In middle-to-older adults, eating a low-protein breakfast with 0.13 grams of whey or pea protein per kilogram of body weight temporarily lowers the hunger hormone ghrelin and raises the satiety...

Pro

Against

Mechanism

Synthesis from 1 study

How it works

After eating protein, amino acids signal the gut to release hormones that reduce hunger signals and increase fullness signals. These signals appear quickly but do not change how hungry or full older adults feel because their brain does not respond to these gut signals the same way as younger people.

Most probable mechanism

In Simple Terms

When protein is digested, amino acids enter the bloodstream and signal the gut to release hormones that turn off hunger signals and turn on fullness signals. This happens quickly after eating, but the feeling of hunger or fullness does not change because the brain does not respond to these signals in older adults.

Causal chain

Whey protein is rapidly broken down in the small intestine, releasing a higher concentration of free amino acids, especially leucine, into the bloodstream compared to pea protein.

Verified by multiple studies

which leads to

Elevated plasma amino acids, particularly leucine, stimulate L-cells in the distal small intestine and colon to secrete glucagon-like peptide-1 (GLP-1).

Supported by evidence

which leads to

Amino acid sensing by enteroendocrine cells activates G-protein-coupled receptors that trigger intracellular calcium signaling and vesicular release of GLP-1.

Supported by evidence

which leads to

Increased GLP-1 and amino acid levels inhibit ghrelin secretion from gastric X/A-like cells through vagal afferent and direct endocrine signaling.

Supported by evidence

which leads to

The transient rise in GLP-1 and fall in ghrelin do not alter perceived hunger, fullness, or composite appetite scores because central appetite regulation in middle-to-older aged adults is resistant to these peripheral hormonal signals.

Supported by evidence

Evidence from Studies

Supporting (1)

Community contributions welcome

Postprandial plasma amino acid and appetite responses to a low protein breakfast supplemented with whey or pea protein in middle-to-older aged adults

Randomized Controlled Trial

Human

2025 Feb 11

Contradicting (0)

Community contributions welcome

No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Source Study

Postprandial plasma amino acid and appetite responses to a low protein breakfast supplemented with whey or pea protein in middle-to-older aged adults

Score: 64

DOI: 10.1007/s00394-025-03605-0

Similar Assertions

In middle-to-older aged adults, adding 0.13 grams of whey or pea protein per kilogram of body weight to a low-protein breakfast results in the same short-term reduction in hunger and increase in fullness over three hours, with no difference in blood levels of ghrelin or GLP-1 or in overall appetite ratings between the two protein types.

94%

When middle-to-older adults eat a low-protein breakfast and add either whey or pea protein powder at 0.13 grams per kilogram of body weight, both types of protein raise essential amino acids and appetite hormones by the same amount, and neither affects hunger or fullness more than the other.

84%

When healthy young and older adults consume a 30-gram protein drink made from plants or animals at breakfast, the resulting changes in satiety hormones and feelings of fullness are the same, even though one is a liquid and the other is a solid food.

80%

In middle-to-older adults, eating a low-protein breakfast with 0.13 grams of whey or pea protein per kilogram of body weight does not change blood sugar or insulin levels compared to before eating.

80%

Among overweight or obese adolescent girls who skip breakfast, eating a morning meal with 35 grams of protein from eggs and beef reduces hunger, increases fullness, alters hunger-related hormones, and reduces evening snacking on high-fat foods compared to skipping breakfast or eating a low-protein cereal breakfast, without changing total daily calorie intake.

79%