Can You Lose Fat Through Exercise Alone?

One of the hardest parts about starting a fat-loss program is knowing you won’t be able to eat a lot of the foods you enjoy. At least, not in the same quantities. For this reason, some people try to achieve their fat-loss goal through exercise alone, hoping they’ll burn enough calories during their workout to make up for poor diet choices.

First of all, exercise tends to increase appetite, says Tiffany Chag, RD, a sports dietitian at the Hospital for Special Surgery in New York. If you’re not paying attention to what and how much you’re eating, you could take in more calories per day than you were getting before you even started your exercise program. “We don’t really realize we’re doing it,” Chag says. Over time, this could lead to stalled results or even weight gain.

In a recent study, a group of lean, overweight and obese women followed an eight-week exercise-only program. Not only did the women see zero fat reduction, but appetite hormone levels increased significantly in overweight and obese participants. These hormonal changes could explain the lack of fat-loss results, according to researchers.

In addition, exercise only burns a small percentage of calories in the overall scheme of things. A vigorous 30-minute strength session, for example, only burns roughly 223 calories for a 155-pound person, according to Harvard Health. That’s the approximate equivalent of a couple of tablespoons of olive oil or a protein bar.

Granted, exercise — and strength training, in particular — will have you burning calories long after your workout is over, but it may not be as much as you think. “People often get a false sense of how many calories they’re actually burning [during exercise],” says Steve Moore, MS, lead physiologist and health coach with the Penny George Institute for Health and Healing LiveWell Fitness Center at Abbott Northwestern Hospital.

All too often, we assume we’re burning more calories than we actually are, which makes it easier to reach for higher calorie foods. In fact, we can overestimate the calories burned by as much as four times the actual amount, leading us to eat 2–3 times our caloric expenditure from that workout, according to the results of a study published in the Journal of Sports Medicine and Physical Fitness.

In other words, just because the display on the treadmill or elliptical says you burned 300 calories, doesn’t mean you actually did: “Those [machines] are notorious for being wrong,” Moore says.

You might lose fat through exercise alone, but you’ll have far greater success if you pair your exercise with a healthy diet.

In a study published in Obesity, overweight and obese postmenopausal women who followed a combined diet and aerobic exercise program lost more weight over the course of one year than women who followed a diet- or exercise-only program. Still, the women who followed the diet-only program lost significantly more weight than the exercise-only group (8.5% versus 2.4%), and only slightly less than women who followed the combined program (8.5% versus 10.8% for the combined approach).

Don’t think you have to completely overhaul your diet or add crazy amounts of exercise to see results. Set achievable goals, like adding one extra serving of vegetables per day or taking the stairs instead of the elevator, and focus on meeting those goals for a few weeks before adding in other changes, Chag says. “[Your goal] has to be something that’s measurable, but set the bar so low that you can’t fail.”