Of 100 enrolled subjects, 82 completed all 3 visits and data presented is from these subjects. Baseline characteristics of completers and non-completers were compared and no differences between the groups were found. Additionally, no gender differences were found and analysis was performed on the entire group. Descriptive characteristics of the study sample are presented in tables and .
Baseline clinical/demographic characteristics of study completers (N = 82).
Subject characteristics at the baseline visit (i.e. before Thanksgiving) for all study completers (N = 82).
The distribution of weight changes between pre-Thanksgiving and post-New Year's for all subjects are shown in Figure . In the 31 subjects that gained weight, 12 of the subjects (15%) gained 2.0 kg or more over the course of the holiday season, 32 (39%) subjects actually lost body weight, and 19 (23%) were deemed weight stable (i.e. a change of ± 0.5 kg) from pre-Thanksgiving to post-New Year's. Thus, on average, body weight did not significantly increase from pre-Thanksgiving (71.3 ± 14 kg) to post-New Year's (71.2 ± 15 kg; P = 0.71).
Distribution of change in weight of subjects completing the study pre-Thanksgiving to post-New Year (N = 82).
Figure depicts the relationships between the changes in body weight in relation to the change in percent fat, fat mass, fat free mass, and trunk fat mass. Positive significant relationships (P < 0.001) were found between changes in body weight and percent fat, total fat mass, total fat free mass, and trunk fat mass (panels A, B, C, and D). In those subjects judged to be weight-stable, 17 (89%) increased fat mass and 3 (16%) had an increased fat-free mass. Similar significant relationships (P < 0.001) were found between changes in BMI and percent fat, total fat mass, total fat free mass, and trunk fat mass (Figure panels A, B, C, and D).
Figure 2 Relationship between change in body weight and percent fat, total fat mass, total fat free mass, and trunk fat mass (N = 82). The middle solid line represents the mean change of the x-axis variable and the upper and lower dashed line represents +2 standard (more ...)
Figure 3 Relationship between the change in BMI and percent fat, total fat mass, total fat free mass, and trunk fat mass (N = 82). The middle solid line represents the mean change of the x-axis variable and the upper and lower dashed line represents +2 standard (more ...)
On average, a significant (P < 0.01) increase in percent body fat and total fat mass was observed between pre-Thanksgiving and post New Year's visits, while total fat-free mass remained unchanged (Table ).
Body weight and body distribution changes for all subjects (N = 82).
In an attempt to gain a clearer picture of the impact of the holiday season on fat deposition, regional depots (i.e. arm, leg, and trunk) fat mass and fat free mass were investigated. Significant (P < 0.01) increases in trunk and leg fat mass were observed between the pre-Thanksgiving and post New-Year's visits, with a significant (P < 0.01) decrease observed in both leg and arm fat free mass (Table ). No significant change in trunk fat free mass or arm fat mass was observed (Table ).
To more clearly delineate the relationship between holiday weight gain and body weight status, subjects were divided into one of two groups, either normal body weight, defined as a BMI < 24.9 kg/m2 (N = 54) or overweight/obese, defined as BMI ≥ 25 kg/m2 (N = 28) (Table ). The normal weight group lost a significant amount of body weight between the pre-Thanksgiving and post New Year's visits (P < 0.05) and had the largest number of individuals (9) who lost weight 2.0 kg or more, while the overweight/obese group had a greater number of subjects (8), who had gained more than 2.0 kg of body weight, although, on average, this was not significant (P = 0.14) Table .
Body weight and body distribution changes by BMI classification.
Both the normal and overweight/obese groups gained a significant amount of body fat (P < 0.05) between the pre-Thanksgiving and New Year's visits (Table ). A significant decrease in total fat-free mass in the normal weight group (P < 0.05) was observed, though the trend was the same for the overweight/obese group but it did not reach significance (P = 0.06) (Table ). A summary of regional (i.e. arms, leg, and trunk) body composition for both the normal and overweight/obese groups are presented in Table . The general trend observed in both groups was for a significant increase in leg and trunk fat and a decrease in arm and leg fat free mass (Table ).