The Claim

In healthy, normal-weight adults, a 25% caloric restriction sustained over 24 months causes a 13% reduction in body weight and a greater-than-expected decline in sleeping energy expenditure, indicating metabolic adaptation that persists beyond changes attributable to loss of fat mass, muscle mass, or total body weight.

Source: Effect of caloric restriction on organ size and its contribution to metabolic adaptation: an ancillary analysis of CALERIE 2

What the research says

Supports is higher

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

Supports
69score
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

When healthy, normal-weight people eat 25% fewer calories for two years, they lose weight—but their bodies also burn even fewer calories at rest than you’d expect just from losing weight, as if their metabolism slows down on its own.

See the scientific wording

In healthy, normal-weight adults, a 25% caloric restriction over 24 months leads to a 13% reduction in body weight and a greater-than-expected decline in sleeping energy expenditure, suggesting metabolic adaptation that persists beyond what can be explained by loss of fat mass, muscle mass, or body weight alone.

Why this might work

When food intake drops by 25% for two years, the body shrinks its most energy-hungry organs—like the liver, brain, kidneys, and heart—and also loses some muscle. These organs normally burn a lot of calories just to stay alive. When they get smaller, they use less energy, so the body burns fewer calories at rest than expected, even after accounting for how much weight was lost.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Effect of caloric restriction on organ size and its contribution to metabolic adaptation: an ancillary analysis of CALERIE 2

    When healthy people ate 25% less food for two years, they lost 13% of their weight—but their bodies also burned even fewer calories at rest than expected, as if their metabolism slowed down on its own, even after accounting for the weight they lost.

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

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