The calorie tracker on your treadmill, the fitness instructor who says you “deserve” an extra slice of pizza after spin class, and high intensity workout trends can lead you to believe that exercise is the best way to work off calories and excess weight. But according to new research, it may not actually be helping with weight loss after all.
Here’s one issue: Are those trackers even accurate? Studies show that wearable devices tend to either overestimate or underestimate energy expenditure by as much as 30%! So subtracting the estimated amount of calories you’ve burned from your daily calorie consumption goal can really throw you off.
Everyone has a “sweet spot” for exercising -- once you exceed the level of exercise intensity, duration and frequency that’s optimal for you, your body’s energy expenditure (the amount of calories your body burns during general functioning, physical activity, and digestion) stops increasing. Basically, our bodies reach a threshold where working out more does not necessarily burn extra calories.
On top of this, the calories we burn during exercise are not the same as the ones we eat. Exercise’s effect on our body involves many processes, such as breaking down and building up muscle. And this process only accounts for 10-30% of our daily calorie burn.
Our basal metabolic rate, or BMR, burns the most calories in our body every day, between 60-80%. BMR is the amount of calories our body expends everyday to keep us functioning well, like breathing, digestion and regulating heartbeat. BMR is another part of our body’s identity - things like our age, sex, and muscle mass factor into how high or low it is. While age and sex are factors we generally can’t modify, muscle mass is one factor we do have control over.
Research shows that anaerobic exercise, like strength training, may indirectly increase your BMR over time because of increased muscle mass. However, aerobic cardiovascular exercise does not increase how many calories your body burns at rest. So while some types of exercise can have a long term effect on the amount of calories your body will burn at rest, running for an hour certainly won’t “eliminate” the 1,000 calorie milkshake or 700 calorie margarita you had earlier.
The only true way to start and continue to lose weight is by reducing your daily calorie intake with a healthy, balanced diet.
Of course, this doesn’t mean you should stop exercising! Exercise does amazing things for your physical and mental health. It reduces your risk for diabetes, certain types of cancer, heart disease, and symptoms of depression and anxiety. In fact, exercise becomes more important AFTER weight loss because it functions to help maintain your current weight, and keep off the pounds you lost.
So what’s the bottom line? If you’re trying to lose weight: