New Weight-Loss Focus: The Lean and the Restless. Lose Weight While You Veg

ROCHESTER, Minn. - If you move, they will measure it. If you don't move, they will measure that, too, along with what you eat. There are no secrets here, at least no metabolic ones. Not only do they have your number - they have 25 million of your numbers.

They, in this case, are scientists at the Mayo Clinic here. And they learn your secrets only if you have been one of the select few to wear a set of underwear with racy-looking cutouts at the crotch and backside, and pockets holding position and motion sensors dangling a half dozen tangled wires.

In January, the scientists here who designed the underwear reported a striking difference in activity levels between lean people and overweight ones. Their study, published in Science, did not involve deliberate exercise, but it measured - with the help of the sensors - how much people moved about naturally and spontaneously.

The heavier ones tended to sit, while the lean ones were more restless and spent two more hours a day on their feet - standing, pacing around and fidgeting. The difference translated into 350 calories a day, enough for the heavy people to take off 30 to 40 pounds a year, if they would get moving.

The researchers believe the tendency to sit still or move around is biological and inborn, governed by genetically determined levels of brain chemicals. And that tendency influences weight - not the other way around, the researchers say.

The Mayo researchers call the type of movement and calorie burning that they study NEAT, for nonexercise activity thermogenesis. The leader of the research team, Dr. James Levine - a nutritionist, an endocrinologist and a professor of medicine - has defined the term as "the energy expenditure associated with all the activities we undertake as vibrant, independent beings." Those activities include "occupation, leisure, sitting, standing, walking, toe-tapping, guitar playing, dancing and shopping," he writes. His team has even measured the energy burned in gum-chewing (11 calories an hour, if you chew six pieces at a time).

"This is probably the only place in the world that can do this kind of research," Dr. Levine said.

Other researchers have praised the work, particularly the team's painstaking and precise measurements of calories consumed and the way they are burned.

Dr. Rudolph Leibel, an obesity researcher at Columbia University, called the Science paper "great," and added, "I believe the data; it's done correctly and an interesting set of findings."

Nonexercise activity can account for a significant portion of the calories burned in a day, anywhere from 15 percent in a sedentary person to 50 percent in someone who is very active. Standing takes more energy than sitting, and strolling along at just one mile an hour burns twice the calories of sitting.

Dr. Levine and his colleagues believe that if scientists can understand nonexercise activity better and identify what drives it, what makes people want to move around, they may be able to harness it to help the millions who are struggling to control their weight.

"Can we really find something to help people?" Dr. Levine asked. "We want to examine how to change people's NEAT. There is this gap. Can we close it?"

He advocates this approach because the usual weight loss remedies usually fail. People have a hard time sticking with exercise programs and diets, and Dr. Levine argues that the very number of diet books and weight-loss plans is proof in and of itself that none of them work. "If one worked, we'd all be following it," he said.

Studying activity and metabolism in people and animals has been a lifelong fascination, Dr. Levine said, explaining that he started measuring movement in snails and bacteria during his boyhood in London. He trained in medicine there, came to the Mayo Clinic as a resident in 1992 and then joined the faculty.

Today he runs a research group with a dozen scientists, specialists in physiology, nutrition and computing. They study nonexercise activity not only in obese adults and children, but also in the elderly, people with anorexia nervosa and populations threatened by starvation in Africa and India.

They have even investigated the significance of chubby cheeks, noting that people who deposit fat in their faces tend also to build up harmful stores inside the abdomen, which are linked to heart disease. Some members of the team also work with animals, trying to characterize the rich palette of brain chemicals that control activity levels and weight.

Although he spends most of his time on research, Dr. Levine is still a practicing endocrinologist who treats patients one afternoon a week, and he says he sees firsthand how intractable obesity can be, and what physical and emotional suffering it can cause.

Many of his patients are very obese. One was so heavy she could barely get out of a wheelchair, he said. He suggested an initial goal of simply standing up three times a day, and then trying to walk for 15 seconds at a time. For her, working her way up to two minutes of walking was a major milestone, he said.

Obese people are so stigmatized that even some doctors, perhaps unconsciously, withdraw from them, Dr. Levine said, noting that patients have told him he was the first physician who ever shook their hand or actually examined them.

"The key is to provide a nonjudgmental, compassionate environment," he said.

The study published in January included 10 lean men and women and 10 slightly obese ones, all of whom described themselves as "couch potatoes" who did not exercise much. The object was to measure and compare their nonexercise activity, and also to determine whether it changed when they were put on special diets that made them gain or lose weight.

They wore the special underwear, which measured posture and movement every half second around the clock for 10 days in a row on several occasions, yielding 25 million points of data on each participant.

To make sure the researchers knew exactly how many calories the subjects were eating, dietitians prepared all their food for weeks at a time, a total of 20,000 meals.

"These studies cost a fortune," Dr. Levine said. Each costs hundreds of thousands of dollars, paid by grants from the National Institutes of Health.

"Every food item is weighed to within a gram, and each meal costs $30," he said.

In addition, the 20 participants were paid $6,000 each for their time. And the overweight ones were given advice and personalized plans to help them lose weight.

This was the study that found that the lean subjects spent much more time on their feet than did the obese ones.

What convinced the researchers that the tendency to be inactive led to obesity, and not the other way around, was that the activity levels did not change when the diets were altered to make the obese people lose weight and the lean ones gain it. If the common wisdom were true - that being heavy is what makes people sluggish - then the overweight people should have acted more energetic when they lost weight, and the lean ones should have slowed down when they gained.

But that did not occur.

If activity levels are governed by biology, then it may seem hopeless to try to change them, Dr. Levine acknowledged.

"But the counterevidence to that is, our biology as a species really hasn't changed in decades and centuries, and yet obesity rates have dramatically increased in the last 15 years," he said.

Activity levels have declined, and he and many other obesity researchers say that decline, more than increases in eating, is to blame for rises in obesity.

What has changed is the artificial environment: there is far more opportunity today than in the past to be sedentary. And some people may be genetically predisposed to seize that opportunity.

"We all like and dislike different things," Dr. Levine said. "None of us can quite quantify it."

In a biological way, not a personal one, he said, obese people seem to like inactivity.

"Given an environment that lets people sit for hours and hours a day, they will," he said.

A solution, then, may be to change the environment, to make moving around easier and sitting still less convenient.

The team's recent paper in Science noted, for instance, that in 1920 before cars were common, people in Rochester walked an average of 1.6 miles a day to and from work, which burned about 150 calories a day. Few people do that today; many live too far away to talk to work, but, Dr. Levine suggests, many could build short walks into the day.

This is not a new idea, he acknowledges. Plenty of experts have been advising people to find small, relatively painless ways to burn extra calories, like taking the stairs instead of the elevator and parking at the far end of the lot to make themselves walk a bit.

But for this kind of thing to make a real difference, people would have to commit to changing their habits and their environment. When it comes to this mission, Dr. Levine may be his own best guinea pig.

"If anyone in the world is going to do this it's obviously going to be me," he said.

At meetings, he stands instead of sitting. Talking on the telephone, he paces around. In his office he has a treadmill in place of a desk. He got it last year when he saw the data from the study comparing lean people and obese ones.

"My computer is stationed over the treadmill," he said. "I work at 0.7 miles an hour."

A stand-up desk might seem simpler, but he prefers the treadmill.

"Standing still is quite difficult," he said. "You have a natural tendency to want to move your legs. Zero point seven is the key. You don't get sweaty, you can't jiggle too much. It's about one step a second. It's very comfortable. Most people seem to like it around 0.7."

He has installed a second treadmill alongside his own, and he encourages visitors to hop on and stroll while they talk to him. It takes some getting used to, but, he says, envious colleagues at Mayo have been clamoring for treadmill desks.

"Walking at work, first of all it's addictive," he said. "It's terribly good fun. I actually feel happier, particularly in the afternoon. You might think you come home exhausted, but you don't. You come home energized."

For him, the treadmill has eliminated the afternoon slump, when a lot of people feel sleepy and crave candy bars or caffeine.

"I've become convinced we really can generate an office environment where people are on the move and are happier," he said.

By DENISE GRADY