Carbohydrates are digested into glucose, which in turn will stimulate the release of insulin. When protein is eaten, either before or during a meal rich in carbohydrates, insulin response will be reduced. Different types of protein, such as whey or soy protein, help prevent a rapid spike in insulin. A low-carbohydrate, high-protein diet effectively maintains insulin levels in the blood, as research published in “Diabetes” in 2004 found.
Carbohydrate, Protein and Insulin Response
Glucose enters the small intestine from the stomach, where it is absorbed into the bloodstream to stimulate the release of insulin. Insulin binds to cells in the body, which allows them to absorb, use and store glucose. As glucose is absorbed into cells, levels fall, which in turn stops insulin production. If you are able to slow down how quickly glucose enters the small intestine, you will be able to slow down insulin response. Protein stimulates the release of several hormones that slow down the stomach's release of its contents into the small intestine.
How Protein Affects Insulin Response
In a study published in “Diabetes Care” in 2009, subjects diagnosed with type-2 diabetes ate beef-flavored soup before a mashed potato meal on three separate days. On one day, 55 grams of whey protein were added to the soup. On another day, the same amount of whey protein was added to the mashed potato. On the final day, no whey protein was added to the meal. At the end of the study, insulin levels were much higher when no whey was added to the meal. Insulin response was reduced when subjects received whey in the soup or the potatoes. There was no difference in insulin response if the whey was eaten in the soup before or in the mashed potatoes during the main meal.
Different Types of Protein
In a study published in the “Journal of Clinical Endocrinology & Metabolism" in 2006, researchers compared the response of insulin to whey and soy protein. Men ate 50 grams of liquid soy or whey protein prior to a buffet meal. As a control, some men also ate 50 grams of glucose before the meal. Their blood was measured prior to the protein or glucose ingestion and then at different time periods for several hours after the meal. Those who ate only the glucose prior to the meal experienced the highest levels of insulin, while both the soy and whey protein groups had a lower insulin response. No major differences in insulin response occurred between the two types of protein.
Research published in “Diabetes” in 2004 had subjects diagnosed with type-2 diabetes eat a control diet for five weeks followed by a high-protein, low-carbohydrate diet for five weeks. The control diet was composed of 55 percent carbohydrate, 15 percent protein and 30 percent fat. The test diet was composed of 20 percent of carbohydrate, 30 percent protein and 50 percent fat. Despite having similar insulin levels at the beginning of the study, subjects who followed the high-protein diet had 40 percent lower levels of insulin at the end of the study compared to the control diet.