Does Exercise Help Weight Loss?

I keep reading all these articles that seem to take the position – explicitly or implicitly – that exercise is useless for weight loss.  And, finally I was incredibly annoyed by an article in the Washington Post, Take off that Fitbit. Exercise alone won’t make you lose weight.  When I first saw the first part of this, I thought this was going to be an article railing against activity monitors.  However, this is just another article about how useless exercise is to weight loss.

I recognize that authors don’t always get to write their own headline, so I won’t blame the cardiologist author, Aseem Malhotra, for the headline.  That said, regardless of weight loss, there is no reason to take off your Fitbit.  And, furthermore, it simply goes too far to say that exercise alone won’t make you lose weight.  If exercise results in you having a calorie deficit that you didn’t have before, then you will lose weight.  If you have a calorie deficit due to reduced food intake, and you add on exercise and keep the same food intake, then you will lose even more weight.

It should be obvious, of course, that if you exercise and eat extra food with calories equal to the amount of the exercise, then you won’t lose any extra amount due to the exercise.  If you exercise and eat food with calories greater than the calories burned in exercise, then you will gain weight.  This is not rocket science.  It shouldn’t take more than a moment’s thought to realize these basic facts.

The entire article seems to basically take the position that it is all but impossible for people to exercise and not eat back all their exercise calories.  This seems defeatist to me, and can lead to people being discouraged from exercising.  The author bluntly states:

Exercise — no matter how many gym memberships you buy or how often you wear your Fitbit — won’t make you lose weight.

The fact is that it will make you lose weight, or will increase the amount of weight you are losing, if it results in you having a greater calorie deficit. The author does acknowledge the health benefits of exercise, but goes on to say that “weight loss is not one of them.”

To support this, he in part relies on the fact physical activity increased between 2001 and 2009, but that the increase in exercise was matched by an increase in obesity. As a physician, the author should recognize that correlation does not equality causality.  That is, it goes way too far to hang the increase in obesity on people exercising more.  In the first place, lots of people who have become more obese weren’t exercising at all, or exercised very little.  I certainly increased in obesity over that time period and I wasn’t exercising at all.  Further, some people may have exercised more and not changed their weight at all.

He explains this by stating that people who exercise stimulate their appetites “spurring them to eat more than they would have without working out.”  He apparently can’t comprehend that some people may nonetheless not eat back all the calories burned during the exercise. He argues that “[p]eople also assume that expending more energy necessitates higher calorie intake, but they often overestimate how much.”  And, he argues that the idea that exercise speeds up metabolism is exaggerated.  I don’t disagree that these arguments do apply to some people.  Yes, some people don’t really understand how many calories are in certain foods and have no idea of how many calories they burn.  And, I’m sure that some — maybe even most — people do eat back all the calories burned during exercise.  But, some and most aren’t all.

People engaged in serious weight loss efforts can be far more knowledgeable than he posits in his article.  In fact, an activity monitor like a Fitbit can help.  I personally count my calories at MyFitnessPal and my points at Weight Watchers.  MFP talks to Fitbit and tells Fitbit how many calories I’ve eaten.  I know perfectly well how many calories are in a cookie or an ounce of chips or a piece of chicken or half a cup of blackberries.  And, I also know the calories I burn during exercise because I’m using an activity monitor. I also know that my basal metabolic rate is about .9 calories per minute.  If I exercise 30 minutes and my Fitbit says I burned 150 calories, I know that my net added calories due to the exercise was about 123 calories.  Yes, I know that none of this is exact.  But, I’m not just guessing that because I exercise 30 minutes I can eat a 420 calorie Cinnamon Crunch Bagel either.

The author also points out that people’s basal metabolic rates drop as people lose weight, even if they engage in daily exercise.  Well, yeah.  Basal metabolic rate is the rate you burn calories just existing, doing nothing.  It goes down as you lose weight since your body is smaller and it takes less energy to sustain it.  I don’t think I have ever taken the position that exercising is going to have a profound effect on my BMR.  Rather, exercise primarily adds to the calories I burn during the time I’m exercising.

Malhotra then makes the point that it is “calorie intake that is really fueling the obesity epidemic.”  I actually agree with this point.  Of course, that is true.  However, that is entirely beside the point in arguing whether exercise can help weight loss.  Exercise can help weight loss, even if weight gain is largely fueled by excessive calorie intake.  I also agree with him that the “food and beverage industry is most guilty of perpetuating the false belief that the obesity epidemic is simply due to lack of exercise.”  Again, I don’t have to think that obesity is primarily caused by lack of exercise (which I don’t) in order for me to think that exercise can be a helpful addition to a weight loss program. And, I agree with him that poor diet contributes to disease and that “[y]ou can’t outrun a bad diet.”  I am a big believer in eating a healthy diet.

Sure, I believe that exercising alone is not going to cause sufficient weight loss for most people.  Cutting calories will also be needed.  And, of course, if you eat back all your calories earned through weight loss then the exercise didn’t increase your calorie deficit.  But, that is not the same as saying that exercise is useless for weight loss.

The author seems to accept as a given that every person will eat back every last calorie burned during exercise, because exercise stimulates appetite.  I think there are two primary problems with this.  Not everyone eats back every last calorie earning during exercise.  I certainly don’t.

Fitbit shows me my calorie deficit.

Fitbit shows me my calorie deficit.

I do think it is important to have a good understanding of how many calories you burn and how much you eat (I personally track it, but I recognize not everyone likes to do that).  For me, I eat pretty much the same calories on average during a week whether I exercise or not.  I do not eat back all my exercise calories.  But, my calorie deficit is far larger on the weeks that I exercise. No, not everyone is me.  Some people (maybe most) do eat back all their exercise calories.  The objection I have to the article is that the author doesn’t even seem to recognize that some people do achieve a greater calorie deficit through exercise.

The other problem that I see is that even if someone eats back every calorie burned during exercise, that could still help them lose weight.  How?  It could make the weight loss program more sustainable.  I personally average about 1200 calories a day and don’t find that really hard to do.  But, some people do find that hard to do.  Imagine someone who, without exercise, burns 1700 calories a day and eats 1200 calories a day, causing a 500 calorie a day deficit.  But, that person hates eating at that level and gives up on weight loss a week later.  Now, imagine that person starts exercising and burns an extra 300 calories a day and ups the calories eaten to 1500 calories a day.  That person now has a 500 calorie a day deficit, but finds the plan far more livable and stays on it.  Yes, that person ate back all the exercise calories, but is more successful because the plan has become sustainable.

As I’ve stated, there are things I agree with in the article.  I do think that obesity is primarily caused by increased calorie intake and I agree that people wanting to lose weight will do best if they reduce the calories eaten.  I also agree that there are many non-weight loss reasons to exercise and I agree that eating better food, including food with less sugar, is a good thing.  And, I do think that exercise can increase appetite and that if you eat calories equal to what you burned, then you don’t get any extra weight loss from increasing activity.  And, yes, the world is full of ignorant people who way overestimate the calories burned during exercise and way underestimate the calories they eat.

But, exercise can still help weight loss.  If you are knowledgeable about the calories you are taking in and are knowledgeable about the calories you burn (and a Fitbit can help you with gaining that knowledge), then exercise can be a valuable adjunct to weight loss.  Take off my Fitbit?  Not any time soon.


  1. says

    The article has me banging my head! Really exercise will not help losing weight!

    I do think it’s not the main factor to losing weight but I’m in the group of people that believe it does increase your metabolism. A well tune muscle burn more calories all day long (not just when we exercise). As you say, eating as much calories as you lost while exercising can still be a good strategy.
    Richard M. recently posted…Peanut Butter Banana BreadMy Profile

  2. Andrea says

    … and exercise reduces stress. I binge when I’m stressed, so exercise really works for me. I find that doing an average of 10,000 steps per day triples my rate of weight loss (1.2kg per week (ie 3 pounds) vs a measly 200-400g (which is around 1/2 to 1 pound) . Exercise doesn’t increase my appetite beyond what I can manage (I count weight watchers propoints). Probably when I’m not stressed and am seeing good results on the scale I’m much more able to stick to the program.

  3. says

    I like the saying, exercise is a wellness tool, not a weight loss tool. We all do need it! It aids health incredibly. But weight loss? Not so much. The studies show it actually slows down weight loss, because for one thing, if you gain muscle that’s weight GAIN! “Weight loss” is just too one-dimensional to capture the concept of fitness gain.

    But I agree that the scare tactics of the headline and article are disappointing.
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    • says

      I do think that the benefits of exercise are primarily wellness related, not losing weight related. I also think it is huge for weight loss maintenance. Still, for some people who are careful to keep a calorie deficit, I think that exercise can be one tool to help with weight loss. For me personally I’ve lost more weight when I was exercising regularly than when I wasn’t and I did eat more calories. I think this is just a complex issue, which has a lot of individual components to it.
      Kitty recently posted…Does Exercise Help Weight Loss?My Profile

      • says

        Good point, Kitty, and n=1, always. But here’s something to consider: what if that extra weight you lost from exercising (and greater calorie deficit) came from your body’s lean mass, which people like Volek & Phinney say it would? Meaning, you lost weight but it was muscle, not fat – and now you want to regain some muscle. This, again, underscores that simply measuring weight lost doesn’t really capture what you’re really trying to achieve. (Not suggesting this happened to you, there’s no way of knowing that without lean mass measurements pre and post.) Just a thought. All best.
        Wendy recently posted…Why did the chicken cross my plate?My Profile

        • says

          For women especially, gaining muscle through exercise is very slow – most women would be lucky to gain 1lb of muscle in a month! However, doing strength training can help to preserve the muscle that you already have. Dieting alone, and especially losing lots of weight quickly can cause some muscle loss as well as fat loss which just makes it more difficult to keep the weight loss later.
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          • says

            And, this is exactly why I just started working with a personal trainer for strength training. I want to preserve what muscle I have, while still losing fat. And, I also want to eventually build some muscle as well.
            Kitty recently posted…Does Exercise Help Weight Loss?My Profile

        • says

          I do think people have to be careful about losing too much lean mass. I keep track of my body fat (roughly) through my scale. I have lost some during the 56 pounds I’ve lost so far, but the greater majority of what I’ve lost has been fat. And, I’m doing the personal training now to try to preserve and build muscle mass.
          Kitty recently posted…Does Exercise Help Weight Loss?My Profile

  4. says

    Hi Kitty, Yes, I hate defeatist articles even more that have crazy promises. I know a bunch of people who have changed their ways and kept off pounds for several years. That is a fact –there is a real way to do that. We who have done that know it to be true.

    Exercise is often directly related to weight loss, though as you point out, it’s not because of all the calories burned, since it is usually a much smaller amount burned than people think.

    However, for me, exercise taught me to love myself more and treat myself better. When I practice self-love, I eat less junk food. When I exercise I remember how great my body is and that I need to protect that. The thought curbs the overeating more than how many calories are burned. 🙂
    Marion recently posted…One Day at a Time, One Hour at a Time, One Bite at a Time…My Profile

    • says

      No, no, not all. Nothing offensive in the least. I agree with you. It is really important to pay attention to the loss of muscle mass when losing weight. I’ve tried to do so throughout — with some success, but not entirely enough. That is the main reason to do the trainer.
      Kitty recently posted…Does Exercise Help Weight Loss?My Profile

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