Research

Hormonal

Whey protein induces greater satiety and reduces subsequent food intake compared to casein due to faster gastric emptying, leading to higher postprandial plasma amino acid, CCK, and GLP-1 concentrations.

If you want to feel fuller and eat less at your next meal, choose whey protein over casein. Whey digests faster, causing a quicker spike in satiety hormones (CCK and GLP-1) and blood amino acids. This 'fast' protein effect can help you naturally reduce your calorie intake at subsequent meals compared to 'slow' proteins like casein.

GoodSupportsHIGH confidence
These results implicate post-absorptive increases in plasma amino acids together with both CCK and GLP-1 as potential mediators of the increased satiety response to whey...
Wendy L. Hall et al. · British Journal Of Nutrition · 2003

Why this rating

Randomized, single-blind, within-subject design with objective biochemical measures and ad libitum food intake, though limited to healthy, lean volunteers.

Source

Casein and whey exert different effects on plasma amino acid profiles, gastrointestinal hormone secretion and appetite

Wendy L. Hall et al. · British Journal Of Nutrition · 2003

DOI 10.1079/bjn2002760

crossover · n=25Cited 729×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →