In all three countries, the participants’ weight rose within 10 days after Christmas Day, as compared with 10 days before Christmas Day (weight increases of 0.4% in the United States, P<0.001; 0.6% in Germany, P<0.001; and 0.5% in Japan, P=0.005).
Significant weight gain was also observed around other major holidays in each country: participants’ weight increased by 0.3% in Japan during Golden Week (P<0.001), 0.2% in Germany during the Easter holiday (P<0.001), and 0.2% in the United States during the Thanksgiving holiday (P<0.001). Overall, from the minimum annual weight (Figure 1FIGURE 1
Yearly Holiday Weight Gain.), weight increased by 0.7% (0.6 kg) in the participants from the United States and 1.0% (0.8 kg) in those from Germany during the Christmas–New Year holiday season and 0.7% (0.5 kg) in participants from Japan during Golden Week.