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Health Myths Debunked: Does Exercise Really Help You Lose Weight?

Kayla Reynolds, MS

With the New Year in full swing, you’re likely bombarded with ads about the newest promising diet and your inbox is flooded with companies trying to sell you waist trainers or exotic extracts guaranteeing to help you reach your weight loss goals. At Noom we’re in the business of helping you navigate the confusing world of weight loss and health — with science!

Have you ever heard someone say “you can’t out-exercise a bad diet” or “it’s 90% diet and 10% exercise?” Let’s take a look at how exercise fits into the weight loss equation.

The Myth

Exercise helps you lose weight.

The Background

Exercise burns calories. In order to lose weight, you need to burn more calories than you take in, so it would only make sense that exercise helps you lose weight.

The Facts

Physical activity has a number of benefits! It can help increase your energy levels, boost mood, improve body composition, and reduce your risk of developing chronic conditions or health complications. Unfortunately, studies actually show very little difference in weight loss between people who modify their diet and exercise and people who change their diet alone. However, long-term weight loss is greater when diet and exercise are combined, which suggests that exercise might play a more important role in weight maintenance.

There are a number of reasons that exercise does not directly influence weight loss per se:

  1. People often overestimate the number of calories they burn while exercising.
  2. Most people overcompensate for the calories they do burn through activity by eating more (either subconsciously because they are hungrier, or by justifying eating certain foods since they worked out).
  3. Some people become less active the rest of the day, burning less calories overall than they would have had they not “exercised.”
  4. You can easily eat hundreds of calories in minutes, but depending on the activity, it can take hours or more to burn these calories.

For these reasons, adjusting your calorie intake has proven more successful in helping people shed unwanted weight.

The Bottom Line

You can’t “exercise out a bad diet,” and exercise likely plays a more important role in weight maintenance than in weight loss. That being said, there are a number of other reasons to get moving!

  • Clint Johnson

    So poorly thought out exercise habits don’t compensate for poorly thought out eating habits? And this is news?

    Understand the number of calories your exercise burns. Understand the amount of calories in your food so that you do not use the exercise as an excuse to consume more calories than you burn. Do not increase sedentary activities to more than offset your exercise. Find which is easier for you; increasing your calorie expenditure, or decreasing your calorie intake. It is a sliding scale, but you have to track it and make sure the math works out.