edited by katie barnes. email:
katiebarnes@leisuremedia.com research round-up
New research shows that dieters can improve their chances of losing fat by getting a good night’s sleep. We fi nd out more
dream diet S
leep health is no new phenomenon – a good night of catching the z’s has been shown to improve our fitness
performance (see HCM Nov/Dec 08, p59), help us look more beautiful, and alleviate symptoms associated with lack of sleep such as bad mood and impaired cognitive function. And now a study by the University of Chicago* – published last October in the Annals of Internal Medicine – has found that adequate sleep cannot only help those on a diet to increase their fat loss, but can also help to suppress feelings of hunger.
the study The small study was based on 10 slightly overweight, non-smoking people – three were women, seven were men. Their ages ranged from 35 to 49 and their BMI ranged from 25, which is considered to be just overweight, up to 32, which is considered to be obese. Each participant was put on a diet,
where calories were restricted to 90 per cent of what they each required to maintain their weight without exercise. This daily calorie allowance was maintained throughout the study. Participants were then observed over
two 14-day periods. During these periods, they spent the nights in a laboratory. For the fi rst fortnight, 8.5 hours was allocated to sleep and in the second two weeks
Sleep to lose weight: A poor night’s sleep reduced fat loss by 55 per cent
only 5.5 hours was set aside for sleep. During the day they carried on with their typical home/work life routine.
the results During the first, longer sleep study, participants slept for an average of seven hours and 25 minutes a night. In the short-sleep programme, participants got around five hours 14 minutes’ sleep a night – more than two hours fewer than they had in the first phase. The dieters in the study lost the same
amount of weight – 6.6lbs on average – during each two-week session, whether they got a full night’s sleep or whether their sleep was limited. So there was no difference in the amount of weight lost. However, those who got more sleep
did lose more fat: they lost 3.1lbs of actual fat and 3.3lbs of fat-free body mass (such as protein). In comparison, those who had less sleep only lost 1.3lbs of fat but 5.3lbs of fat-free body mass. Those who got less sleep also felt hungrier, it was found. When the
amount of sleep was reduced, the dieters produced more ghrelin – a hormone that stimulates hunger and food intake and that reduces energy expenditure. Dr Plamen Penev, the study director
and assistant professor of medicine at the University of Chicago, says: “If your goal is to lose fat, skipping sleep is like poking a stick in your bicycle wheels. Cutting back on sleep, a behaviour that is ubiquitous in modern society, appears to compromise efforts to lose fat through dieting. In our study, it reduced fat loss by 55 per cent.” He adds: “For the fi rst time, we
have evidence that the amount of sleep makes a big difference to the results of dietary interventions. People should not ignore the way they sleep when going on a diet. Obtaining adequate sleep may enhance the benefi cial effects of a diet. Not getting enough sleep could defeat the desired effects.” It was acknowledged that the study was limited due to its small sample size.
* Penev, Palmen D et al. Insufficient Sleep Undermines Dietary Efforts to Reduce Adiposity. Annals of Internal Medicine (2010) february 2011 © cybertrek 2011 Read Health Club Management online
healthclubmanagement.co.uk/digital 77
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