Optimal diet for glycemia and lipids.

Concentrations of glucose and lipids in the blood have important health implications and are influenced by dietary intake. Dietary intake and energy expenditure regulate body weight, which is also an important determinant of health. Thus it would be important to determine the optimal diet for affecting blood glucose and lipids and body weight. Many professional health organizations in different countries have made dietary recommendations that include caloric restriction when needed to prevent or reverse overweight or obesity, limitation of saturated and trans fat, and emphasis on fruits and vegetables. These professional groups have not recommended extremely low carbohydrate or extremely low fat diets, despite much popular interest and recent research in these approaches. In several clinical trials, diet and exercise interventions prevented or delayed the development of type-2 diabetes. These trials showed the value of diet interventions, but did not attempt to determine which dietary approach was optimal. Clinical trials attempting to determine the optimal diet suffer from small sample sizes, short follow-up, and poor follow-up of participants. Therefore, the optimal balance between the total fat and carbohydrate contents and the optimal types of fats and carbohydrates remain unknown.