The Claim

In healthy adults, protein preloads do not increase subjective satiety ratings compared to isocaloric carbohydrate preloads over a 5-day period.

Source: A randomized cross-over trial to determine the effect of a protein vs. carbohydrate preload on energy balance in ad libitum settings

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
88score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Description
1 study reviewed
In plain English

When healthy adults consume protein-based meals before eating, their feelings of fullness are not higher than when they consume the same number of calories from carbohydrates over five days.

See the scientific wording

In healthy adults, protein preloads do not increase subjective satiety ratings compared to isocaloric carbohydrate preloads over a 5-day period, despite theoretical mechanisms linking protein to appetite suppression, suggesting that acute satiety effects may not translate to measurable changes in ad libitum eating behavior.

Why this might work

When protein is eaten, the body uses more energy to digest it, which raises metabolism, but this extra energy use does not trigger the brain's hunger-control center to reduce appetite. Even though protein releases amino acids that should signal fullness, the brain does not respond with lower hunger ratings or reduced eating.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: A randomized cross-over trial to determine the effect of a protein vs. carbohydrate preload on energy balance in ad libitum settings

    People drank protein shakes before meals for five days and felt just as hungry as when they drank sugary shakes—even though their bodies burned a little more calories after protein. They ate the same amount either way, so protein didn’t make them feel fuller or eat less.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.