High blood sugar isn't an issue that's siloed to people with type 1 diabetes or type 2 diabetes. In fact, keeping an eye on your blood glucose levels can help stave off obesity and other metabolic conditions that are so rampant today.

Some might even say that the hallmark of a healthy diet is how well it helps you manage your blood glucose and prevents blood sugar spikes.

Among the macronutrients, dietary protein is the most well-known for helping to regulate blood sugar, both on its own and when combined with carbohydrates. But how exactly does this work, and which foods are the best protein sources?

In this article, we'll discuss the effect of protein on blood glucose, what protein does as it's being digested, and which types of protein you should incorporate into your meal planning.

The Impact Of Protein On Blood Sugar

Each of the macronutrients (carbohydrates, fat, and sugar) all have a unique impact on your blood sugar. While carbohydrates tend to raise blood sugar rapidly, protein and fat have a more subtle impact. 

Blood sugar, also known as blood glucose, is simply the amount of glucose that's in your blood at any given time. Glucose is the direct product of carbohydrate digestion, which is why carbs tend to increase blood glucose so fast. In fact, carbohydrates begin their breakdown process in your mouth, while dietary fat and protein have to wait until they get to the stomach before any dismantling occurs.

It's understood that protein can assist with blood sugar regulation, but why exactly is that?

There are a handful of reasons:

#1 Protein takes longer to digest than carbohydrates. 

As you just learned, carbs can begin their process of digestion in your mouth, whereas protein doesn't begin its breakdown process until it reaches your stomach. Once its bonds start to break down in your stomach, protein needs to be sent to your small intestine for further dismantling. 

Several enzymes are involved in the breakdown of protein, along with hydrochloric acid, in your stomach. All in all, protein is a very energy and time-consuming nutrient to digest.[1]

#2 Protein is broken down into amino acids, not glucose. 

While glucose from carbs directly increases blood sugar, amino acids must first go through a process known as gluconeogenesis (GNG) before they can be turned into glucose. Furthermore, not all amino acids will go through GNG, as amino acids play a wide range of roles in your body. 

Therefore, unlike carbohydrates, the digested protein you consume may be sent to different areas of your body to help repair, rebuild, and renew various tissues, enzymes, DNA, hormones, and so on.

#3 Gluconeogenesis (GNG) won't spike blood sugar

Although amino acids can be turned into glucose, the process of GNG is tightly regulated, even when excess amino acids are available. This means the likelihood of protein spiking your blood sugar is very low, as the GNG pathway isn't set up to produce large amounts of glucose from amino acids at once.[2]

#4 Protein coingestion with carbohydrates slows the digestive process

You've likely heard that when you consume carbs, adding protein to your meal can help to curb spikes in blood sugar. This is due to all of the factors mentioned above and the impact of coingestion. 

When you consume a meal containing both protein and carbohydrates, your digestive juices and enzymes must tackle both simultaneously. In effect, protein is diluting your glucose absorption because there is only so much that your digestive tract can do at one time. Therefore, instead of working on the carbs first and rapidly breaking them down into glucose, your digestive system has to manage both protein and carbs simultaneously. 

The result? Slower absorption of your meal and slower release of glucose into your bloodstream. 

Protein, Blood Sugar, and Diabetes

If you have diabetes, particularly with uncontrolled insulin, there is some caution around protein due to contrasting research. 

On the one hand, studies show that high-protein diets can produce better glycemic control than diets that contain an average amount of protein for people with type 2 diabetes. In one study, a high protein diet resulted in a 40% decrease in glucose response post-meal and lowered glycated hemoglobin (which is a marker for blood sugar levels over several months).[3]

However, other research suggests that protein may have a different response in diabetics compared to non-diabetics. One theory suggests that insulin deficiency may allow gluconeogenesis (GNG) to proceed beyond its normal limits, creating excessive amounts of glucose from protein.[4]

This would likely occur if your cells weren't getting enough fuel due to insufficient insulin action, which would stimulate glucose production regardless of how much fuel is actually in the blood.

This doesn't mean that you should avoid protein if you have diabetes. In fact, it's best practice always to get to know your body and its specific needs when determining your ideal macronutrient ratio. If anything, the contrasting research only highlights the importance of measuring your blood sugar after meals to assess how your body responds to the nutrients you're providing. 

Generally speaking, however, replacing carbohydrates with protein will likely produce more regulated blood glucose levels. 

High-Quality Vs. Low-Quality Protein

Not all protein is created equal, so how do you know which types of protein will be the best for blood sugar regulation?

First, the source of your protein will make a significant difference in how your body responds to it. While it is possible to get protein from plant sources like whole grains and legumes, the protein from plants will also be packaged with a fair amount of carbohydrates. For the most part, plants are made up primarily of carbs, with some protein and fat incorporated into the matrix. 

This means that even though you may be getting 24 grams of protein from a half cup of lentils, you'll also be getting about 65 grams of carbs.[5]

When you consume protein from animal sources like meat, eggs, and fish, on the other hand, the vast majority of the calories come directly from protein.  

Furthermore, animal protein is generally considered high quality because it has a higher PDCAAS score. The PDCAAS, which stands for protein digestibility corrected amino acid score, takes into account the exact amino acids in the protein, in addition to how well that food source is digested and absorbed. 

PDCAAS considers human requirements for amino acids, as our bodies need a particular ratio of each for optimal growth and maintenance. While one food may be "high protein," it could lack relevant amounts of specific amino acids, ultimately taking it down a notch on the PDCAAS scale.[6]

Examples of High-Quality Protein

  • Red meat like beef, lamb, and pork
  • White meat like chicken and turkey
  • Eggs (all kinds)
  • Seafood like fish, scallops, shrimp, and shellfish
  • Dairy — particularly full-fat Greek yogurt and cottage cheese (low-fat versions often add more carbs, and you miss out on the healthy fats naturally contained in these foods)


Incorporating high-protein foods into your diet is an excellent way to improve blood sugar while also providing your body with the building blocks it needs to function optimally.

Blood sugar regulation can help you feel more calm and more focused (no sugar highs) while also optimizing your metabolism for weight loss.

And, of course, as part of diabetes management, regulating your blood sugar can significantly impact your progression. With that being said, glucose monitoring is crucial as you're learning how your body responds to different macronutrient ratios.

Keep in mind that in addition to adding more protein to your meals, steering clear of high-carb foods like starchy root vegetables and grains is a good idea. While these foods may come from natural sources, they can still impact blood sugar if your insulin isn't working optimally.


  2. Nuttall, Frank Q., Angela Ngo, and Mary C. Gannon. "Regulation of hepatic glucose production and the role of gluconeogenesis in humans: is the rate of gluconeogenesis constant?." Diabetes/metabolism research and reviews 24.6 (2008): 438-458.
  3. Gannon, Mary C., et al. "An increase in dietary protein improves the blood glucose response in persons with type 2 diabetes." The American journal of clinical nutrition 78.4 (2003): 734-741.
  4. Franz, Marion J. "Protein: metabolism and effect on blood glucose levels." The diabetes educator 23.6 (1997): 643-651.
  6. Hoffman, Jay R., and Michael J. Falvo. "Protein–which is best?." Journal of sports science & medicine 3.3 (2004): 118.

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