Impact of sleep, screen time, depression, and stress on weight change in the intensive weight loss phase of the LIFE study

BACKGROUND: The LIFE study is a two-phase randomized clinical trial comparing two approaches to maintaining weight loss following guided weight loss. Phase I provided a nonrandomized intensive 6-month behavioral weight loss intervention to 472 obese (BMI 30–50) adult participants. Phase II is the randomized weight-loss maintenance portion of the study. This paper focuses on Phase I measures of sleep, screen time, depression, and stress. METHODS: The Phase I intervention consisted of 22 group sessions led over 26 weeks by behavioral counselors. Recommendations included reducing dietary intake by 500 calories per day, adopting the DASH dietary pattern, and increasing physical exercise to at least 180 minutes per week. Measures reported here are sleep time, insomnia, screen time, depression, and stress at entry and post weight loss intervention follow up. RESULTS: The mean weight loss for all participants over the intensive Phase I weight loss intervention was 6.3 kg (SD 7.1). Sixty percent (N=285) of participants lost at least 4.5 kg (10 lbs) and were randomized into Phase II. Participants (N=472) attended a mean of 73.1 % (SD 26.7) of sessions, completed 5.1 (SD 1.9) daily food records/week, and reported 195.1 (SD 123.1) minutes of exercise per week. Using logistic regression, sleep time (quadratic trend, p=.030) and lower stress (p=.024) at entry predicted success in the weight loss program, and lower baseline stress predicted greater weight loss during Phase I (p=.021). In addition, weight loss was significantly correlated with declines in stress (p=.048) and depression (p=.035). CONCLUSION: Results suggest that clinicians and investigators might consider targeting sleep, depression, and stress as part of a behavioral weight loss intervention.