The Claim

In healthy, normal-weight adults undergoing 25% caloric restriction for 24 months, sleeping energy expenditure decreases by approximately 159 kcal/day at 12 months and 137 kcal/day at 24 months, exceeding predictions based on body mass, fat mass, and fat-free mass, indicating the presence of metabolic adaptation that persists beyond expected changes in tissue mass.

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.

Quantitative
1 study reviewed
In plain English

When healthy, normal-weight adults reduce their calorie intake by 25% for two years, their energy use during sleep drops by about 159 kcal per day after one year and 137 kcal per day after two years, more than can be explained by changes in body weight or composition.

See the scientific wording

In healthy, normal-weight adults undergoing 25% caloric restriction for 24 months, sleeping energy expenditure decreases by approximately 159 kcal/day at 12 months and 137 kcal/day at 24 months, exceeding predictions based on body mass, fat mass, and fat-free mass, suggesting the presence of metabolic adaptation that persists beyond expected changes in tissue mass.

Why this might work

When food intake drops sharply, the body shrinks its most energy-hungry organs — like the liver, brain, kidneys, and heart — and reduces muscle mass. These organs normally burn a lot of energy just to stay alive. When they get smaller, they use less energy, so the body burns fewer calories at rest, even after weight loss stops. This drop in energy use is bigger than what you'd expect just from losing weight, and it lasts for at least two years.

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 people ate 25% fewer calories for two years, their bodies burned more calories at rest than expected just from losing weight — meaning their metabolism slowed down on its own, even after they stopped losing weight.

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

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