The truth about exercise and weight loss
When you want to lose weight, there are two things you do: eat less and exercise more.
Just cutting calories should cause you to drop pounds. But exercise alone is rarely enough for weight loss. Life isn’t fair, after all.
Think of it this way: When going on a 30-minute brisk walk at about 4 miles per hours (that’s a 15-minute mile), a 155-pound person burns about 167 calories, according to Harvard Medical School. Want to celebrate your accomplishment? That exercise is quickly erased by a large scoop of vanilla ice cream or two small chocolate chip cookies.
If more serious exercise is your thing, 30 minutes of vigorous stationary bicycling burns 391 calories. But that gets wiped away with one slice of pepperoni pizza.
It doesn’t seem fair how all that effort can be nullified by a few bites of tasty food.
Is more exercise the answer?
It seems like simple math: If exercising for x minutes burns y calories, then just exercise longer and burn more calories. But research shows it’s not that easy.
Recently, New Scientist explained it with a story called, “Why doing more exercise won’t help you burn more calories.” Science writer Teal Burrell explored the idea of the so-called exercise paradox. People who dramatically increase their workout regimens often find that despite all the sweat and motion, they shed few pounds. Scientists have several theories why that might happen.
They eat more. You went for a grueling hike and are so proud of yourself, so you reward yourself later with a chocolate shake. People tend to overestimate the calories they burn when they exercise. In one study, people worked out on a treadmill and then were told to eat from a buffet the amount of food that equaled the calories they thought they burned. They guessed they had burned about 800 calories and ate about 550, when they had really burned just 200.
They move less. You went on that grueling hike in the morning, so you sprawled on the couch the rest of the day. Another theory is that people make up for their workouts by spending the rest of the time being sedentary. These are called “compensatory behaviors” when the moving and not moving balance each other out. But exercise physiologist Lara Dugas of Loyola University doesn’t buy this idea. “That doesn’t mean you lose that 500-calorie run because you’re sedentary for the rest of the day,” she tells New Scientist. “That doesn’t make sense.”
The body adapts. The theory that seems to make the most sense is that when you exercise more, your body adjusts by spending less energy on internal functions, from the immune system to digestion. Those systems that are working in the background, spending calories, just become more efficient when you exercise more, researchers think.
The role of exercise
Mathematician and obesity researcher Kevin Hall explained to Vox why adding more exercise probably won’t lead to much weight loss. Hall used the National Institutes of Health’s Body Weight Planner to calculate that if a 200-pound man added 60 minutes of medium-intensity running four days per week for a month while keeping his calorie intake the same, he’d lose five pounds. “If this person decided to increase food intake or relax more to recover from the added exercise, then even less weight would be lost,” Hall added.
So if someone is trying to lose a lot of weight, it would take a lot of time and effort to try to lose pounds based on exercise alone.
But of course, that doesn’t mean you should cancel your gym membership and toss your sneakers into the back of your closet. Exercise is still a key part of the one-two punch to weight loss. You just have to combine it with calorie control.
Nutritionists will say that weight loss is about 80% diet and 20% exercise. So yes, watch the brownies and the snacks if you’re trying to lose the love handles, but keep moving. It’s an eat-move combination that does require smart eating and regular movement to be healthy. Sometimes being fit just doesn’t seem fair. But it’s worth it.
The truth about exercise and weight loss
Eating less is more important than exercise if you want to lose weight.