Effects of Intermittent Feeding on Rat Adipose Tissue and Diaphragm Metabolism

Abstract

Effects of intermittent feeding were studied in rats fasted and fed for alternating 3-day periods. After 30 days, rats were sacrified and food intake, weight gain and carcass lipid measured. Fat pads and hemidiaphragms were incubated with U-¹⁴C-glucose or 1–¹⁴C-palmitate. Oxidation and incorporation into tissue lipids were analyzed. Compared to rats fed ad libitum, intermittently fed and fasted animals ate 50% less food, gained 75% less weight and had greater carcass lipid content per gram of weight. Glucose incorporation into lipid was increased in diaphragm and adipose tissue, but oxidation and incorporation into glycogen were increased only in the latter tissue. Palmitate oxidation was unchanged in either tissue, but incorporation into adipose tissue lipid fractions was increased. Conclusions are that intermittent feeding reduces caloric efficiency, stimulates lipogenesis and glucose oxidation, and results in a relative excess of body fat even in the presence of undernutrition.