The health consequences of eating one large meal a day compared with eating three meals a day has not been established. Now two recently published journal articles are among the first to report the effects of meal skipping on key health outcomes, based on a study involving a group of normal-weight, middle-aged adults.

The study analyses were authored by scientists at the Agricultural Research Service (ARS) Beltsville Human Nutrition Research Center in Beltsville, Md., and colleagues at the National Institute on Aging (NIA) Intramural Research Program in Baltimore, Md.

For the study, a small group of male and female volunteers participated in two eight-week meal-treatment periods. The study's crossover design meant that each volunteer completed both of the treatment diets, enabling them to serve as their own controls.

Volunteers were divided into one of two groups during each treatment period. They consumed either all of their required weight-maintenance calories in one meal a day or in three meals a day. ARS physiologists David Baer and William Rumpler and NIA neuroscientist Mark Mattson designed the study.

The first study analysis showed that consuming a one-meal-per-day diet, rather than a traditional three-meal-per-day diet, is feasible for a short duration. It showed that when the volunteers were "one-mealers," they had significant increases in total cholesterol, LDL "bad" cholesterol and in blood pressure, compared to when they were "three-mealers."

The changes in cardiovascular disease risk factors occurred despite the fact that the one- mealers saw slight decreases in their weight and fat mass in comparison to when they were three-mealers. Those findings were published in the April 2007 issue of the American Journal of Clinical Nutrition.

Further analysis of the study group showed that when the volunteers were one-mealers, they had higher morning fasting blood sugar levels, higher and more sustained elevations in blood sugar concentrations, and a delayed response to the body's insulin, compared to when they were "three-mealers." Insulin is required to lower blood sugar levels. Those findings were published in the December 2007 issue of Metabolism.

ARS is the U.S. Department of Agriculture's chief scientific research agency.