Obese people ‘biologically driven to sit around more’

OBESE people are simply unable to get off their backsides, scientists said yesterday.

Researchers who studied every tiny movement of a group of volunteers, down to the smallest tap of a toe, found that overweight individuals sit around more than those who are lean. What is more, they cannot help it. Some people seem biologically driven to avoid unnecessary movement while others cannot keep still.

The findings emerged from a bizarre study in which volunteers wore special hi-tech underwear fitted with electronic sensors.

Scientists at the Mayo Clinic in Rochester, Minnesota, USA, discovered that everyday activity - which might include walking, shopping, tidying the bedroom, or just restlessly fidgeting - made a far greater difference to weight than was thought.

Obese individuals sat, on average, 150 minutes more each day than their naturally lean counterparts. As a result, they burned 350 fewer calories each day than slim people.

The study, which took more than 150 researchers 10 years to plan and carry out, focused on “non-exercise activity thermogenesis”, or “Neat” - the amount of energy used up by non-exercise activities.

May Clinic endocrinologist Dr James Levine said: “Our patients have told us for years that they have low metabolism, and as caregivers, we have never quite understood what that means: until today.

“The answer is they have low Neat, which means they have a biological need to sit more. A person can expend calories by going to the gym or through everyday activities. Our study shows that the calories that people burn in their everyday activities - their Neat - are far, far more important in obesity than we previously imagined.”

A total of 20 volunteers who lived and worked in Rochester took part in the study. All were self-confessed “couch potatoes” who said they led sedentary lifestyles, but 10 were lean and 10 mildly obese.

The special undergarments incorporated technology used in fighter jet cockpits. Sensors were embedded in the underwear, designed for both men and women, which allowed monitoring of body postures and movements every half a second, 24 hours a day for 10 days.

Fresh undergarments were issued each morning at the hospital where the participants ate all their meals, which were prepared by the scientists.

At the same time, data recorded by the sensors was downloaded into a computer.

“This instrumentation appears slightly bizarre as it gives us a covert window into people’s energetics and every activity in a completely unthreatening way,” said Dr Levine. “But because of it, we have a window into people’s activity life that no one’s ever had before.”

The findings, which appeared yesterday in the journal Science, showed that on average lean individuals stood about two hours longer each day than obese individuals.

The scientists concluded that certain people were born to be more active than others.