Holiday weight gain: small indulgences, big effects?

By Ana Espino | Published on January 2, 2026 | 3 min read


Every year, holiday periods—particularly Christmas, New Year’s, Thanksgiving, or Golden Week—are associated with social gatherings, rest… and often dietary excess. Many adults report slight weight gain during these festive periods. Although this phenomenon is widely acknowledged anecdotally, it has rarely been quantified rigorously.

Yet even modest weight gain, if repeated annually, could represent a silent but powerful mechanism of progressive weight increase, contributing to the rising prevalence of overweight and obesity in the general population.  

Previously available data suffered from major methodological limitations: infrequent measurements, self-reported weights, or small, non-representative samples. In this context, the present study was initiated to objectively and continuously measure the effect of holidays on body weight at an international scale. It is based on the analysis of data from connected scales used daily by participants in three countries with different food cultures—the United States, Germany, and Japan—over a full year.

How much weight do people really gain during the holidays?

In this study, 2,924 adults were selected and equipped with Withings smart scales over a 12-month period (2012–2013). Weight was measured daily, then aggregated and normalized. The researchers focused on weight changes around major holidays: Christmas and New Year’s, Thanksgiving, Easter, and Golden Week in Japan.

The results show a clear and rapid weight gain in the days following the holidays. In the United States, participants gained an average of 0.4% of their body weight immediately after Christmas. In Germany, the increase was even greater, reaching 0.6%, while in Japan, Golden Week led to a 0.5% increase. Other festive periods, such as Thanksgiving and Easter, were also associated with smaller gains, around 0.2%.

What is particularly striking is that nearly half of this weight gain persisted for several months after the holidays, with no spontaneous return to baseline weight. Even though the gain may seem small—between 0.5 and 1 kg on average—it could, when accumulated year after year, become a silent but meaningful contributor to chronic weight gain at the population level.

Small deviations that accumulate… slowly but surely

End-of-year holidays are associated with a moderate but significant weight gain, observed across multiple countries. This often-overlooked phenomenon likely contributes to gradual increases in body weight when it recurs annually. This study, based on daily data from connected scales, allows for precise and objective quantification of these seasonal weight variations.

However, several limitations remain and justify further research. Participants using connected devices are likely more health-conscious than the general population, which may lead to an underestimation of the true effect. The lack of information on lifestyle factors (diet, physical activity, sleep) limits interpretation of the underlying mechanisms.

Future studies should include more diverse populations, integrate behavioral and socioeconomic variables, and evaluate targeted prevention strategies to limit weight gain during festive periods.

Read next: Who is afraid of Christmas? Do holidays trigger psychiatric crises?