Research

Hormonal

High-protein diets induce insulin resistance and impair glucose homeostasis by promoting gluconeogenesis and reducing peripheral insulin sensitivity, whereas fish protein (specifically cod) improves insulin sensitivity compared to other protein sources.

If you are consuming high amounts of protein, prioritize fish (like cod) over other sources like casein or beef to potentially improve insulin sensitivity. Be aware that very high protein intake, regardless of source, may impair glucose homeostasis in some individuals by increasing gluconeogenesis and insulin resistance.

GoodQualifiesHIGH confidence
consumption of a high-protein diet for six months in healthy nonobese individuals induced a higher glucose-stimulated insulin secretion, increased fasting glucose level, impaired suppression of hepatic glucose output by insulin, and enhanced gluconeogenesis... a one-year study in type 1 diabetic patients revealed that consumption of a high-protein diet decreased overall insulin sensitivity... cod protein–fed rats in comparison to casein-fed animals are protected against the development of insulin resistance and glucose intolerance
Frédéric Tremblay et al. · Annual Review of Nutrition · 2007

Why this rating

The paper is a review citing multiple human and animal studies, including clamp techniques, but notes some conflicting human data.

Source

Role of Dietary Proteins and Amino Acids in the Pathogenesis of Insulin Resistance

Frédéric Tremblay et al. · Annual Review of Nutrition · 2007

DOI 10.1146/annurev.nutr.25.050304.092545

narrative_reviewCited 321×
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DOI resolved against Crossref · corpus check 2026-06-10

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