lack of sleep is so common that the standard reply to ‘How
are you?’ is: ‘Shattered!’ But a growing body of
evidence indicates that chronic tiredness isn’t just affecting
our ability to function well – it’s also making us fat.
Around 60 per
cent of British adults are overweight or obese, and research suggests
that the cause may not be overeating or lack of exercise, but sleep
As you will
see, the reason that singer Jennifer Lopez looks ten years younger
than she is may be due to her ability to get eight hours of sleep
done a series of studies looking at weight and sleep, and studying
the metabolic rate,’ says Dr Shahrad Taheri, a consultant endocrinologist
at Birmingham Heartlands Hospital.
that people who sleep for significantly less than seven hours a
night often end up being obese.’
It also seems
that people who sleep for fewer than four hours a night are 73 percent
more likely to gain excess weight, while restricting sleep can lead
to cravings for up to 900 extra calories a day.
This much food
on top of a normal diet could result in an alarming weight gain
of up to 2lb a week.
suggested that although participants had no significant weight problems
beforehand, their weight grew as their sleeping time shrank.
of sleep seems to stimulate the hormones that regulate appetite,’
explains Dr Taheri. ‘It leads to higher levels of ghrelin,
a hormone that triggers appetite, and lower levels of leptin, that
tells your body it’s full.’
And the problem
is set to increase. In the past 50 years, the average night’s
sleep has dropped from nine to seven hours.
And a new survey
by the Vitality Show reveals that just 19 per cent of adults enjoy
a full eight hours a night, while 16 percent are getting by on fewer
Over half of
us are regularly so weary at work that we long to go home, while
59 per cent of women in their 30s are ‘tired all the time’.
Britain, this is Broken Night Britain – and while the occasional
late bedtime can be slept off, our chronic levels of sleep deprivation
are pushing us beyond mere tiredness into ill-health, with an increased
risk of diabetes and heart disease.
is plenty of evidence to support the idea that restricted sleep
leads to haywire hormones, Dr Taheri’s team is investigating
other factors in the connection between insomnia and weight gain.
you’re awake, the more time there is to eat, for instance,’
he adds. ‘And obesity is likely to lead to broken sleep. Weight
is a factor in sleep apnoea [a sudden halt in breathing patterns]
and snoring, which are more likely to wake you during the night,
so you can end up in a vicious cycle.’
have found that lack of sleep can double the risk of obesity in
never been a good sleeper and have always struggled with my weight,’
says 32-year-old Claudia Phillips, from Surrey.
20s, I started being unable to sleep for more than an hour at a
‘My GP thought
the stress of my job may have been a factor and he prescribed sleeping
pills. But he also believed the insomnia and weight gain could be
linked as, without sleep, the body does not metabolise food effectively.’
also meant Claudia would raid the fridge – ‘The logic being
that a full tummy might help me nod off,’ she says. ‘My
weight crept up to 14st, which is a lot for someone who’s 5ft
In an informal
experiment by a U.S. magazine, led by Dr Michael Breus, a group
of women were asked to keep their eating and exercise habits as
they were, but to sleep for seven-and-a-half hours a night.
all the women lost between 3lb and 15lb. Now, a larger U.S. study
is investigating the effect that sleeping for longer has on body
weight. ‘We are looking at the prevention of obesity,’
Dr Taheri says. ‘The connection [between sleep deprivation
and putting on weight] holds true everywhere, even Japan.’
Dr Taheri recommends
between seven and eight hours of uninterrupted sleep a night.