Dietary self-selection patterns of rats with mild diabetes

Rats were allowed a free selection of a diet from among separate sources of protein, fat and carbohydrate or were fed a composite diet formulated to approximate the nutrient composition of a commonly used nonpurified diet. Immediately after streptozotocin injections, diabetic rats displayed polyuria, polydipsia and glycosuria as well as elevated fasting plasma glucose levels and glucose intolerance indicative of mild diabetes. Diabetic rats allowed a free choice tended to consume more protein and consumed significantly less carbohydrate than nondiabetics. This pattern of nutrient choice was associated with a reduction of diabetic signs including reduced polyuria, polydipsia and glycosuria. Diabetic rats permitted to choose their diets were not hyperphagic and maintained a slow but steady rate of body weight gain, accompanied by a sparing of body fat stores. In contrast, diabetic rats consuming the composite diet experienced no improvement in diabetic status; these rats displayed a deterioration of fasting plasma glucose, severe polydipsia, polyuria and glycosuria as well as hyperphagia and wasting of fat stores. These data demonstrate that when mildly diabetic rats are given the opportunity to select their own diets, they choose a diet that leads to improvement of their diabetic status.