If your goal is to lose weight, does one approach have an edge?

When it comes to getting the number on the scale down, everyone is searching for the one perfect solution. Is diet the answer or is it exercise? Spoiler alert: What and how much you eat has a far greater impact on weight loss than how much you exercise, although working out is undeniably beneficial. Here’s how it breaks down:

The Case for Diet

• Calories count. It’s amazingly difficult to “exercise away” excess calories, says Karen Ansel, MS, RDN, author of Healing Superfoods for Anti-Aging. For example, to work off about 300 calories, a 160-pound person needs to walk for an hour at quick, 3.5-mph clip. Or they could just swap sweetened beverages for plain water, coffee or tea at each meal.
• So do nutrients. What you eat also makes a difference. “Protein takes more energy to digest than carbs or fat. Eating plenty of protein-rich foods fires up your calorie burn,” says Ansel. Consuming more fiber helps, too, as it fills you up for fewer calories and may help “shuttle” some fat calories out of your body undigested, she adds. 
• Portions are key. Eating even a little bit less automatically lowers your calorie intake, which is obvious, but often overlooked. “Just by leaving a few bites over at each meal, you can trim 10 to 20 percent of your daily calories,” says Ansel.

The Case (Sort of) Against Exercise

• It increases appetite. A 2013 study in the International Journal of Epidemiology found that the more you exercise, the more you may eat later. Two factors are at play: when you work out, your body legitimately craves more food to boost energy. Plus, you feel like you “earned” that extra helping.
• It has diminishing calorie-burn returns. A 2016 study in Current Biology found that our bodies adjust to keep energy levels—how many calories you need—more or less even. Put simply, “as you do the same workout over and over, your body becomes more efficient, and you burn less each time,” says Robert Steigerwald, MS, a registered clinical exercise physiologist in New York.

But exercise is still very important

While exercise won’t by itself help you lose weight, it’s vital to your health. “Regular exercise lowers blood pressure, improves cardiovascular health, strengthens bone and helps prevent injury as you age,” says Steigerwald. Plus, if you are trying to lose weight, pumping up your workouts, particularly weight training, which builds muscle and may jump-start metabolism, can nudge you past plateaus. Studies also show that people who’ve lost weight keep it off if they exercise most days of the week.

Bottom line: While you can’t out-exercise a bad diet, you need exercise to fine-tune a body made healthier by a good diet.