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.
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.