The average adult watches almost 5 hours of television (TV) per day, an amount associated with increased risks for obesity. This trial examines the effects of TV reduction on energy intake (EI), energy expenditure (EE), energy balance, body mass index (BMI), (calculated as weight in kilograms divided by height in meters squared), and sleep in overweight and obese adults.
Randomized controlled trial of 36 adults with a BMI of 25 to 50 who self-reported a minimum of 3 h/d of TV viewing. Participants were enrolled in home-based protocols from January through July 2008. After a 3-week observation phase, participants were stratified by BMI and randomized to an observation-only control group (n = 16) or an intervention group (n = 20) for 3 additional weeks. The intervention consisted of reducing TV viewing by 50% of each participant's objectively measured baseline enforced by an electronic lock-out system.
Although not statistically significant, both groups reduced their EI (−125 kcal/d [95% CI, −303 to 52] vs −38 [95% CI, −265 to 190]) (P = .52) for intervention and control group participants, respectively, where CI indicates confidence interval. The intervention group significantly increased EE (119 kcal/d [95% CI, 23 to 215]) compared with controls (−95 kcal/d [95% CI, −254 to 65]) (P = .02). Energy balance was negative in the intervention group between phases (−244 kcal/d [95% CI, −459 to −30]) but positive in controls (57 kcal/d [95% CI, −216 to 330]) (P = .07). The intervention group showed a greater reduction in BMI (−0.25 [95% CI, −0.45 to −0.05] vs −0.06 [95% CI, −0.43 to 0.31] in controls) (P = .33). There was no change in sleep.
Reducing TV viewing in our sample produced a statistically significant increase in EE but no apparent change in EI after 3 weeks of intervention.
clinicaltrials.gov Identifier: NCT00622050