More on visceral fat from the Chronicle today
Big belly may be matter of stress
Experts test if relaxation techniques aid in trimming abdominal fat
Erin Allday, Chronicle Staff Writer
Monday, January 15, 2007
In the world of metaphorical body image, apples are not the fruit of choice.
People with "apple-shaped" bodies -- usually defined by a thick waist or a pot belly -- are more likely to have the most dangerous kind of fat in their abdominal cavities than those with a pear shape, in other words, those who carry their weight in their thighs, hips and butts.
The difference between the two physiques may be a matter of stress.
Recent research has suggested that abdominal fat is related to a hormone released when we're under stress, and now UCSF researchers are looking for 50 overweight women to participate in a study on stress-relief techniques and body fat.
The goal isn't necessarily to help the women lose weight, but to see if easing stress helps reduce abdominal fat -- and lower the risk of heart disease, stroke and type 2 diabetes.
"We hope they will lose fat in general, but we're not as concerned with whether they lose weight as read on a scale," said Elissa Epel, an assistant professor of psychiatry at UCSF and an expert on the physiological effects of stress. "We are really focusing on improving these women's health through reducing their visceral fat. Where you store the fat is really important."
The fat in a pot belly or a thick waist is not particularly unhealthy, Epel said. But having fat in both areas is a sign of too much visceral fat deep in the abdominal cavity, surrounding internal organs. Doctors don't yet know exactly why visceral fat leads to a greater risk of heart disease and diabetes, but it could have to do with the proximity to the liver and a complex process that promotes atherosclerosis, or hardening of the arteries.
A person doesn't have to be overweight to have too much visceral fat. For example, a woman could be very lean but have a small pot belly that suggests visceral fat lies underneath. Asian Americans in particular are prone to putting on abdominal fat while still looking slender, doctors say. The key is to look at the waist-to-hip ratio -- if the waist is wider than the hips, that could mean trouble.
For years, researchers -- along with pretty much anyone who's ever tried to lose weight -- have known there's a tie between stress and fat. Of course, everyone reacts to stress differently, and the same stress that may drive one person to snack may make someone else lose his or her appetite for reasons that remain a mystery to researchers.
Still, many people overeat when they're stressed, and they're more likely to grab a bag of potato chips than baby carrots. But only recently has the connection become better defined and identified as a complex biochemical reaction.
Specifically, cortisol, a hormone that is released when people are under stress, seems to work with insulin to create visceral fat, Epel said. At the same time, cortisol prompts people to crave "comfort foods" -- anything with sugar or fat in it.
At one time in human evolution, such a response to stress would have made sense -- back when "stress" meant drought or famine, among other life-threatening disasters, and sugary, fatty foods would supply energy needed for survival, said Mary Dallman, a professor of physiology in the neuroscience program at UCSF, who has studied the effects of chronic stress.
"A lot of the stress response seems to be about the body being prepared to fight or flight. Your body is doing exactly what it's supposed to do, but our society has gotten a bit ahead of it," Dallman said. "You can work around (the stress response). You can go for a bike ride, read a book, get away from what's pissing you off. And then after a little quiet time you can (safely) look at grabbing something and putting it into your mouth."
When researchers first began identifying the link between cortisol and food cravings, naturally dieters jumped on a potential weight-loss strategy -- drugs designed to reduce or counteract the cortisol. But it's not that simple, many doctors say.
It all goes back to the idea that a person can be thin and still have too much visceral fat. Cortisol alone doesn't necessarily cause people to gain weight, it just helps them create the wrong kind of fat.
That's why the researchers in the UCSF study aren't promising weight loss to their study participants.
In the study, 50 women will be divided into two groups, one of which will start stress reduction classes right away, the other in six months. The study is focusing on women because they are more likely to turn to comfort foods in times of stress.
The women will learn stress-relief techniques in weekly classes, and also will be taught to recognize the triggers that prompt them to turn to comfort foods, and how they can avoid those triggers.
They also will learn to meditate with their food in a practice called "mindful eating," said Jennifer Daubenmier, a postdoctoral fellow with the UCSF Center for Obesity Assessment, Study and Treatment, who is leading the study with Epel. For example, participants might be asked to eat one piece of fruit every day and take notes on how the fruit smells, how it's shaped, the texture of its skin and how they're feeling while they eat it. The goal is to get them thinking about how and why they eat, and ultimately help them make smart food choices.
The women will not be told to change their diet or exercise routines. But ideally, at the end of three months of classes and six months of study, the women will have lost visceral fat, Daubenmier said.
"Weight loss is not the goal," said Daubenmier. "But we are thinking we will find a reduction in the visceral fat, which is really important. We're looking at breaking that stress-eating link."
How to qualify for UCSF's study
Women must weigh less than 300 pounds and have apple-shaped figures. They must be between the ages of 21 and 50 and not recently pregnant. They must not be diabetic or have heart disease.
Anyone interested in participating should e-mail
[email protected]. The study is being funded by the Mount Zion Health Fund.
Determine your shape
How to find out if you have an apple-shaped body:
-- Measure the circumference of your waist, then your hips.
-- Divide the circumference of your waist by that of your hips.
-- If you're a man and the number is greater than 1, you have an apple shape and may have too much belly fat. For women, who have wider hips, you may have too much belly fat if the number is greater than 0.8.
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