App, smart scale and weight loss: an analysis of 665 users

A study published in JMIR Formative Research (2023) looked back at the data of 665 users with obesity (BMI of 30 or more) of an intermittent fasting app; 244 of them also used a scale that estimates body fat and muscle percentage. Users were grouped by how much they used the app.

Results: app use and weight

Smart scale users used the app significantly more consistently. Active users lost significantly more weight than less active ones. In the body composition analysis, app use might be related to fat loss and an increase in muscle mass: the authors put it as a possibility.

The authors find a possible association between the app's game and nudging elements (interactive tools, goals, challenges, progress tracking) and more consistent use, and conclude that they need further study.

What the study says and does not say

It is a retrospective analysis of data collected by the app, not a trial, and the authors declare that they are all Kilo Health employees.

They write that users' age, physical activity and diet were not recorded and might explain part of the changes. To establish an effect, they conclude, a prospective study with a control group would be needed: what exists today is an association.

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.