A good night’s sleep is one of the keys to good health—and may also be a key to maintaining a healthy weight. There is mounting evidence that people who get too little sleep have a higher risk of weight gain and obesity than people who get seven to eight hours of sleep a night. Given our society’s increasing tendency to burn the midnight oil—in 1998, 35 percent of American adults were getting 8 hours of sleep a night, and by 2005 that had dropped to 26 percent—lack of sleep could be a major contributor to the obesity epidemic...

Most studies that measure adults’ sleep habits at one point in time (cross-sectional studies) have found a link between short sleep duration and obesity. Longitudinal studies, though, can better answer questions about causality—and in adults the findings from such studies have been less consistent than those in children.

The number of Britons getting just five to six hours sleep a night has risen dramatically in the past three years, with 40% not getting the NHS recommended six to nine hours.

A third of the population (33%) now get by on five to six hours sleep a night compared to 27% in 2010. And the majority of people (70%) sleep for seven hours or less.

Eight of 25 putative risk factors were associated with a risk of obesity in the final models: parental obesity (both parents: adjusted odds ratio, 10.44, 95% confidence interval 5.11 to 21.32), very early (by 43 months) body mass index or adiposity rebound (15.00, 5.32 to 42.30), more than eight hours spent watching television per week at age 3 years (1.55, 1.13 to 2.12), catch-up growth (2.60, 1.09 to 6.16), standard deviation score for weight at age 8 months (3.13, 1.43 to 6.85) and 18 months (2.65, 1.25 to 5.59); weight gain in first year (1.06, 1.02 to 1.10 per 100 g increase); birth weight, per 100 g (1.05, 1.03 to 1.07); and short (< 10.5 hours) sleep duration at age 3 years (1.45, 1.10 to 1.89).

Short sleep duration can affect both energy intake and energy expenditure. It results in tiredness that may hamper physical activity, and alters metabolic hormones to increase appetite and affect food selection. Additionally, extra time awake provides increased opportunity for food intake. Other potential mechanisms include effects of sleep on basal metabolic rate, thermic effect of food and non‐exercise activity thermogenesis.

The findings of new research presented at ENDO 2015, the annual meeting of the Endocrine Society in San Diego, CA, suggest that losing just half an hour of sleep can have long-term consequences for body weight and metabolism.

For the study, researchers from Weill Cornell Medical College in Doha, Qatar, recruited 522 patients who had been recently diagnosed with type 2 diabetes.

At the start of the study, the participants' height, weight and waist circumference were measured and samples of their blood were analyzed for insulin sensitivity.

The participants were required to keep sleep diaries, from which their weekday "sleep debt" was calculated.

The participants at the start of the study who had weekday sleep debt were found to be 72% more likely to be obese, compared with participants who had no weekday sleep debt. By follow-up at 6 months, the association between weekday sleep debt and obesity and insulin resistance was found to be significant.

At 12-month follow-up, the researchers calculated that for every 30 minutes of weekday sleep debt there was an associated 17% increased risk of obesity and 39% increased risk of insulin resistance.

Sleep is essential for good health, but for many people, work is a major factor that stands in the way, given the longstanding tradition of shift work and the trend of employees being accessible 24/7 via smart phones and tablets. The workplace, both in terms of psycho­logical demands (or work load) and the physical environment, seems to play a significant contributing role to sleep loss, which subsequently has a dele­terious effect on weight management. That’s because missing out on both the quantity and quality of sleep sets in motion biological and behavioural processes that lead to increased food intake, fat storage and physical inactivity.