Lose poundzzz with an afternoon nap

TAKE a nap in the afternoon if you want to lose weight.

That's the advice to be concluded from a study that found people burn 10 per cent more calories resting after lunch than when sleeping during the night.

Scientists say the discovery could also explain how the effects of the body clock clashing with late shift and night work can make people awake at later times more likely to put on weight.

The results also have implications for people who snack all day but stay up late surfing the internet. Research fellow Dr Kirsi-Marja Zitting, from Harvard University's medical school in the US said: “The fact that doing the same thing at one time of day burned so many more calories than doing the same thing at a different time of day surprised us.

“There is now emerging evidence that an irregular sleep-wake and fasting-feeding cycle, common in people working night or rotating shifts, can lead to disrupted circadian (24-hour body rhythm) timing, which in turn may alter energy balance and lead to increased obesity risk.”

Sleeping time is a key component in how we burn off calories. Between 60 to 70 per cent of all the calories we burn each day go while we are asleep to support basic functions such as breathing, circulation and temperature regulation.

The researchers, whose results were published in the journal Current Biology, put seven people in isolation in a sleeping lab with no clues as to time of day. They had assigned times to go to bed and wake up.

Each night those times were put back by four hours – the equivalent of travelling west across four time zones every day for three weeks.

Study co-author Associate Professor Jeanne Duffy explained: “Because they were doing the equivalent of circling the globe every week, their body's internal clock could not keep up and so it oscillated at its own pace. This allowed us to measure metabolic rate at all different biological times of day.”

The data showed that resting energy expenditure is lowest late at night but highest in the afternoon.

Professor Duffy added: “It is not only what we eat but when we eat and rest that impacts how much energy we burn or store as fat.

“Regularity of habits is important to overall health.”

The research team said that future studies will look at how appetite and the body's response to food also vary with the time of day. very