Whey protein ingestion has been shown to reduce feelings of hunger and promote satiety making it a valuable aid in weight loss programs. Whey protein during weight loss has also been shown to preserve lean body mass.

One of the best strategies for utilizing whey protein is taking it before or between meals. Studies have shown that consumption of whey protein in small amounts prior to a meal, improves after-meal blood sugar control. A new study by researchers from the University of Toronto has better defined the mechanism underlying this beneficial effect.

Background Data:

Whey protein has been shown to prevent after-meal elevations in blood sugar more effectively than a similar amount of other protein sources. This effect is due in part to whey protein increasing insulin secretion by the pancreas. However, whey protein also contains bioactive peptides that increase the release of gut hormones such as cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) that play a role in gastric emptying, appetite control, and blood sugar regulation.

Other benefits of whey protein:

  • Whey protein has the highest biological value of any protein.
  • Whey protein is a rich source of branched chain amino acids (BCAAs) that are metabolized directly into muscle tissue and are the first ones used during periods of exercise.
  • Whey protein is an excellent source of the essential amino acid, leucine. Research has shown that individuals who exercise benefit from diets high in leucine and have more lean muscle tissue and less body fat compared to individuals whose diet contains lower levels of leucine. Whey protein isolate has approximately 50% more leucine than soy protein isolate.
  • Whey protein is a soluble, easy to digest protein and is efficiently absorbed into the body.

New Data:

To more fully identify the mechanism of action of whey protein on reducing after-meal glucose levels, healthy young men received on separate occasions whey protein (10 and 20 g), glucose (10 and 20 g) or water (control). Acetaminophen (1.5 g) was added to each pre-meal intake preloads to measure gastric emptying.

Plasma concentrations of acetaminophen, glucose, and β-cell and gastrointestinal hormones were measured before pre-meals (baseline) and at intervals before (0-30 min) and after (50-230 min) a preset pizza meal (12 kcal/kg). Whey protein slowed pre-meal gastric emptying rate compared to the control and 10 g glucose and induced lower pre-meal insulin and C-peptide than the glucose pre-meals. Glucose, but not whey protein, increased pre-meal blood sugar levels. Compared with glucose, whey protein resulted in higher post-meal levels of GLP-1 and peptide tyrosine-tyrosine (PYY) and lower insulin concentrations, without altering insulin secretion and extraction rates.

In conclusion, whey protein resulted in lower mean plasma glucose, insulin and C-peptide, but higher GLP-1 and PYY concentrations than the glucose pre-meals. These effects indicate that whey protein lowers after-meal blood sugar levels by both insulin-dependent and insulin-independent mechanisms.


While whey protein is effective on its own, even better results occur when it is combined with the revolutionary dietary fiber matrix PGX. Like whey protein, PGX has been shown to produce a significant increase in GLP-1. Studies with a synthetic, injectable form of GLP-1 produces significant weight loss in humans as it makes most people feel full, leading to reduced food intake. PGX appears to produce the same effect naturally. PGX not only leads to pulses of GLP-1 release into the bloodstream, as it passes throughout the entire digestive tract it has also been shown to increase the number of the cells that produce GLP-1 – the L cells – within the intestinal tract. This mechanism explains the prolonged effect of PGX on feelings of satiety.


Akhavan T, Luhovyy BL, Panahi S, et al. Mechanism of action of pre-meal consumption of whey protein on glycemic control in young adults. J Nutr Biochem. 2014 Jan;25(1):36-43.

Dr. Michael Murray

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