90% Of Sustained Weight Loss Includes Exercise and Diet

The aim: To dismantle the confusion about exercise and diet as they relate to weight loss.  I present several studies that may seem contradictory and try to find the nuggets of truth.

IF YOU’RE the average bear, I spend a lot more time reading and experimenting with exercise and diet than do you.  Not bragging, nor implying some superior value, but setting up the next statement.

The data can be confusing, and sometimes it confuses me, despite my focus on this subject matter.

To wit, a New York Times Magazine article I clipped out about a year ago and put in a pile for this blog’s potential post material.  I flipped through the pile today, and selected this article for dissemination and dissection: Weighing the Evidence on Exercise, by Gretchen Reynolds.

As you would expect from an article gracing the pages of the New York Times Magazine, this one is well written and informative.  But did I mention confusing?

Up front, I wish to exonerate dear Ms. Reynolds from in artful confusing collaboration; rather, my focus is on the data, the studies about exercise and diet and what works and what doesn’t relative to the prevalent obsession with weight control.

Simply speaking, the data are confusing, as “Weighing the Evidence” makes evident.

Note the following assertions, all asserted to be true, or mostly so:

  1. Exercise can help you lose weight, but only sometimes and most often if you’re a man.
  2. Exercise can make you eat more, but not always… just depends.
  3. Eating more due to exercise can negate it’s weight losing effect except when it doesn’t.

Get it?  Clear as mud.  Well, the rest of this post is devoted to fleshing out the particulars presented in Weighing the Evidence on Exercise (which I suggest you read) which can actually make all those assertions written above true.  Kinda.

Let’s begin with Eric Ravussin, a professor at the Pennington Biomedical Research Center in Baton Rouge, La., and an expert on weight loss, who says:

“In general, exercise by itself is pretty useless for weight loss.”

This statement occurs in the third paragraph and is the start of a series of head scratching exercises on my part, for it contravenes everything I’ve personally experienced and thought I knew about exercise.

Why does Professor Ravussin say that?  He says it’s because the body aims for homeostasis and that means here that it will endeavor to maintain the weight to which it’s accustomed.

But, there’s evidence to that suggests that gender has something to do with it. The American Journal of Physiology conducted a study whereby men and women walked on treadmills.  This activity did not produce increased appetites for the men, but did for the women.

Unfair, but perhaps true – a woman’s body wants to maintain energy stores (aka “fat”) for reproduction.

The net of these two studies: “Exercise for many women (and for some men) increases the desire to eat.”

All, however, is not lost.  There’s more research to with which to flagellate ourselves.

Researchers from Harvard University looked at the weight-change histories of more than 34,000 participants in a women’s health study. The women began the study middle-aged, averaging 54 years old, and were followed for 13 years.


Those women who reported doing non-strenuous exercise almost every day for about an hour stayed closest to their starting weight.  The non-exercisers gained, some considerably.

That this exercise was “non-strenuous”, such as walking, suggest that this is all you need if you’re consistent and the aim is to maintain weight, or lose a bit of weight.

Given that about 2/3rds of Americans are OVERWEIGHT, however, a stroll in the park may be deemed insufficient.

Yep, it’s true.  There’s something called the National Weight Control Registry.  Barry Braun, an associate professor of kinesiology at the University of Massachusetts at Amherst, says that about 90% of the people in the “registry” who have shed pounds, did so through exercise and, importantly, kept off the pounds over time via exercise.

In one experiment, 97 slightly overweight women were put on an 800-calorie per day diet until they each lost an average of 27 pounds.  After that they were divided into three groups: the walkers, weight lifters and non-exercisers.  All returned to their prior eating habits.

Results: “Those who stuck with either of the exercise programs regained less weight than those who didn’t exercise and, even more striking, did not regain weight around their middles. The women who didn’t exercise regained their weight and preferentially packed on these new pounds around their abdomens”, which contributes significantly to metabolic disruptions and heart disease.

The next study contemplated was with rats.  You can do things with rats that you can’t with people, and much of the biology is the same.

Scientists at the University of Colorado at Denver conducted an experiment to test if exercise reset metabolism such that exercising rats would eat less, or stay less fat than the non-exercising group, even once they no longer exercised.

This is what the rat researchers did… 1. Rats were overfed and got fat; 2. All were put on a diet and lost 14% of their weight; 3. They were then put on a weight-maintenance diet, but half were exercised 30 minutes/day most days, and the other half remained sedentary; 4. After a new base-line weight was established, all rats were allowed to eat as much as they wanted.

Results: (This shows the power of exercise.) The non-exercising rats ate with abandon and regained the weight and more.  In stark contrast, the exercising rats burned fat after their meals (the other burned carbs which became fat cells) AND they ate less!

Although the exercisers regained some weight, their relapses were not as extreme. Exercise “re-established the homeostatic steady state between intake and expenditure to defend a lower body weight,” the researchers concluded. Running had remade the rats’ bodies so that they ate less.

The last study has yet to be published but it’s worth presenting.

Professor Braun and his colleagues wanted to test just how much movement is necessary to affect calorie burn.  One group sat all day, the other mostly stood.  The difference in energy expenditure was remarkable, representing “hundreds of calories,” Braun says. Standing, for both men and women, burned multiple calories but did not increase hunger.  Braun concludes: if you want to lose weight, you don’t necessarily have to go for a long run. “Just get rid of your chair.”

My Conclusions

Let’s go back to the “three assertions” stated above, where are:

  1. Exercise can help you lose weight, but only sometimes and most often if you’re a man.
  2. Exercise can make you eat more, but not always… just depends.
  3. Eating more due to exercise can negate it’s weight losing effect except when it doesn’t.

Each of these were suggested by one or more of the studies cited, and they may be mutually exclusive or contradictory in the abstract; meaning under specific research conditions.  Taken together, though, and applied to real life, this is what I think:

A. Unless you employ a rigorous exercise program, if you want to lose fat, you need to consume less and better calories.  (Better = veggies, fruits, lean meats.)

B. On average, men can do “A.” better than women, perhaps because they have more testosterone which builds muscle easier and muscle burns more calories.  But then women get to have babies.

C. Yes, if rigorous enough, you’ll want to eat more to feed those new growing muscles, but if you eat right and only feed the muscle – not add to the fat reserves – you won’t negate the fat loss, even if you gained weight, muscle weight.

Any thoughts on the matter?  Please weigh in at the Comments section below.

Last Updated on November 8, 2022 by Joe Garma

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Joe Garma

I help people live with more vitality and strength. I'm a big believer in sustainability, and am a bit nutty about optimizing my diet, supplements, hormones and exercise. To get exclusive Updates, tips and be on your way to a stronger, more youthful body, join my weekly Newsletter. You can also find me on LinkedIn, Twitter and Instagram.

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