The Claim

In men with overweight or obesity, a dietary intervention reducing protein intake to 0.9 g/kg/day while increasing carbohydrate intake significantly increases fasting plasma fibroblast growth factor 21 (FGF21) concentrations, and the magnitude of this increase is inversely correlated with the amount of weight lost.

Source: Dietary Protein Reduction During Isocaloric Conditions Reduces Body Weight in Men With Overweight or Obesity.

What the research says

Supports is higher

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

Supports
68score
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.

Cause and effect
1 study reviewed
In plain English

In men with overweight or obesity, eating less protein and more carbohydrates raises levels of the protein FGF21 in the blood, and the greater the rise in FGF21, the less weight is lost.

See the scientific wording

In men with overweight or obesity, reducing dietary protein intake to 0.9 g/kg/day while increasing carbohydrate intake significantly increases fasting plasma fibroblast growth factor 21 (FGF21) concentrations, and the magnitude of this increase is inversely correlated with the amount of weight lost.

Why this might work

When protein intake drops, the liver detects the change and releases more FGF21 hormone into the blood. This hormone tells fat tissue to burn more energy as heat, so the body uses stored fat for fuel even when eating the same number of calories. The more FGF21 rises, the more fat is lost.

Supported mechanismbased on 1 study

What the research says

1 study
  1. Study: Dietary Protein Reduction During Isocaloric Conditions Reduces Body Weight in Men With Overweight or Obesity.

    When men with extra weight ate less protein and more carbs without eating fewer calories, their body made more of a hormone called FGF21—and the more this hormone went up, the more weight they lost. So yes, the study confirms this link.

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

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