrates and you will control both hunger and cravings. Any diet that does not control hunger and cravings is an improper diet. Exercise if you want to and because you enjoy it. Don’t rely on it to look like me.

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