Exercise Alone Is Not Enough for Weight Loss

We promote exercise at every opportunity with good reason. Exercise is the number one thing you can do to start improving your health today, unless you’re a smoker. If that’s the case, the first best thing you can do is quit smoking — and also start exercising.

The benefits of regular exercise are both invaluable and wide ranging. Exercise has been shown to:

  • help with weight control
  • reduce risk of heart disease
  • help manage blood sugar and insulin levels
  • improve mental health and mood
  • keep cognitive skills sharp
  • strengthen bone and muscle
  • reduce risk of some cancers
  • reduce risk of falls
  • improve sleep
  • improve sexual health
  • increase chances of living longer

That’s a whole lot of benefits right there, backed up by a whole lot of research. Lately, though, it’s starting to look like we might have to hang an asterisk on that first bullet point.

Exercise and weight control

The classical model of body weight goes like this: Calories come in and calories go out. If we eat more calories than we burn, we gain weight. If we burn more calories than we eat, we lose weight.

So, thinking logically, one would assume that burning more calories by increasing the amount we exercise would lead to a daily calorie deficit, and thus weight loss.

And that’s true to an extent. It does work. But an increasing number of studies are showing us why it doesn’t always work as well as we’d like.

First of all, exercise accounts for only a portion of the calories we burn daily. When we take into account our daily basal metabolic rate, thermic energy expense, and our general lifestyle activities, we may already be burning 1,500 or 2,000 or 2,500 calories or more. If we hop on a treadmill for a quick run after work, we might add another 400 calories, more or less, to our day.

That’s less than one plain bagel with cream cheese, or four slices of bacon, or a couple of Snicker’s bars. And after a hard workout, we’re going to want to eat something

So it’s difficult to create much of a calorie deficit through exercise for two reasons: 1) moderate exercise doesn’t add a whole lot relative to our normal daily calorie burn; and 2) when we do exercise, we tend to make up for the calories we burn by eating more calories.

Now that’s kind of basic, and it makes sense, but things do start to get complicated.

There’s the idea of metabolic compensation, for example. Some studies have shown that exercise does not add as much as expected to the total daily calorie burn. For example, burning 500 calories on a treadmill might only increase the daily total by 300 calories. Two possible reasons have been proposed for this: either the exerciser subconsciously compensates for exercise by slowing down their other activities during the day, or their underlying basal metabolic rate actually decreases on its own in response to exercise.

Some researchers even propose that this metabolic compensation could result in a maximum possible calorie burn, meaning that daily calorie burn totals could plateau after a certain amount of exercise. Exercising beyond that amount will not increase the daily total.

One interesting study gives support to this idea. Researchers tracking the calorie burn of very fit, highly active hunter-gatherer tribesmen in Tanzania were surprised to find that the daily calorie burn of these people did not differ much from the average modern American or European.

What does this mean for weight loss?

Traditional formulas for determining a person’s total daily calorie burn were difficult enough. These new concepts could mean those formulas are even less accurate than previously thought.

Exercise remains very important for overall health. But when it comes to weight control, it more and more seems as if the “calories out” portion of the “calories in = calories out” equation is much harder to change, and much less affected by exercise.

That leaves us with “calories in,” and that’s where things are truly out of balance these days.

Modern agriculture and agricultural policies have created a rich abundance of food. But unfortunately, this abundance is often tilted toward foods that are easy, cheap, high in calories, and poor in overall nutrition. We are surround by temptation, and it’s all too easy to find ourselves eating something that seems like just a light snack, but it’s really adding 1,000 calories to our daily balance.

There’s no easy solution. We need to educate ourselves on what we’re eating, how much of it we’re eating, and what the consequences are. Short of adjustments to government policies that have led to the proliferation of these cheap, low-nutrition foods, we need to do all we can to consciously avoid them. Count our calorie intake if necessary, close our eye when we pass the displays at the check-out counter, don’t buy snack food from gas stations — do whatever it takes to restrict calorie intake in a way that is sustainable and healthy. It’s not a diet, it’s a lifestyle.

Oh, and keep exercising. That’s really important.