Protein, Blood Sugar and Diabetes: Evidence on Protein, Whey and Amino Acids

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If you have diabetes, especially if you use insulin or other glucose-lowering medicines, ask your diabetes team before adding protein powder, whey or amino acid products. Protein can affect blood sugar after meals: the American Diabetes Association (ADA) 2025 Standards of Care say consumption of fat and protein can affect early and delayed postprandial glycemia (blood sugar after eating), and advise a cautious approach to raising insulin doses for high-fat or high-protein mixed meals. [1] This page is information only and does not replace your care plan. Never stop or change a prescribed medicine on your own.

How to read the evidence on this page

We label findings "guideline statement", "mixed", "limited" (few or small trials), "observational" (people were watched, not assigned, so cause is unproven) and "Proper evidence not found". A change in blood sugar after one meal or a lab marker is not the same as better long-term health.

What the ADA says about how much protein

The ADA 2025 Standards say there is no evidence that moving daily protein above or below the amount recommended for the general public, typically 0.8 to 1.5 g per kg of body weight per day or 15 to 20 percent of calories, will improve health, and that research is inconclusive on the ideal amount for blood sugar or heart risk. [1] Protein goals should be individualized based on current eating patterns. [1] The ADA also says some research has found successful management of type 2 diabetes with slightly higher protein (20 to 30 percent of calories), which may help fullness. [1] An earlier ADA consensus report noted limited research on protein amounts in people with diabetes or prediabetes without kidney disease. [2]

The ADA advises people with diabetes, and those at risk, to include more plant-based protein sources such as nuts, seeds and legumes within a diverse eating pattern, to reduce cardiovascular risk. [1] NIDDK's plate method puts protein foods such as lean meats, fish, dairy or tofu on one quarter of the plate. [3]

For diabetes with kidney disease, see Protein and Kidney Disease, which notes the KDOQI ranges differ.

Whey and milk protein: trials

These were study amounts used under trial conditions, not advice. The 2023 analysis was in adults generally, not only people with diabetes. [5]

Amino acids and diabetes

• Blood levels versus supplements: Prospective studies found higher blood levels of branched-chain amino acids (BCAAs), aromatic amino acids, phospholipids and triglycerides were associated with the later onset of prediabetes and type 2 diabetes. [7] Other work linked higher glycine and glutamine levels to lower risk. [8] These are markers in the blood in observational studies; they do not show that taking BCAA, glycine or glutamine supplements raises or lowers risk.
• Taurine: a 2022 meta-analysis of 5 trials (209 people with diabetes) reported lower HbA1c with taurine; the sample is small. [9] See Taurine.
• BCAA, EAA and other amino acid products: Proper evidence not found that they improve diabetes outcomes. We searched PubMed for amino acid supplementation and glycemic control in type 2 diabetes and found no meta-analysis we could use. See BCAAs and Arginine and Citrulline.
• Other blood sugar supplements: see Chromium and Berberine.

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