Reference: BMJ 2018 Dec 10;363:k4867 (level 1 [likely reliable] evidence)
Obesity is a growing global epidemic, with worldwide obesity almost tripling since 1975 according to the World Health Organization (WHO). A reported 1.9 billion adults were overweight or obese in 2016, with over 650 million of those adults being obese. (World Health Organization.2018 Feb) A 2008 systematic review showed that there were very few trials on prevention of weight gain (only 10 publications across 5 databases as of 2008), all with vastly differing study design, intensity of intervention and varying levels of success. (Public Health Nutr. 2009 Nov) In Western cultures, the average weight gain from November to January is 0.5 kg, reported to be the main contributor to annual weight gain.(Physiol Behav. 2014 Jul) This holiday weight is often not lost during the spring and summer months, a phenomenon reflected in the rising rates of obesity. (N Engl J Med. 2000 Mar 23) Can discussing diet and weight management with patients around the holidays help prevent this holiday weight gain?
The Winter Weight Watch Study randomized 272 adults (mean age 43.9 years, 74 % white, 78 % women) with body mass index ≥ 20 kg/m2 (Public Health Nutr. 2009 Nov) to receive either a brief behavioral intervention to prevent weight gain or a pamphlet about healthy lifestyle choices (control) during the Christmas season (November and December). The mean baseline weights were 80.3 kg (177 lbs) in the intervention group and 79.7 kg (175.7) in the control group. Behavioral interventions included regular self-weighing (at least twice weekly), reflecting on one’s weight trajectory, education on weight management strategies, and information about the amount and type of physical activity required to expend the calories from common holiday season foods, with the overall goal of weight gain ≤ 0.5 kg (1.1 lbs). The primary outcome measured was weight at follow-up compared to baseline. 98% of participants had follow-up at 4 and 8 weeks and were included in analysis. Secondary outcomes included weight gain of 0.5 kg or less, frequency of self-weighing, body fat percentage, cognitive restraint of eating, emotional eating, and uncontrolled eating. Cognitive restraint of eating and the amount of both emotional and uncontrolled eating were measured using a questionnaire.
The mean weight change in the brief behavioral intervention group was -0.13 kg (-0.29 lbs) and +0.37 kg (+0.82 lbs) in the control group (adjusted p = 0.008). The brief behavioral intervention group also showed a significant increase in cognitive restraint of eating and drinking (adjusted p = 0.03), as well as an increase in self-weighing (p < 0.001) compared to the control group (p = 0.03). There were no significant differences between groups in weight gain < 0.5 kg (1.1 lbs) (occurring in 63.64% of participants in the brief behavioral intervention group vs. 58.96% in the control group), mean change in percent body fat (+0.14% in the brief behavioral intervention group vs. +0.15% in the control group), or emotional and uncontrolled eating.
The Winter Weight Watch Study showed that a brief behavioral intervention, involving weight monitoring, education on weight management, and information on physical activity to calorie equivalents for typical holiday foods, prevented weight gain over the Christmas period. However, the study group consisted of predominantly white women, and this limits the applicability of these results to a more diverse patient population. There have been no previous trials on brief interventions (< 10 weeks) to compare to, but one of the strengths of the study is the ease of replicability of the intervention. As the Christmas holiday season is a common time for weight gain in adults, placing a greater emphasis on discussing ways to prevent weight gain may be one way we can fight the rising rates of obesity.
For more information, see the topic Diets for Weight Loss in DynaMed.
This Resident Focus was written by Audrey Nguyen who attended the University of Virginia School of Medicine and is a third year Family Medicine resident at the University of Virginia. Her interests include inpatient acute care, nutrition and weight loss counselling, as well as working with under-served populations, including refugees and Native Americans. She likes to work out and try new foods in her spare time!