The Claim

In obese women, a 15-day very low-calorie diet causes an average weight loss of 6 kg, primarily from fat-free mass, leading to a reduction in resting metabolic rate.

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.

How it works
1 study reviewed
In plain English

Obese women who follow a very low-calorie diet for 15 days lose an average of 6 kilograms, mostly from muscle and other non-fat tissues, and their resting metabolic rate decreases as a result.

See the scientific wording

In obese women, a 15-day very low-calorie diet results in an average weight loss of 6 kg, primarily from fat-free mass, which contributes to the observed reduction in resting metabolic rate.

Why this might work

When calorie intake drops sharply, the body converts less of a thyroid hormone into its active form, slowing down cellular energy use. At the same time, the body breaks down muscle and other lean tissues for energy. Together, these changes cause the body to burn fewer calories at rest.

Supported 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, they lost about 6 pounds, mostly from muscle and other lean tissues, and their bodies burned fewer calories at rest — exactly what 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.