Assessing the effects of the holiday season on body weight, body fat percentage, and blood pressure

Background:
Longitudinal studies among U.S. adults show that average weight gain is 1kg per year. The purpose of this study was to assess the effects of the Holiday Season (Thanksgiving to New Years Day) on changes in body weight, body fat percentage (BF%), and blood pressure (BP) in adults.

Methods: A total of 148 subjects (age 18-65y) were evaluated in November (baseline) and January (follow-up). Data collected at each visit included height, weight, BF%, BP, and resting heart rate (HR). In both visits, subjects were evaluated at the same time of day wearing a hospital gown, were instructed to refrain from vigorous exercise for 12 hours, and fasted for 4 hours prior to testing. BF% was measured using bioelectrical impedance analysis. Statistical significance was set at p < 0.05.

Results: From baseline to follow up visits, there were significant increases in body weight (0.78±1.28kg), BF% (0.52±2.27%), systolic and diastolic BP (1.84±10.10mmHg and 2.32±14.20mmHg, respectively), and HR (2.32±11.52bpm). When analyzed by body mass index category, obese subjects showed a significantly greater increase in BF% from November to January compared to normal weight subjects (p < 0.02) and trended for a difference compared to overweight subjects (p= 0.09).

Conclusions: Adult subjects showed an average increase in body weight of 0.78kg between baseline and follow-up visits. If these subjects gain the national average of 1kg per year, up to 78% of annual weight gain could be attributed to the holiday season. Additionally, obese subjects may be most at risk as they showed the greatest increases in BF%.