Jingle bellies

This is just what you need, at the height of holiday party season: gross-out science about deep belly fat. But first, some encouragement.

Cyd Nelson and Suzy Wiley, both of Kansas City, Mo., both trim and fit, were briskly hitting the path around Loose Park on a recent sunny but chilly day.

“The goal is to walk all winter long,” said Wiley, breaking stride to answer a few questions. “I’m worried about footwear.”

“I think we’ll have to wear thermal socks,” Nelson said.

That’s the spirit.

In the annals of exercise research, increasingly the answer is “brisk walking.”

What’s the question? Most people think it has to do with exercising the heart or getting rid of love handles and saddlebags.

But scientists are finding it’s about belly fat – also known as visceral fat, the interior kind that’s snug up against your internal organs.

Yeah, yuck.

Put a glob of abdominal fat and a glob of thigh fat in a petri dish, add a little stimulation, and the two behave quite differently, says Dr. Tim Church, director of preventive medicine research at Pennington Biomedical Research Center in Baton Rouge, La.

“The belly fat produces three times the bad chemicals,” Church said. “And it’s kicking the liver right in the teeth.”

That visceral fat is a bad operator, adds Dr. David Robbins, endocrinologist and professor of medicine at the University of Kansas Medical Center.

“We’re beginning to understand that this central fat may be the primary villain in the production of diabetes and heart disease in adults,” Robbins says. “Fat in the abdomen is metabolically very active. It secretes fatty acids and 55 different hormones.”

Maybe a mice study from earlier this year will help elucidate.

A University of Michigan research team transplanted visceral fat in one group of mice and subcutaneous fat, the kind just under the skin, in another. In terms of promoting dangerous inflammation and encouraging atherosclerosis, the belly fat was the big winner.

“It’s our bellies that are killing us right now,” says Dr. Tracy Stevens, cardiologist with St. Luke’s Mid America Heart Institute. “Our bellies are causing our own disease.”

And this is where recent research about exercise and belly fat comes in.

A study reported this fall from the Fred Hutchinson Cancer Research Center in Seattle followed about 100 men and 100 women for a year. They were encouraged to increase their physical activity six days a week. They weren’t given a diet plan.

Women who increased their activity by 3,500 steps a day lost five pounds. Men doing the same lost 8 1/2 pounds. Participants who exercised the most decreased their belly fat by 10 percent to 20 percent.

The study points up the good news, Robbins says. Some people aware of the dangers of belly fat think it’s highly resistant to exercise. But visceral fat is actually quite sensitive to exercise and calorie reduction.

“That’s where you’re most likely to lose the weight,” he says. “These fat cells shut off very quickly.”

People look at ideal weight charts, figure they’re never going to get there and give up, Robbins says. Or they notice that their fatty folds of skin don’t seem to shed readily as they exercise and cut calories.

But even a small weight loss shuts down some very dangerous signals from belly fat cells, the kind that put people at risk of disease.

“So even losing five to 10 pounds can have a disproportionate benefit to your health,” Robbins says.

How do you know it’s in there, this visceral fat?

Various types of imaging scans would reveal it, but they’re not necessary. Basically, abdominal fat takes up space and pushes out, increasing your waist size.

“It’s not what you weigh, it’s where you weigh,” says Church.

It’s worth noting that some people who aren’t particularly overweight may have a false sense of security. Skinny arms and legs and loss of muscle can help keep your weight down, but if the stomach is growing, the danger is there.

Back at Loose Park, friends Nelson and Wiley were glad to hear about the research showing how readily abdominal fat cells succumb to exercise.

Add that to the several roles their walking routine serves, including cardio training for tennis and an important social one: the chance to chat.

And don’t underestimate the benefits of having an exercise partner.

“Especially during the holidays,” Nelson says, “it’s easy to forget to prioritize exercise.”