Popular diet books have long recommended limiting particular types of macronutrients — usually carbohydrate or fat — to bring about weight loss and improve overall health. Some have additionally encouraged an increased intake of protein, the third type of macronutrient in the human diet, for the same reasons. While not all popular diet books address diabetes, many suggest that their recommendations can help with blood glucose control as well as weight loss.
At the same time, respected health organizations such as the American Diabetes Association (ADA) and the Joslin Diabetes Center have also published dietary guidelines for people with diabetes or prediabetes. (In prediabetes, blood glucose levels are higher than normal but not high enough for a diagnosis of diabetes. Having prediabetes raises the risk of developing Type 2 diabetes.) Both recommend weight loss for people who are overweight and give suggestions for losing weight.
Diet and weight loss are relevant topics for people with diabetes, since what you eat affects blood glucose control — not to mention blood pressure and blood lipid (cholesterol and triglyceride) levels — and losing excess weight can improve diabetes control and overall health. But with all the different books and guidelines out there, it can be difficult for the average person to know which eating plan might really have the desired effects while minimizing undesired effects such as feelings of chronic hunger.
In the interest of determining whether there are any truths to the claims that restricting or increasing the proportion of a particular macronutrient in the diet is beneficial, researchers have in recent years been testing various diets. Among the questions asked by researchers are whether following a particular diet leads to weight loss, a change in the proportion of body fat to muscle, improved cholesterol levels, lower triglyceride levels, lower blood glucose levels, and lower insulin resistance (which should lead to better blood glucose control).
This article examines some of the research that’s been done on diets with varying macronutrient composition. It also reviews the current nutrition recommendations of the ADA for all people with diabetes and those of the Joslin Diabetes Center for overweight people with either Type 2 diabetes or prediabetes.
According to the ADA, medical nutrition therapy (more commonly referred to as “meal planning”) for diabetes should aim to achieve and maintain the following:
- Blood glucose levels in the normal range or as close to normal as is safely possible
- Cholesterol and triglyceride levels that reduce the risk for vascular (blood vessel) disease
- Blood pressure levels in the normal range or as close to normal as is safely possible
In addition, a person’s meal plan should be designed to prevent or slow the rate of development of chronic complications of diabetes, address individual nutrition needs, and maintain the pleasure in eating.
While the ADA does not recommend specific proportions of carbohydrate, fat, and protein in the diet, it does recommend the following for preventing Type 2 diabetes in adults who are at high risk of developing it:
- Reducing calorie intake