r/Fitness (The Fitness Wiki)@fitness-wikiweb

Ignorer les mesures de taux de masse grasse fournies par les balances ou dispositifs …

what it claims

Ignore body fat percentage measurements provided by bioelectrical impedance scales or portable devices, as they lack precision and are excessively sensitive to variations in body hydration.

mixed

This recommendation is based on solid scientific grounds: scales using bioelectrical impedance (BIA) are notoriously sensitive to fluctuations in body water.

noli's read

This recommendation is based on solid scientific grounds: scales using bioelectrical impedance (BIA) are notoriously sensitive to fluctuations in body water. A randomized crossover study published in 2023 in the journal MDPI shows, for example, that recent liquid intake instantly distorts fat mass estimation by altering the body's electrical conductivity. Furthermore, comparative observational studies, such as the one published in Frontiers in 2024, confirm that these consumer-grade tools show significant margins of error compared to reference laboratory methods. The devices' internal calculations are actually based on average equations derived from age and weight, which greatly limits their precision on an individual scale. Nevertheless, the suggestion to reject these devices entirely is somewhat excessive: while they lack absolute precision, they remain useful for observing general long-term trends, provided that measurements are taken under strictly identical hydration conditions.

the sources

Claimed by r/Fitness (The Fitness Wiki). Noli grades the claim, never the person.

Decoded by Noli · July 13, 2026 · the original post

What the graded evidence says

Evidence: B

Effect: ad libitum energy intake as a function of dietary energy density — lowering dietary energy density consistently reduces spontaneous calorie intake at matched food weight/fullness; body-fat change tracks the resulting energy balance
Measured on: general adults

Energy balance is the driver, but it's affected by many things (satiety, food quality, sleep, activity), so it's not about rigid calorie math. 'Fat-burning' or 'negative-calorie' foods are a myth.