Obese adults who lose at least 5 per cent of their body weight sleep better and longer after six months of shedding flab, according to a new study.

   “This study confirms several studies reporting that weight loss is associated with increased sleep duration,” said the study’s lead investigator, Nasreen Alfaris from University of Pennsylvania, Philadelphia.

   The study found that weight loss at 6 months improved sleep quality, as well as mood, regardless of how the individuals lost the weight.

   The 2-year study compared three behavioural interventions for weight loss in obese adults treated in primary care practices.

   The 390 study subjects (311 women and 79 men) were randomly assigned to one of three programmes that provided varying amounts of support to achieve the same diet and exercise goals.

   Researchers evaluated changes in weight, sleep duration and quality, and mood after 6 and 24 months of treatment.

   They compared subjects who lost 5 per cent or more of their original body weight with those who lost less than 5 per cent, regardless of their group assignment.

   At month 6, subjects in both lifestyle counselling groups lost more weight on average than those in the usual care group, Alfaris said.

   Examining all three groups together, subjects who lost at least 5 per cent of their weight at month 6 reported that they gained an average of 21.6 minutes of sleep a night, compared with only 1.2 minutes for those who lost less than 5 per cent.

   Likewise, subjects who lost more than 5 per cent of initial weight reported greater improvements on measures of sleep quality and mood.

   The research was presented at the joint meeting of the International Society of Endocrinology and the Endocrine Society in Chicago.