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What Type of Exercise Is Best for Reducing Obesity?

Expert information on aerobic exercise, weight training, and more — plus tips for finding a routine you’ll stick to.

with David Creel, PhD, RD

Whether you want to lose just a few pounds or a bunch more, you may not find exercise all that appealing. It may, instead, seem easier to just go on a diet to quickly shave off the extra weight and forgo upping your activity level. But dieting often involves significantly depriving yourself of the quantity and types of foods you enjoy. In addition, the more restrictive a diet is, the more likely you’ll gain back whatever weight you lost (and maybe even more) once you go off the diet. That’s in part because your metabolism may slow when your food intake is very restricted, causing you to burn fewer calories than before.

If you have obesity, here’s what to know about how adding exercise to your routine may impact your weight loss.

Is aerobic exercise effective for obesity?

There’s no question it’s helpful, but it works best when you combine it with better food choices. The key to weight loss is burning more calories than you consume. For people with obesity, getting involved in aerobic exercise that burns a high number of calories can be an effective way to lose weight and also body fat. But here’s the hitch: It takes a lot of exercise to burn enough calories to create a deficit, explains David Creel, PhD, RD, director of exercise physiology and a psychologist in the Bariatric & Metabolic Institute at Cleveland Clinic. Generally, he says, it may be easier to decrease calories from your diet than to burn a large number of calories by exercising. For example, “A person with obesity will need to walk one to two hours to burn approximately 500 calories,” says Dr. Creel. “That same person could create the same calorie deficit by choosing broccoli over French fries at a meal.” 

On the other hand, Dr. Creel notes that “exercise can improve mood, sleep, and energy — improvements that may then lead to positive changes in eating.” In addition, research suggests that in the long-term, doing regular aerobic exercise may be the best predictor of who maintains their weight loss. According to Dr. Creel, people who maintain their weight loss “engage in, on average, 250 minutes per week [about four hours] or more of aerobic activity.” 

Which is more effective for obesity: high intensity or low/moderate intensity aerobic exercise?

Many studies have found that higher intensity exercise is more effective for losing not just weight but also body fat compared with lower intensity exercise. According to Dr. Creel, high intensity exercise burns more calories in a shorter time period than light or moderately intense exercise. “For example, people who exercise 200 minutes per week at a high intensity should lose more weight than those who engage in 200 minutes of light physical activity, assuming no difference in diet,” says Dr. Creel. In addition, after high intensity exercise your resting metabolism may remain substantially higher — and, therefore, your body continues to burn more calories — compared with lower intensity exercise, according to Dr. Creel. “People who do high intensity training typically get fit faster and may be able to expand their activities because of these improvements,” adds Dr. Creel.

But, high intensity exercise does come with an increased injury risk, and some people may not find it as pleasurable as lower intensity workouts. What’s important is choosing physical activities that can be done regularly over the long term. As Dr. Creel puts it, “regular moderate intensity physical activity is better than only occasional high intensity training.”

Some examples of high intensity exercise (aka vigorous exercise) are running, stair climbing, or hiking or biking uphill. Examples of low-to-moderate intensity activities include walking, biking on a flat surface, or using an elliptical machine at a low resistance setting.

What about weight training for obesity?

Most obesity research focuses on aerobic exercise because weight training (aka resistance or strength training) doesn’t burn as many calories. However, says Dr. Creel, when people lose weight, it’s not uncommon for a large part of that weight loss — some 25% — to be muscle tissue, which is what you don’t want to lose. “Since the amount of muscle we have influences how many calories we burn at rest, maintaining it is important,” says Dr. Creel. “Resistance training can help maintain more of this muscle.”

Research has also found that doing weight training three times a week for ten weeks resulted in a significant reduction in total body fat as well as fat around the abdomen, which is associated with an increased risk of diabetes and heart disease compared with fat around the hips. Weight training also adds variety to a workout routine, perhaps making it more likely that you won’t get bored. “The ideal situation is to combine the two [aerobic exercise and weight training],” says Dr. Creel. Plus, weight training has a number of other benefits.

Does exercise need to be done along with dieting or can it be effective on its own?

Since weight loss occurs when the number of calories burned is greater than the calories consumed, if you can exercise a lot, then you’ll be able to lose weight without also dieting. But, if you’re not very fit to start and you don’t have a lot of time to exercise, you probably should combine exercise with dietary restrictions. Plus, as mentioned above, it takes a whole lot of, say, walking to burn off even a few hundred calories. “It is unrealistic for most people to expect to lose weight and keep it off without altering their diet,” says Dr. Creel.

What can be done to increase the likelihood that a person will stick with exercise?

Making exercise a part of your day is important for maintaining a regular routine, says Dr. Creel. This might mean, for example, “walking instead of sitting when a child has soccer practice, walking while talking on the phone, or riding a stationary bike or using a treadmill when watching TV,” suggests Dr. Creel. 

Also key is finding activities that are enjoyable. “If exercise is not enjoyable, at least some of the time, it will be difficult to maintain a regular routine,” adds Dr. Creel. You need to choose activities and situations that work for your needs. For example, while some people prefer group exercise classes or activities with built-in socialization, like a hiking club, others enjoy working out in solitude — whether that’s at a gym, in their home or yard, on a local walking or biking path, or elsewhere.       

Are there safety concerns for exercising with obesity?

If you have obesity and you want to start an intense exercise program, you should first talk with your physician, suggests Dr. Creel. “Obesity increases the risk for cardiovascular disease, diabetes, and high blood pressure, conditions that [in turn] can increase the risk for exercise-related problems, especially if the exercise is intense.” In addition, excess weight can put undue stress on various body parts — including the knee, hip, and foot — which could result in overuse or other injuries, notes Dr. Creel. So, it might be best to start with low-impact activities, such as brisk walking outdoors, cycling (outside or on a stationary bicycle indoors), treadmill walking, or working out on an elliptical trainer.