Blog · Diet and body composition

Body fat and metabolic risk: a trial protocol

Protocol of a randomised trial in 114 students: for the authors, body fat percentage says more about risk than BMI. It has no results yet.

Updated October 20, 2026

The protocol of a randomised controlled trial, published in BMJ Open in 2023 and available on PMC, starts from a point the authors take from earlier studies: body composition and body fat percentage can predict health risks better than classifying obesity by BMI alone, especially in the overweight and obese range.

The limit of many studies

The authors note that most studies focus on body weight and weight loss rather than on maintaining a balanced body composition.

Two people with the same weight can have very different body compositions, and different risk profiles.

A couple in an elegant hotel bar in the evening: he smiles while she shows him the Digital Twin figure on her phone.

Ai-generated illustration

Body fat and BMI: where they part ways

The gap between BMI and risk shows mostly in the overweight and obese range, where people with the same BMI can have very different body compositions.

Someone with a lot of muscle and little visceral fat, such as an athlete, can have a high BMI and a low risk.

A person with little muscle and a lot of abdominal fat can have a moderate BMI and a higher risk. Telling these cases apart takes a body composition measurement. The authors also recall that body composition is associated with a higher risk of chronic metabolic and cardiovascular disease.

A habit is read in months, not in one meal.

What the study will measure

The article is a protocol: it describes a trial in 114 inactive university students aged 18 to 25, with a 16-week physical activity programme delivered in person and online. The main outcome is body composition (muscle mass, fat mass, BMI, body fat percentage). This article does not contain results yet.

The Digital Twin and this research

The Digital Twin lines up the data your devices write to your phone, such as weight, body fat percentage and lean mass when your scale records them, and shows you how they change over time. It does not calculate risk indices and it does not diagnose: this research describes groups of people, not you. These are data to read together with your doctor.

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