Northwest Health | SPRING 2009 By Pamela Richardson

It's 3 p.m. Your eyelids are heavy, and there's a familiar gnawing feeling in your stomach. What sounds better to you: the cookie you bought at lunchtime or the tired-looking carrot sticks in the refrigerator? You're not alone if you reach for the cookie — and there's a reason for that.

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Eating what we want, when we want it, is practically a constitutional right for many Americans. Unfortunately, what we want has been hardwired into our bodies for eons, and it's rarely carrot sticks. The Centers for Disease Control and Prevention recently dubbed American society "obesogenic" — an environment that promotes overeating, unhealthy foods, and lack of physical activity.

"The fact that one-third of adults and 16 percent of children in the United States are obese is the result of a complex combination of how our bodies work and an environment full of very convenient, energy-dense foods," says obesity expert David Arterburn, MD, MPH, investigator at Group Health Center for Health Studies. "Our body's triggers for hunger are simply stronger than the drives that make us feel full."

Your Body's Instincts: Food = Survival

Early humans developed hunger as a means of ensuring adequate fuel for their bodies. When we get hungry, the sight or smell of food increases the flow of blood to pleasure centers in the brain, and the stomach produces more ghrelin, which is a hormone that stimulates appetite.

Also see: 5 Steps for Curbing the Urge

Everybody has a unique pattern of ghrelin levels rising and falling in their bodies every day. If you aren't hungry in the morning, but are ravenous at lunchtime or at midnight, there's a physiological explanation. It's not that you aren't trying hard enough to control your eating urges, or that you lack willpower.

"Foods with a lot of sugar and fat stimulate the brain in a way that's similar to opiates like morphine," says Dr. Arterburn. "You see these foods and you associate eating them with a calm feeling or a sense of relaxation. People who are addicted to opiates have similar feelings about those drugs."

Some people can successfully retrain this urge by finding a replacement that stimulates the brain in the same way, like exercise. Sounds crazy, but the next time you want a sugary, fatty snack, try a brisk walk or exercise routine instead. Exercise stimulates the production of endorphins, which are natural opiate-like chemicals in the brain that increase pleasure and minimize pain.

Sleep also affects appetite. Lack of sleep prompts the stomach to produce more ghrelin (the hunger hormone) and less leptin, a hormone that makes you feel full. This means you may feel hungry, even when your body has had quite enough. The answer is simple: Get more rest. Most adults need between seven and nine hours of sleep every night.

An Alternative Response to Stress

Your body doesn't know the difference between getting a past-due credit card statement and swimming a river surrounded by snapping alligators. Both can cause stress, resulting in increased levels of cortisol (the "fight or flight" response) in the blood.

Using food to deal with stress is, again, a natural response to the brain's desire for pleasure and the return to a relaxed state. But anything that brings you personal pleasure, inspiration, or a sense of well-being may work as a calorie-free destressor. For example, try listening to music, getting a massage, reading, meditating, gardening, or playing with your children or pets.

The Key to Healthier Eating: Be Mindful

"If you're not thinking about what you're eating on a daily basis, you're probably gaining weight," says Dr. Arterburn. "As little as 100 extra calories a day — that's a small soda — can add up to five extra pounds at the end of the year."

Dr. Arterburn recommends keeping a food diary. Record what you eat, including beverages and condiments, and the approximate calories. The USDA National Nutrient Database can help you search for calorie (kcal) counts by keyword. Or order "The Doctor's Pocket Calorie, Fat and Carbohydrate Counter," by Allan Boruschek, available at the Group Health Take Care Store. Then start reading labels for calorie counts — and don't forget to factor in serving size.

"I think people started to equate fat-free with calorie-free, and began paying less attention to serving sizes, which have continued to grow," says Dr. Arterburn. "Counting calories is the only way to know if you're overeating."