Type 2 diabetes is characterized by insulin resistance and chronically elevated blood sugar levels. Weight loss is often part of the primary treatment of type 2 diabetes; however, some weight loss diets may have more insulin-sensitizing effects than others. Findings of one report show that a high protein weight loss diet can reverse prediabetes by increasing insulin-sensitizing hormones.

Digestion of carbohydrates begins when sweetness receptors in the mouth are activated, leading to the release of insulin and hormones that augment insulin metabolism, such as incretins. In type 2 diabetes, incretins such as glucagon-like peptide (GLP)-1 and glucose-dependent insulinotropic peptide (GIP) are reduced, contributing to insulin resistance and increasing abdominal obesity. Pharmaceutical treatments for type 2 diabetes include GLP-1 activators, which can be effective at reducing blood sugar levels and increasing feelings of satiety after eating. High protein diets (30 percent of calories) have also been shown to enhance incretin signaling, making them an important strategy for treating prediabetes.

The authors recruited 24 participants who had obesity and prediabetes and randomly assigned them to either a high-carb diet (55 percent carbohydrate, 30 percent fat, 15 percent protein) or a high-protein diet (30 percent protein, 30 percent fat, 40 percent carbohydrate) for six months. The diets were designed to produce a 500 calorie per day deficit so that participants would lose weight. Participants completed an oral glucose tolerance test, during which they consumed 75 grams of glucose (equivalent to the amount of sugar in two 12 ounce cans of soda). The researchers measured blood glucose, insulin, GLP-1, and GIP levels during the test.

After six months, 100 percent of participants consuming the high-protein diet had remission of their prediabetes, while only 30 percent of participants consuming the high-carb diet experienced remission. Participants in both groups experienced weight loss (about 10 percent of their body weight) and improved insulin sensitivity; however, the participants consuming the high-protein diet had higher levels of GLP-1 and GIP and larger reductions in insulin resistance. Importantly, participants consuming the high-protein diet had increased lean muscle mass, while participants in the high-carb protein lost muscle mass.

These results demonstrate that high protein diets may be an effective strategy for improving insulin sensitivity and reducing type 2 diabetes risk. Learn more about high-protein diets and how to implement them in our new interview with Dr. Stuart Phillips.

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