Why Exercise Alone Won’t Help You Lose Weight

Why Exercise Alone Won’t Help You Lose Weight


We all “know” that in order to lose weight, you have to consume fewer calories.

We have known that since 1958 when scientists told us so.

We “know” that when the treadmill tells us we burned 3,750 calories, we have burned one pound of fat.  But is this really what’s happening?

The problem with this concept is that our bodies are much more complicated.

You would expect that if you kept your diet the same and carefully calculated your calories burned, when you hit 18,750 calories, you’d be five pounds lighter.

This would be the equivalent of a 200-pound man running 60-minutes a day, four times a week.

In a month he should be five pounds lighter.

But why doesn’t it work that way?

Well, there are three ways your body expends energy:

  • Basal metabolic rate – what we often refer to as our metabolism. This is the basic energy required to function.  This is about 60-80% of our energy expenditure.
  • Energy required to break down food. Our digestion requires calories, and this is approximately 10% of our daily calorie use.
  • This is the energy used in physical activity.  10-30% of calories burned depends on this.

A 10% increase in calorie usage is nothing to ignore, but it’s not nearly equal to food intake, which is 100% of the energy intake into the body. Exercise will only make small changes in your overall weight.

This is not to say that exercise is not important to your overall health.  It plays a big part in your well-being, including controlling your blood pressure and triglyceride levels.

But while there may be statistical significance, you can’t control your weight solely through exercise.

‘The Biggest Loser’ showed this clearly.  While the contestants worked out hard, it was those who ate the fewest calories who won.

And unfortunately, it also slowed down their basal metabolic rate, which is why so many of them quickly regained the weight they had lost.  For more information about this phenomenon, read here. (Link to Biggest Loser Article)

We have little control of our basal metabolic rate, even though it is by far our biggest use of calories.

What this means is:  What we eat is 100% of energy in, so exercise is only going to account for 10% of our energy out.

Using the simplistic model of calories in/calories out is not going to help much in our weight loss journey.

What we eat is going to be the biggest factor that we can control.

Calorie restriction alone works better than diet and exercise combined, according to an article published in the Journal of the American Medical Association in April 2006, which studied 48 sedentary people for six months.

What’s hard for most of us to accept is that exercise might actually work against us.

Too many of us think that because we burned 1,000 calories, we are now free to eat a 1,000 calorie donut and our weight will remain the same.

But when you realize that only 10% of the calories burned results in weight loss, we have actually eaten 900 more calories than we burned.

This is what gets so many of us into trouble with exercise.  We think we can eat more than we should based on a calories in/calories out model.