Can vegetarian diets help to rein In the obesity epidemic?

Overweight and obesity are major health problems, not just in the United States but worldwide. More than 60 percent of adults in the United States are overweight, and 30 percent are obese. Worldwide, more than 1.2 billion people are overweight or obese. Vegetarians tend to have lower body weights than nonvegetarians. A review of the scientific literature found that 29 out of 40 studies of vegetarians showed that vegetarians weighed significantly less than non-vegetarians. This was true for both men and women, for African Americans, Nigerians, Asians, and other groups. Nine small studies also showed that vegetarians weighed less than non-vegetarians, but the difference was not statistically significant.

Vegetarian women average between 6 and 23 pounds lighter than non-vegetarian women, while vegetarian men are an average of 10 to 28 pounds lighter. Generally, vegans have the lowest body weights, followed by lacto-ovo vegetarians, then by near vegetarians (eating meat or fish less than once a week) with meat eaters having the highest weights, on average. These differences in weight persist even when cigarette smoking is controlled for. Possible explanations for weight differences include lower calorie and fat intakes and higher fiber intakes by vegetarians. Vegetarian diets have also been successfully used for weight reduction.

Berkow SE, Barnard ND. 2006. Vegetarian diets and weight status. Nutr Rev 64:175-88.