Evaluating the effects of different diets on blood sugar control in patients with T2DM

This review assessed the effects of various diets for achieving blood sugar control, improving cholesterol levels and losing weight in patients with type 2 diabetes mellitus (T2DM). 

Patients with T2DM have high blood sugar levels mainly due to insulin resistance (the body fails to respond to insulin actions). Insulin is needed for the body to use glucose as energy. T2DM is considered a lifestyle disease. Despite having a number of drugs to help control this condition, a lifestyle change by adopting a healthy diet is considered key in T2DM management. There have been developed a great number of diets that can help T2DM patients reduce blood sugar levels. The Mediterranean diet involves foods that are full of unrefined cereals, vegetables, olive oils, fruits, fish and moderate consumption of dairy products. Another well-known diet is the low-glycemic index (GI) diet. The GI is a measure of how quickly blood sugar levels rise after eating a particular type of food. Low GI foods slowly raise blood sugar levels after meals. Low-carbohydrate diets limit the consumption of carbohydrates (sugars) and promote protein and fat consumption. These diets have a different influence on weight loss, blood cholesterol and sugar levels and there is no consensus of an ideal diet to help T2DM patients control their blood sugar levels and maintain a healthy body weight. 

This review evaluated 20 studies involving a total of 3073 T2DM patients. All studies evaluated the effects of certain diets on blood sugar control, cholesterol levels and weight loss in patients with T2DM. The evaluated diets were low-carbohydrate diet, Mediterranean diets, low-GI, low-fat, high-fiber and high protein diets. Blood sugar control was measured through the glycated hemoglobin (HbA1c), a test that gives an average of blood sugar levels from the last 2 to 3 months.

Studies that evaluated low-carbohydrate diets recorded a decrease in HbA1c levels by 0.14% compared to patients under low-GI diet who had a decrease in HbA1c levels by 0.12%. Also, Mediterranean diets were associated with a 0.47% decrease, while high protein diet indicated a 0.28% decrease in HbA1c levels. The 0.47% decrease in HbA1c for the Mediterranean diet was similar to that achieved through anti-diabetes medication. Moreover, the Mediterranean diet led to a greater weight loss compared to other diets. All diets except for the high protein diet were effective in increasing the ‘good-cholesterol’, with no significant difference in reducing ‘bad-cholesterol’ levels.

In summary, this review showed that various diets can be used to effectively reduce blood sugar levels and promote weight loss, as well as improving cholesterol levels in patients with T2DM.

Talk to your doctor to see what diet best fits your situation.