The Claim

An 8-day very low-calorie diet (600 kcal/day) in morbidly obese adults (BMI ≥40 kg/m²) undergoing bariatric surgery is associated with a 5% reduction in body weight, of which 85% is attributable to fat mass loss, with significant reductions in neck, waist, and hip circumferences.

Source: Very low-calorie diet in candidates for bariatric surgery: change in body composition during rapid weight loss

What the research says

Supports is higher

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

Supports
34score
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 morbidly obese adults preparing for bariatric surgery, an 8-day diet of 600 calories per day results in a 5% loss of body weight, with 85% of that loss coming from fat mass, along with measurable decreases in neck, waist, and hip measurements.

See the scientific wording

An 8-day very low-calorie diet (600 kcal/day) in morbidly obese adults (BMI ≥40 kg/m²) undergoing bariatric surgery is associated with a 5% reduction in body weight, of which 85% is attributable to fat mass loss, with significant reductions in neck, waist, and hip circumferences, suggesting rapid preferential fat loss during short-term preoperative dietary intervention.

Why this might work

When calorie intake drops drastically, the body first uses up stored sugar in the liver and muscles. Once that sugar is gone, the body switches to breaking down fat for energy, pulling it out of fat tissue and burning it for fuel. This causes fat to shrink quickly in areas like the waist, neck, and hips, while muscle stays mostly unchanged.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Very low-calorie diet in candidates for bariatric surgery: change in body composition during rapid weight loss

    In severely obese people preparing for surgery, eating only 600 calories a day for 8 days caused them to lose 5% of their body weight — and most of that (85%) was fat, not muscle. Their waist, neck, and hips also got smaller, just like the claim said.

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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