BBC News
London, UK
24 May, 2006



A good night's sleep may not just leave you feeling refreshed - it may also help to you keep trim.
Researchers from Ohio's Case Western Reserve University, followed nearly 70,000 women for 16 years.

They found women who slept five or fewer hours a night were a third more likely to put on at least 33lbs (15kg) than sound sleepers during that time.

Details were presented to the American Thoracic Society International Conference in San Diego.

The study is by far the largest to track the effects of sleep habits on weight gain over a long period of time.

It also found that lighter sleepers were 15% more likely to become obese compared with women who slept for seven hours a night.

Obesity is defined as having a Body Mass Index (BMI) of 30 or more. BMI is calculated by dividing weight in kilograms by the square of height in metres.

Eating not key

The researchers found that their findings had nothing to do with light sleepers eating too much, or taking too little exercise.

On average, women who slept five hours or less per night weighed 5.4 pounds more at the beginning of the study than those sleeping seven hours, and gained an additional 1.6 pounds more over the next 10 years.

Lead researcher Dr Sanjay Patel said: "That may not sound like much, but it is an average amount - some women gained much more than that, and even a small difference in weight can increase a person's risk of health problems such as diabetes and hypertension (blood pressure)."

"Prior studies have shown that after just a few days of sleep restriction, the hormones that control appetite cause people to become hungrier, so we thought that women who slept less might eat more.

"But in fact they ate less. That suggests that appetite and diet are not accounting for the weight gain in women who sleep less."

Fidgeting

Dr Patel said sleeping less might alter the number of calories a person burns when at rest.

Alternatively, he said people who sleep less might also be less prone to involuntary activity such as fidgeting, which can help to burn off calories.

A study by the US National Institute of Mental Health, published in the journal Sleep in 2004, produced similar findings.

The researchers suggested the key might be that sleep deprivation alters the balance of hormones which control the rate at which we burn off calories.

Dr Ian Campbell, a GP in Nottingham and medical director of the charity Weight Concern, said it might be that people who sleep less are more tired, and therefore less active during the day.

There may also be a natural hormonal response to the stress of insufficient sleep leading to changes in metabolic rate or even eating behaviours.

"What is clear though is that so much of the way we live our lives affects our health," he said.

"If we want to keep the risk of weight gain at bay there's nothing to beat a healthy diet, an active lifestyle, and a good night's rest."

Dr Andrew Cummin, of the Sleep Laboratory at Charing Cross Hospital, said: "Many women would like to know the secret of eating more without gaining weight.

"Sadly, the authors have no explanation. But it does seem that if you want to lose weight getting plenty of sleep may help."



http://news.bbc.co.uk/1/hi/health/5008824.stm

Sleep is easily the biggest non-nutritional metabolic affecter.

Recently I've been practically gorging on food. Carbs have been quite low, but the calories are outrageous compared to normal intake. I'm on summer break, so I'm basically laying about relaxing, sleeping as much as I want most of the time.

Basically, I'm eating more, and laying around. I mean this is a BIG difference here. I used to eat far less and I always was busy.
Sounds like I should expect to gain, right? Wrong.

Weight was lower than it's ever been upon waking... 111. I haven't seen a weight that low in, oh, several months? Oh and the first time I saw it, I was severely restricting food. To see it again, without trying, eating nearly twice as much is hilarious to me.

Could it all be dehydration from eating less carbs and sleeping more? Perhaps. But I doubt it. I feel "bonier". My face looks slimmer. I do think a lot of this has to do with a reduced stress response... and I've reduced that by sleeping more, abstaining from caffeine, and keeping carbs low.

I believe a truly functional metabolism is dynamic; that is to say, the more you eat, the more it burns, thus very little if any positive energy balance exists even when eating a lot of food. It is very difficult for a naturally thin person to gain weight, that's how it should be... and when I do all these things (sleep, eat low carb, no caffeine, lower stress) that's how mine works too.
Calorie counting and restricting food will let you lose weight, but it isn't comfortable and it's very psychologically difficult to do. Our true goal should be to try to get our metabolism more like the naturally thin. There's more at work here than what and how much we eat.

What a shallow study, from our learned Dr Patel. There are no statisics studied re their carbo consumption. What if the lo carbos had slept more? So here is another shallow study...If I have a hi carb day, ie a curry and rice lunch, I will be up a kilo, even after 8 hours sleep.