Diabetes Self-Management Blog

Controlling after-meal blood sugar levels is a continuing battle for many people with diabetes. Now, a small new study from Israel indicates that eating whey protein prior to a meal improves the body’s insulin response and helps control glucose levels after the meal.

Along with casein, whey is one of the two main proteins found in milk. Eating protein is known to stimulate the production of glucagon-like peptide-1 (GLP-1), a hormone that triggers the production of insulin.

To determine whether consuming whey protein before a meal would improve blood glucose control after the meal, researchers recruited 15 people with well-controlled Type 2 diabetes who were taking only metformin or a sulfonylurea drug. The participants were randomly assigned to receive either 50 grams of whey protein in 250 milliliters of water or a placebo (inactive treatment — in this case, 250 milliliters of water) followed, 30 minutes later, by a standard high-glycemic-index breakfast composed of three slices of white bread and sugar-containing jelly. (The glycemic index measures how much a food affects blood glucose levels.) Blood samples were taken at 30 minutes prior to the meal, when the meal was served, and at 15, 30, 60, 90, 120, 150, and 180 minutes after the meal.

Two weeks after their initial study visit, the participants were assigned to repeat the trial using the alternate treatment (either the whey protein or the placebo). Because of this crossover design, the study was statistically powerful in spite of the small number of subjects.

The researchers found that, over the course of the entire 180-minute after-meal period, blood glucose levels were 28% lower in those who had received whey protein compared to those who had received placebo. Levels of insulin and c-peptide (a by-product of insulin creation) were higher by 105% and 43%, respectively, in the whey-protein group. The insulin response within the first 30 minutes after breakfast was also 96% higher in people who had consumed whey protein — an important finding, since loss of the early insulin response is a significant contributor to after-meal glucose spikes. Levels of GLP-1 were additionally 141% higher in people who had consumed whey protein.

“In summary, consumption of whey protein shortly before a high-glycemic-index breakfast increased the early and late post-meal insulin secretin, improved GLP-1 responses, and reduced post-meal blood sugar levels in Type 2 diabetic patients,” the study authors note. They add that whey protein is inexpensive and easy to use and that any brand of whey protein concentrate without added sugar or other nutrients would be suitable.

Based on the results of this study, the researchers are considering conducting a trial to evaluate whether the beneficial effects of whey protein on blood glucose, insulin, and GLP-1 are long lasting.

For more information, read the article “Consuming whey protein before meals could help improve blood glucose control in people with diabetes” or see the study’s abstract in the journal Diabetologia. To find out more about whey protein, see this piece by certified diabetes educator and registered dietitian Amy Campbell. And to learn more about other foods that may help with blood sugar control, read these articles.


  1. Interesting…

    Posted by Terri |
  2. I eat about 50 G protein powder in a low carb pancake each morning. Does anyone know if this reduces glucose spikes too, or do I need to take the powder in the form used in the study?

    Posted by Catherine L. |
  3. I am lactose intolerant and my dietician recommended whey protein. I noticed the high amount of lactose in the whey protein. I bought one with the lowest amount of lactose(2%). I got very sick, diarrhea, bloating, burping, it was awful.

    A frienf recommended a protein with hemp instead in it. I don’t know much about hemp. Would that be an OK subsitute. I have heard that it tastes awful.

    Do you have any other recommendations. I am a diabetic, Type II, on Januvia working on loosing weight.

    Posted by Carol Wong |
  4. Hi Ms. Wong,

    Thank you for your question. For more information on controlling after-meal blood glucose spikes, please see the article “Strike the Spike II,” by certified diabetes educator Gary Scheiner.

    Diane Fennell
    Web Editor

    Posted by Diane Fennell |
  5. For those watching their caloric intake, 50g of most whey powders contain around 200 calories, about 25% of which come from fat.

    Posted by Joe |
  6. What diabetic eats three pieces of bread with jam for breakfast? Perhaps a breakfast containing two eggs and perhaps adding a protein side dish might be better for keeping blood sugar lower. Just a thought.

    Posted by JohnC |
  7. Wht is whey protein?. Can be made at home from milk If so how?. This would help many who are experiencing to obtain from Market the whey protein. I am diabetic but under good control

    Posted by G V Rao |
  8. Hi Ms Wong

    You may want to look at the product called Isopure Protein, zero carb and lactose free.


    Posted by Doug |

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