Type 2 diabetes is characterized by high and highly variable levels of glucose in the blood. The most serious consequence of long-term high glucose levels is that the excess glucose tends to bind to proteins and cause them to become "sticky". This process is called glycosylation and is a major factor in atherosclerosis and other diabetes complications. The extent of glycosolation is reflected in the blood level of glycosylated hemoglobin.
Diet is an important factor in the prevention and treatment of diabetes. Current dietary recommendations promoted by the American Diabetes Association, the American Heart Association, the American Cancer Society, and the US Department of Agriculture call for a diet containing 55% carbohydrate (in % of energy) with an emphasis on starch-containing foods, 15% protein, and 30% fat (10% monounsaturated, 10% polyunsaturated and 10% saturated fat).
Researchers at the Veterans Affairs Medical Center and the University of Minnesota now report that a high
protein diet (40% carbohydrate, 30% protein and 30% fat) is superior to the recommended high
carbohydrate diet in keeping glucose levels under control. Their clinical trial of the two diets involved 12
patients (10 men and 2 women) with mild, untreated diabetes. The study participants consumed the two
diets for 5 weeks separated by a 2-5 week washout period. The daily distribution of calorie intake was 21%
for breakfast, 27% for lunch, 13% for an afternoon snack, 34% for dinner, and 5% for a snack at 9 p.m. At
the end of the 5-week test period the researchers observed a significant reduction in glucose levels with the
high protein diet, particularly in the evening. They also noted a highly significant decrease in glycosylated
hemoglobin in both diets, but it was substantially more pronounced after the protein diet than after the
standard diabetes diet (0.8% versus 0.3%). Mean fasting triglyceride concentrations were significantly lower
in the protein diet group and decreased by 20% over the 5-week period. There were no significant
differences in cholesterol levels nor were any changes in weight or blood pressure observed in the two
groups. The researchers conclude that adhering to a high protein diet (protein=30% of energy intake)
improves glucose control in patients with mild, untreated diabetes.