Effects of a high-protein and low-fat diet vs a low-protein and high-fat diet on blood glucose, serum lipoproteins, and cholesterol metabolism in noninsulin-dependent diabetics.

Six middle-aged patients with noninsulin-dependent diabetes and six normoglycemic control subjects were fed protein-rich and fat-poor (diet A) or protein-poor and fat-rich food (diet B). The patients were hyperglycemic, VLDL triglycerides levels were higher, and HDL cholesterol levels lower than corresponding findings in control subjects. Bile acid formation and biliary lipid composition did not differ between the two groups, but net steroid balance in the patients was elevated by a factor of approximately 2. A switch from diet A to diet B in control subjects was associated with an increase in HDL cholesterol and decreases in bile acid synthesis and net steroid balance. Lipoprotein pattern in the patients remained unchanged, and effects on total bile acid production and steroid balance were less consistent. It is suggested that the response in the patients reflected diabetes-associated abnormalities in lipid metabolism.