A controlled trial of reduced meal frequency without caloric restriction in healthy, normal-weight, middle-aged adults1,2,3
Kim S Stote, David J Baer, Karen Spears, David R Paul, G Keith Harris, William V Rumpler, Pilar Strycula, Samer S Najjar, Luigi Ferrucci, Donald K Ingram, Dan L Longo and Mark P Mattson
1 From the Beltsville Human Nutrition Research Center, US Department of Agriculture, Agriculture Research Service, Beltsville, MD (KSS, DJB, KS, DRP, GKW, and WVR), and the Clinical Research Branch (PS and LF), and the Laboratories of Cardiovascular Science (SSN), Experimental Gerontology (DKI), Immunology (DLL), and Neurosciences (MPM), National Institute on Aging Intramural Research Program, Baltimore, MD
Background:Although consumption of 3 meals/d is the most common pattern of eating in industrialized countries, a scientific rationale for this meal frequency with respect to optimal health is lacking. A diet with less meal frequency can improve the health and extend the lifespan of laboratory animals, but its effect on humans has never been tested.
Objective:A pilot study was conducted to establish the effects of a reduced-meal-frequency diet on health indicators in healthy, normal-weight adults.
Design:The study was a randomized crossover design with two 8-wk treatment periods. During the treatment periods, subjects consumed all of the calories needed for weight maintenance in either 3 meals/d or 1 meal/d.
Results:Subjects who completed the study maintained their body weight within 2 kg of their initial weight throughout the 6-mo period. There were no significant effects of meal frequency on heart rate, body temperature, or most of the blood variables measured. However, when consuming 1 meal/d, subjects had a significant increase in hunger; a significant modification of body composition, including reductions in fat mass; significant increases in blood pressure and in total, LDL-, and HDL-cholesterol concentrations; and a significant decrease in concentrations of cortisol.
Conclusions:Normal-weight subjects are able to comply with a 1 meal/d diet. When meal frequency is decreased without a reduction in overall calorie intake, modest changes occur in body composition, some cardiovascular disease risk factors, and hematologic variables. Diurnal variations may affect outcomes.
Key Words: Caloric restriction • meal frequency • intermittent fasting • cholesterol metabolism • blood pressure • controlled diet • normal-weight adults