A common question is: “How are amino acids related to peptides and proteins”?

Simple answer: amino acids are like train cars, peptides are short trains, and proteins are long trains.

So, is the nutritive value of a protein (train) greater than the sum of its amino acid (train car) parts?

The short answer is yes, but the following study shows that this may not always be the case.

Researchers compared the weight loss effects an amino acid mixture simulating whey protein to whey protein,

Here is the upshot of the study (my emphasis; satiety is a measure of “feeling full”):

“There were no significant differences (P=0·24) in the ad libitum test meal intakes between the WPI (268·5 (sem 27·3) g) and the AAM (238·4 (sem 22·7) g) preload meals. Subjective VAS ratings of appetite did not differ significantly between the WPI and the AAM preload meals (P>0·05). Intact whey protein and a free AAM simulating the whey protein showed similar effects on satiety. This suggests that the satiating effect of whey protein may be related to its specific amino acid composition.”

In short, the groups didn’t (statistically) respond differently to the amino acid mixture compared to the whey protein.

Food for thought…

Here is the link to the full study