Insulin increases the daily food intake of diabetic rats on high and low fat diets

The effects of insulin dose and diet composition on daily food intake were investigated by IV infusion of insulin in doses of 2 to 5 U/day into diabetic rats consuming either a high CHO or high fat diet. The daily food intake of the diabetic rats on both diets increased significantly over baseline levels ( p < .01) at the low insulin doses and was maintained at these elevated levels through the 5 U/day dose. Insulin increased the rate of weight gain from 1g/day during baseline to 2 and 2.5 g/day in high CHO and high fat fed diabetics ( p < .01). These results show that treatment of diabetic rats with continuous low doses of IV insulin results in a 40% increase in daily food intake regardless of the diet consumed and this increase is accompanied by an increase in rate of body weight gain. While the high fat fed diabetics were relatively hypoglycemic, these increases in intake are not the result of insulin-induced hypoglycemia, since blood glucose concentrations are significantly elevated when the increases occur at the lower insulin doses ( p < .01). Thus, peripheralinsulin infused at physiological levels stimulates rather than inhibits daily food intake.