Can stress Make You Fat?

There's new research about stress and snacking the sheds light on the biology behind it and also shows how to combat the problem.

You are likely familiar with the fight-or-flight reaction to stress, triggered by the release of adrenaline. What you may not be familiar with is cortisol.

Cortisol is another stress hormone released at the same time as adrenaline. But unlike adrenaline, you won't usually feel the effects for an hour or so. What does cortisol do? It makes you want to eat!

"Cortisol is one of the most potent appetite signals we have," says nutritional biochemist Shawn Talbott, Ph.D. It can affect you in a couple of ways. First, cortisol may interfere with brains signals that control appetite and satiety. Second, cortisol may cause your brain to want sweets. Combine these two factors and it explains how you can crave dessert even after a big meal when you're feeling stressed.

Cortisol is the reason you feel like you've got no willpower. Cortisol wants high-fat, simple carbs like macaroni and cheese, chocolate brownies and those potato chips.

A study conducted at the University of Pennsylvania did a study on mice and found that they, too, gravitate toward high-fat foods in stressful situations. The mice were fed their regular diet but for one hour a day, they were also given as many high-fat food pellets as they wanted to eat. When the mice were exposed to the odor of a predator they gorged on as many as they could during that hour, and increased their consumption day by day.

The research from this study suggests that women are more inclined to react this way than men. In the study, a single high-fat food pellet was buried in the animals' bedding. It was the female mice who were more determined to find the pellet than the males, finding the pellet in half the time it took the male mice.

Men's and women's snacking habits are also different. In a study conducted at Montclair State University, a group of subjects were given puzzles, some impossible to solve, then were invited to bowls of snacks; peanuts, grapes, potato chips and M&Ms. When the women were able to solve the puzzles they chose the healthy snacks but ate the chocolate more often when they couldn't. The men were the opposite. They gravitated toward the unhealthy snacks when they could solve the puzzles. Debra A. Zeller, Ph. D., and the lead author of the study attributes the difference to what she calls "taboo" foods. Men reward themselves with junk food. The women, many of whom were on diets, grabbed the "taboo" foods when frustrated to make themselves feel better.

Neuroscientist Cliff Roberts, Ph.D., a senior lecturer with London Southbank University came to an interesting conclusion. "The more you try to restrict your calories the more likely you are to gain weight." He studied 71 healthy female students who were enrolled in a nurse practitioner program. During the 12 weeks from the beginning of the term until finals, 40 of the women gained an average of 5 ½ pounds. All women were habitual dieters who exhibited high restraint at the beginning of the term and all had significantly high cortisol levels. The added stress of trying to maintain their weight and keep up with their schoolwork created a vicious cycle: They were stressed, so they ate, gaining weight made them stress more, so they ate more.

Now that you have a better understanding of cortisol's effects, what can you do about it? Plenty!

Allow small treats. Zellner, of the Montclair study says, "Instead of viewing certain foods as 'off limits', they [women] should view them as things they can have occasionally." By budgeting one or two small treats into your day instead of avoiding them entirely, you are less likely to give up and binge eat.

Sleep. Shawn Talbot, Ph,D. observes, "A person who gets less than six hours of sleep can have up to 50 percent more cortisol in the evening than someone who gets eight hours." The journal Sleep reports that seven or eight hours of sleep is sufficient and that getting less could lead to weight gain.

Get a massage. Studies have linked massage to lower cortisol. In one study, a 15 minute chair massage decreased participants' cortisol levels by 24 percent.

Move. "Being active is a great way to reduce cortisol levels," Talbott says. "In our studies we see cortisol falling by 15 to 20 percent from the start to the end of a six- to twelve- week diet, exercise and stress-reduction program."


------------------------------