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You Exercise Faithfully... Why Aren’t You Losing More Weight?

New Study Shows It’s Primarily Because You’re Eating More
Released: Tuesday, June 25, 2019

Corby Martin

Baton Rouge, Louisiana -- It's well-known that people don’t lose as much weight as expected by exercising. A new study, led by Drs. Corby Martin and Tim Church, identifies why.

"The primary reason?  Physical activity, over the long term, makes us eat more," said Dr. Martin, director of the Ingestive Behavior, Weight Management, and Health Promotion Laboratory at LSU's Pennington Biomedical Research Center.

The difference between the amount of weight loss predicted from calorie-burning exercise and the actual amount of weight loss is known as compensation.  Compensation has been a focus of research for many years, and previous studies found that exercise results in only about 40 percent of the amount of weight loss expected.  

The new study by Pennington Biomedical looked at people who were overweight or had obesity over a six-month period.  Participants were placed into three groups:

  • A control group that did not increase physical activity levels
  • A low-dose group that did about 90 minutes of vigorous aerobic exercise per week
  • A high-dose group that did about 210 minutes of vigorous aerobic exercise per week

The researchers found that compensation took place in both of the exercise groups, but it was larger in the high-dose group that did 210 minutes of exercise per week.  Compensation was common in both groups, with 76 percent and 90 percent of participants compensating in the low-and high-dose groups, respectively.  Interestingly, almost half of the participants in the low-dose group did not lose any weight or gained weight, compared to only a quarter of the high-dose group.

One of the main findings from the study is that the reason for compensation is increased food intake.  Levels of activity outside of the structured exercise did not change, but people in the exercise groups experienced an increase in energy (food) intake.  Specifically, the low- and high-dose groups increased energy intake by 91 and 124 calories per day, respectively. 

"This increase really adds up over time, and it diminishes the effect that calorie-burning exercise has on body weight," Dr. Martin said.

The findings from this study have important health implications for people who wish to manage their weight.  For example, the findings indicate that, in order to reduce compensation and maximize weight loss from exercise, people need to focus on their food intake and avoid the increase that can occur with long-term exercise.  Nonetheless, exercise alone might not produce the amount of weight loss desired.

Therefore, Dr. Martin stressed that "If significant weight loss is the goal, it is best to follow a healthy diet and exercise program under the direction of a health professional."

"Once weight is lost, watching what you eat is an important part of keeping the weight off, and high doses of exercise also help promote long-term weight-loss maintenance," Dr. Martin added.

"Effect of Different Doses of Supervised Exercise on Food Intake, Metabolism and Non-Exercise Physical Activity: The E-MECHANIC Randomized Controlled Trial" was published in The American Journal of Clinical Nutrition.

The research was supported in part by the National Institutes of Health via the National Heart, Lung, and Blood Institute under award numbers R01HL102166 and F32HL123242; National Institute of Diabetes and Digestive and Kidney Diseases under award number P30DK072476, which funds Pennington Biomedical’s Nutrition Obesity Research Center; and the National Institute of General Medical Sciences under award number U54GM104940, which funds the Louisiana Clinical and Translational Science Center.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

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About the Pennington Biomedical Research Center

The Pennington Biomedical Research Center is at the forefront of medical discovery as it relates to understanding the triggers of obesity, diabetes, cardiovascular disease, cancer and dementia. The Center conducts basic, clinical, and population research, and is affiliated with Louisiana State University. The research enterprise at Pennington Biomedical includes over 450 employees within a network of 40 clinics and research laboratories, and 13 highly specialized core service facilities. Its scientists and physician/scientists are supported by research trainees, lab technicians, nurses, dietitians, and other support personnel. Pennington Biomedical is located in state-of-the-art research facilities on a 222-acre campus in Baton Rouge, Louisiana.