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.
See the scientific wording
A 30-gram plant-based protein drink consumed at breakfast produces acute increases in plasma GLP-1 and PYY concentrations and suppresses subjective appetite to a similar extent as a 30-gram animal-based protein breakfast in healthy young and older adults, when energy and protein content are matched and despite differences in food form.
Very strong evidence
Randomized trialsOne good-quality study supports this claim.
What the research says
1 study reviewedSupporting (1)
Randomized Controlled TrialHuman2025
When people drank a plant-based protein shake or ate a solid animal-based protein meal with the same amount of protein, both made them feel just as full and raised the same fullness hormones in their blood. So, it doesn’t matter if the protein comes from plants or animals—what matters is how much protein you eat.
Contradicting (0)
No contradicting studies found yet
That doesn't mean it's settled — it just means no study has tested the opposite.
Quality-weighted scoring: we follow the GRADE framework — each study is rated High, Moderate, Low, or Very Low based on study design, methodology rigor, and risk of bias. A single high-quality RCT can outweigh several weaker observational studies.
Scores reflect study quality, not just count.
When protein is digested, its amino acids travel to the lower intestine and trigger special cells to release two hormones, GLP-1 and PYY. These hormones send signals to the brain through nerves and direct pathways, making a person feel full and reducing the desire to eat more. This happens the same way whether the protein comes from plants or animals, as long as the amount of protein and calories is the same.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting study
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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.
Mechanism
1 studyWhen you eat protein, your body breaks it into amino acids that reach your lower intestine and trigger the release of two hormones that tell your brain you're full. This happens the same way whether the protein comes from plants or animals, as long as the amount is the same.
When protein is digested, its amino acids travel to the lower intestine and trigger special cells to release two hormones, GLP-1 and PYY. These hormones send signals to the brain through nerves and direct pathways, making a person feel full and reducing the desire to eat more. This happens the same way whether the protein comes from plants or animals, as long as the amount of protein and calories is the same.
Dietary protein is broken down into amino acids during digestion and reaches the distal small intestine and colon.
Amino acids bind to G-protein-coupled receptors on enteroendocrine L-cells, activating intracellular calcium signaling.
Activated L-cells release stored vesicles of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) into the bloodstream.
Circulating GLP-1 and PYY bind to receptors on vagal afferent nerves and neurons in the arcuate nucleus of the hypothalamus.
Neural and hormonal signals from the gut reduce hunger perception and increase satiety, leading to decreased subjective appetite.
Evidence from Studies
Supporting (1)
Community contributions welcome
When people drank a plant-based protein shake or ate a solid animal-based protein meal with the same amount of protein, both made them feel just as full and raised the same fullness hormones in their blood. So, it doesn’t matter if the protein comes from plants or animals—what matters is how much protein you eat.
Contradicting (0)
Community contributions welcome
Score Breakdown
No multi-axis breakdown available yet. The overall Pro / Against score above is the best signal.
- No clinical evidence is available; the score reflects mechanistic plausibility only.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Systematic Review of Plant-Based vs. Animal-Based Protein Drinks on Satiety Hormones and Appetite in Healthy Adults
Population: Healthy young and older adults; Intervention: 30-gram plant-based protein drink at breakfast; Comparator: 30-gram animal-based protein breakfast; Outcome: Plasma GLP-1 and PYY concentrations and subjective appetite scores measured over 2–4 hours; Duration: Single-meal acute studies across multiple trials.
Double-Blind Crossover Trial Comparing 30g Plant-Based vs. Animal-Based Protein Drinks on Satiety Hormones in Healthy Adults
Population: Healthy young and older adults; Intervention: 30g plant-based protein drink; Comparator: 30g animal-based protein drink; Outcome: Plasma GLP-1 and PYY concentrations and visual analog scale appetite scores at 0, 60, 120, 180 minutes; Duration: Single-meal crossover design with washout period; Control: Randomized, double-blind, matched for energy, protein, and macronutrients.
Prospective Cohort Study of Daily Plant-Based vs. Animal-Based Protein Intake and Satiety Hormone Patterns in Healthy Adults
Population: Healthy young and older adults; Intervention: Habitual consumption of plant-based or animal-based protein breakfasts; Comparator: Group assignment by dietary pattern; Outcome: Repeated measurements of plasma GLP-1, PYY, and appetite over weeks; Duration: 4–12 weeks; Control: Adjusted for age, sex, BMI, and total energy intake.
Cross-Sectional Analysis of Protein Source and Postprandial Satiety Hormone Levels in Healthy Adults
Population: Healthy young and older adults; Intervention: Single breakfast meal of plant-based or animal-based protein; Comparator: Grouped by protein source consumed; Outcome: Single-time-point measurement of plasma GLP-1, PYY, and appetite scores; Duration: Single day; Control: Adjusted for age, sex, BMI, and fasting state.
In Vitro Analysis of Plant-Based vs. Animal-Based Protein Hydrolysates on Enteroendocrine Cell Secretion of GLP-1 and PYY
Population: Human enteroendocrine cell lines (e.g., STC-1); Intervention: Exposure to hydrolysates of plant-based protein (e.g., pea) and animal-based protein (e.g., whey); Comparator: Control media; Outcome: Quantification of GLP-1 and PYY secretion over 1–4 hours; Duration: Acute exposure; Control: Matched amino acid profiles and concentrations.