Fewer calories or more exercise: Which is best for weight loss?

A study in The Journal of Clinical Endocrinology & Metabolism reveals that dieting alone is as effective at reducing weigh and fat as a combination of diet and exercise — as long as the calories consumed and burned are equal.

There was one important difference, however.

Here are the details.

  • 35 overweight but otherwise healthy adults randomly assigned to follow one of 3 diet and exercise combinations over 6 months
  • Group 1 followed a healthy diet designed to maintain the participants? bodyweight
  • Group 2 followed a diet that reduced their caloric intake 25% (550 and 900 fewer calories per day)
  • Group 3 reduced their calorie intake by 12.5% while increasing physical activity to achieve an additional 12.5% increase in calorie expenditure

And the results.
Groups 1 and 2 lost about 10% of their body weight, 24% of their fat mass, and 27% of their abdominal visceral fat. The distribution of the fat in the body, however, was not altered by either approach.

There was one difference: Including exercise (Group 3) improved aerobic fitness.

The researchers concluded, “Exercise therefore, plays an equivalent role to caloric restriction in terms of energy balance; however, it can also improve aerobic fitness, which has other important cardiovascular and metabolic implications.”

1/29/07 21:50 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.