Weighing daily can help shed pounds

In free-living, real-world settings, frequent self-weighing seems to help boost weight loss regardless of specific interventions, according to a recent study. Such an effect is more apparent in obese and overweight individuals.

“We found that daily self-weighing in particular was associated with weight loss, whereas breaks of 30 days or longer were associated with increased weight,” the researchers said. “However, although there was a dose-response relationship between self-weighing intensity and weight change, the correlation remained low, indicating that self-weighing explains only a small fraction of the variations in weight.”

Random sampling yielded a study cohort of 9,768 participants (mean age 41.5 years, 66.7 percent men) who had been using smart scales for at least 1 year. Longitudinal correlations between weighing frequency and weight change were evaluated and compared among normal weight (42.0 percent; n=4,003), overweight (38.4 percent; n=3,748), and obese (20.7 percent; n=2,017) subgroups.

In total, there were 4,230,928 weight measurements collected over the entire study period, and each participant used their smart device a median of 352 times. This corresponded to roughly 2.80 weight measurements per week. Overweight participants tended to weigh themselves most frequently; the variation between groups was slight but significant, ranging from 38.99 percent in obese participants to 40.86 percent in the overweight group (p=0.006). [J Med Internet Res 2021;23:e25529]

Over the mean follow-up duration of 1,085 days, there was an average weight loss of 0.59 kg, corresponding to a –0.37 percent weight change. This varied greatly across body mass index (BMI) subgroups: overweight and obese participants lost 0.58 and 3.35 kg, respectively, while those who were of normal weight at baseline gained 0.78 kg.

Frequency of self-weighing was significantly and inversely associated with weight change, though only weakly so (r, –0.111; p<0.001). Such an interaction was stronger for obese and overweight participants than those with normal BMI at baseline.

Breaks in self-weighing was common, and most (72.5 percent) of the participants stepped away from their smart devices for ≥30 days over the follow-up period. Overall, the median number of such breaks was 3, lasting an average duration of 58.83 days.

During these breaks, participants gained a mean of 0.85 kg on average, an effect that was significantly stronger in the obese and overweight vs normal weight groups (1.37 and 0.93 vs 0.58 kg; p<0.001). Spearman correlation analysis confirmed that the duration of self-weighing breaks was significantly associated with weight gain (p<0.001).

“This study extends the well-established relationship between frequent self-weighing and favourable weight loss outcomes beyond specific weight loss interventions,” the researchers said. “Daily self-weighing in particular was associated with weight loss.” Importantly, however, taking prolonged breaks from such self-weighing habits was highly prevalent in the study.

“The break in self-weighing was associated with increased weight, with a dose-response relationship with the length of the break: The longer the break, the more weight tended to increase. [O]ur results underscore the evidence that missing self-weighing data do not occur randomly and might be a sign of risk for weight gain,” they added.