Control of blood glucose in type 2 diabetes without weight loss by modification of diet composition

Abstract

Background: Over the past several years our research group has taken a systematic, comprehensive approach to determining the effects on body function (hormonal and non-hormonal) of varying the amounts and types of proteins, carbohydrates and fats in the diet. We have been particularly interested in the dietary management of type 2 diabetes. Our objective has been to develop a diet for people with type 2 diabetes that does not require weight loss, oral agents, or insulin, but that still controls the blood glucose concentration. Our overall goal is to enable the person with type 2 diabetes to control their blood glucose by adjustment in the composition rather than the amount of food in their diet.

Methods: This paper is a brief summary and review of our recent diet-related research, and the rationale used in the development of diets that potentially are useful in the treatment of diabetes.

Results: We determined that, of the carbohydrates present in the diet, absorbed glucose is largely responsible for the food-induced increase in blood glucose concentration. We also determined that dietary protein increases insulin secretion and lowers blood glucose. Fat does not significantly affect blood glucose, but can affect insulin secretion and modify the absorption of carbohydrates. Based on these data, we tested the efficacy of diets with various protein:carbohydrate:fat ratios for 5 weeks on blood glucose control in people with untreated type 2 diabetes. The results were compared to those obtained in the same subjects after 5 weeks on a control diet with a protein:carbohydrate:fat ratio of 15:55:30. A 30:40:30 ratio diet resulted in a moderate but significant decrease in 24-hour integrated glucose area and % total glycohemoglobin (%tGHb). A 30:20:50 ratio diet resulted in a 38% decrease in 24-hour glucose area, a reduction in fasting glucose to near normal and a decrease in %tGHb from 9.8% to 7.6%. The response to a 30:30:40 ratio diet was similar.

Conclusion: Altering the diet composition could be a patient-empowering method of improving the hyperglycemia of type 2 diabetes without weight loss or pharmacologic intervention.

Figure 1

Plasma glucose response in 6 males with untreated diabetes following ingestion of "American meals" (top, broken red line) and "low starch meals" (bottom, solid black line). Bars indicate 24-hour net glucose area response using the fasting glucose concentration as baseline.

Figure 2

Glucose (left panel) and insulin (right panel) response to 50 g protein, given in the form of very lean beef to 8 normal subjects (bottom, broken lines) and 7 subjects with type 2 diabetes (top, solid lines).

Figure 3

Plasma glucose response in 12 subjects with type 2 diabetes. The response to the control diet (15% protein) is shown in the top, dotted red line. The response to the test diet (30% protein) is shown in the bottom, solid black line).

Figure 4

Net 24-hour integrated glucose (left) and insulin area responses (right) to ingestion of a 15% protein (red bar) or 30% protein (black bar) diet in 12 subjects with type 2 diabetes.

Figure 5

% total glycohemoglobin response to a 15% protein diet, (top, broken red line) and a 30% protein diet (bottom, solid black line) in 12 people with type 2 diabetes.

Figure 6

Glucose (left panel) and insulin (right panel) responses to ingestion of 50 g fat alone, or 50 g fat + 50 g carbohydrate in normal young subjects.

Figure 7

Glucose (left panel) and insulin (right panel) responses to ingestion of 50 g fat alone, or 50 g fat + 50 g carbohydrate in subjects with type 2 diabetes.

Figure 8

Plasma glucose response before (top broken red line) and after 5 weeks on a LoBAG₂₀ diet (bottom solid black line) in 8 men with untreated type 2 diabetes. Net area (left set of bars), using the fasting glucose concentration as baseline and total area (right set of bars), using zero glucose as baseline, before (red bars) and after 5 weeks on the diet (black bars).

Figure 9

Serum insulin response before (top broken red line) and after 5 weeks on a LoBAG₂₀ diet (bottom solid black line) in 8 men with untreated type 2 diabetes. Net area (left set of bars), using the fasting insulin concentration as baseline and total area (right set of bars), using zero insulin as baseline, before (red bars) and after 5 weeks on the diet (black bars).

Figure 10

% total glycohemoglobin during the 5 weeks on the control diet (top, broken red line) and during the 5 weeks on the LoBAG₂₀ diet (bottom, solid black line).

Figure 11

Theoretical rate of change of % total glycohemoglobin following an instantaneous change in blood glucose concentration.