Smartphone app does not appear to help with weight loss, study finds

A free smartphone app for weight loss did not appear to be effective in primary care, according to a new study.

Researchers performed a randomized, controlled trial at 2 academic primary care clinics to examine the effects of introducing a free smartphone app for weight loss. Primary care patients who had a BMI of 25 kg/m² or more were randomly assigned to 6 months of usual care with (intervention group) or without (control group) help downloading the MyFitnessPal app. The study's primary outcome measure was weight loss at 6 months; secondary outcome measures were changes in systolic blood pressure and behaviors, frequency of app use, and patient satisfaction. The study results were published in a supplement to the Nov. 18 Annals of Internal Medicine.

Overall, 212 patients were included in the study, 105 in the intervention group and 107 in the control group. Most patients (72%) were women, with a mean age of 43.3 years and a mean BMI of 33.4 kg/m². Twenty-six percent of the intervention group and 21% of the control group were lost to follow-up or had withdrawn from the study at 3 months; at 6 months, these percentages were 32% and 19%, respectively. Weight change (mean between-group difference, −0.30 kg; 95% CI, −1.50 to 0.95 kg; P=0.63) and change in systolic blood pressure (mean between-group difference, −1.7 mm Hg; 95% CI, −7.1 to 3.8 mm Hg; P=0.55) were minimal between the 2 groups at 6 months. While patients in the intervention group were more likely to set a personal calorie goal, other self-reported behaviors showed no between-group differences. Satisfaction with the app was high, but logins after the first month of use decreased sharply (97% of the intervention group at month 1 vs. 34% at month 6). Most patients who stopped using the app said they did so because the app was too time-consuming or too tedious.

The researchers noted that the study had a fairly high attrition rate and that patients were followed for only 6 months, among other limitations. However, they concluded that introducing a weight loss app to overweight primary care patients did not lead to increased weight loss, although the app might be useful in patients who are ready to self-monitor their calories as a way of losing weight. “For now, readiness and adherence to self-monitoring must be addressed for such apps as [MyFitnessPal] to affect obesity and its costly, long-term consequences in primary care settings,” the researchers wrote.