The Claim

During 60 hours of fasting in healthy humans, insulin suppresses proteolysis, reducing muscle amino acid release by approximately 40%, without increasing protein synthesis.

Source: Effect of starvation on human muscle protein metabolism and its response to insulin.

What the research says

Supports is higher

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

Supports
26score
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.

How it works
1 study reviewed
In plain English

In healthy humans undergoing a 60-hour fast, insulin decreases the release of amino acids from muscle by 40% by reducing the breakdown of muscle protein, and does not increase the rate of muscle protein formation.

See the scientific wording

During 60 hours of fasting in healthy humans, insulin reduces muscle amino acid release by suppressing proteolysis (amino acid appearance) by approximately 40%, without stimulating protein synthesis (disposal).

Why this might work

When insulin is present during fasting, it binds to muscle cells and turns off the system that breaks down muscle proteins. This stops the release of amino acids into the blood, without making the body build more protein.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Effect of starvation on human muscle protein metabolism and its response to insulin.

    During a 60-hour fast, muscles release more amino acids because they’re breaking down more protein. The study found that giving insulin cuts this breakdown by about 40%, without making muscles build more protein — just like the claim says.

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.