The Claim

In obese women, a 15-day very low-calorie diet at 1337 kJ/day is associated with a 12.5% reduction in resting metabolic rate (from 1793 to 1569 kcal/day) and a decrease in serum triiodothyronine (T3) from 1.1 to 1.0 μg/L.

Source: Resting Metabolic Rate, Body Composition and Thyroid Hormones

What the research says

Supports is higher

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

Supports
31score
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.

Correlation
1 study reviewed
In plain English

In obese women, consuming a very low-calorie diet for 15 days results in a measurable drop in resting metabolic rate and a reduction in serum triiodothyronine levels.

See the scientific wording

In obese women, a 15-day very low-calorie diet (1337 kJ/day) is associated with a 12.5% reduction in resting metabolic rate (from 1793 to 1569 kcal/day) and a decrease in serum triiodothyronine (T3) from 1.1 to 1.0 μg/L, suggesting a link between acute caloric restriction and downregulation of metabolic and thyroid hormone activity.

Why this might work

When food intake drops sharply, the body reduces the conversion of a thyroid hormone into its active form, which slows down energy use in cells, causing the body to burn fewer calories at rest.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Resting Metabolic Rate, Body Composition and Thyroid Hormones

    When obese women ate very few calories for two weeks, their bodies burned fewer calories at rest and made less of a thyroid hormone that helps control metabolism. This helps explain why losing weight gets harder over time.

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.

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