The "Fidget Factor" in Weight Control

Why do some people seem to be able to eat whatever they want and not gain weight? According to researchers at Mayo Clinic in Rochester, MN, it is because they burn hundreds of calories throughout the day by fidgeting. This fidget factor, known as nonexercise activity thermogenesis (NEAT), includes behaviors such as crossing or uncrossing the legs, bobbing up and down, stretching or standing up often, maintaining good posture, or just being generally restless.

In a study of 16 people who were fed 1,000 calories per day in excess of weight-maintenance requirements for 8 weeks, two-thirds of the increases in total daily energy expenditure were due to increased NEAT. "When people overeat, NEAT switches on in some people to 'waste' this excess energy," says Michael Jensen, M.D., an endocrinologist and one of the investigators. "Conversely, the failure to switch this on allows the calories to be stored as fat."

The researchers measured three main factors contributing to energy expenditure: basal metabolic rate (BMR—resting the body), postprandial thermogenesis (digesting, absorbing, and storing food), and physical activity (sports/fitness activities and NEAT). Overall findings showed that approximately 33 percent of the 1,000 extra calories consumed were burned by NEAT. Of the remaining calories, approximately 39 percent were deposited as fat, 4 percent were deposited as other body tissue, 8 percent were burned by BMR, and 14 percent were due to postprandial thermogenesis. Accelerometers and blood chemistry tests were used to measure energy expenditure in the study participants, who were between the ages of 25 and 36, were nonobese, had sedentary jobs, and did not engage in regular physical activity. Weight gain in the 16 participants varied from 2 to 16 pounds, with an average of 10 pounds gained in the 8-week study period. Those with the greatest increase in NEAT gained the least amount of fat. This suggests that by activating NEAT, individuals may burn calories that could help in the battle against obesity.

The study was published in the January 8, 1999, issue of Science Magazine, which can be found on the Web at www.sciencemag.org.