Why was this study done?

Two of the keys to a successful weight loss program are a low-calorie diet and increased exercise. These two strategies are often combined without understanding the effects of each individual part. This study was designed to separate a low-calorie diet from aerobic conditioning to determine which has more effect on weight loss. The study tested diet alone, exercise alone, and diet and exercise to determine which produced the best results. Exercise consisted of aerobic conditioning (walking/running) for 30 minutes, five days a week. The low-calorie diet consisted of meal replacement for two meals a day (210 calories each) and a healthy meal for the third meal.

What did the study find?

The study found that diet and exercise combined had the greatest effects on weight loss and the greatest improvements in aerobic health (VO2 max) and blood lipids (triglycerides, VLDL in males, and lower triglycerides in females) when compared to diet alone and exercise alone.

The effects of aerobic conditioning and/or caloric restriction in overweight men and women
Authors: Hagan RD, Upton SJ, Wong L, Whittam J. Med Sci Sports Exerc. 1986 Feb;18(1):87-94.
PubMed Citation PMID: 3457234.
PDF Manuscript: Med Sci Sports Exerc, 1986.