Decoding cravings: Why your body craves junk food

Ever feel like you just have to have a bag of potato chips right now? Or do you occasionally get an overwhelming urge to eat chocolate?

We all experience food cravings from time to time. Some of these cravings are triggered when we are tired, underfed or under–watered, but usually the root cause of our cravings is more complicated.

Though food cravings were once thought to be the result of vitamin and nutrient deficiencies, new research indicates that environmental and psychological factors are more likely culprits. Otherwise, our bodies would be screaming for spinach, apples and whole grains when we're running low on important nutrients.

Instead, researchers are finding that chronic stress, fatigue and dieting cause us to crave foods that stimulate reward circuits in the brain or foods linked to happy memories. Many of these foods are too sweet, too salty or too high in calories. (Think comfort food.)

Caving in to cravings for processed foods and high–calorie snacks can sabotage an otherwise healthy diet and cause creeping weight gain. However, figuring out what's behind your cravings can help you better control them.

Junk food catalysts

While the research is inconclusive about whether iron deficiency drives people to eat red meat or if a lack of magnesium leads to chocolate cravings, experts have found that something as common as too little sleep can make you more likely to indulge in junk food.

Using MRIs, researchers at the University of California Berkeley measured activity in the brains of healthy adults both after a good night's rest and after a sleepless night. They found that participants who did not sleep well were more likely to reach for high–calorie junk foods than healthy greens and whole grains the next day.

Chronic stress also causes many people to reach for fatty foods and sweets. Scientists believe these cravings are triggered when the body produces too much cortisol—a stress hormone.

Restrictive diets also can set up cravings for off–limits food. If you're on a very low–calorie diet or have banished certain foods from your plate, you're more likely to overeat high–calorie or banned foods when you stop dieting, according to studies by the University of Toronto and Tufts University.

Kick hankerings to the curb

Controlling food binges and urges to eat a jumbo bag of M&Ms or a cheese–slathered entrée is possible, but you'll need a little willpower and several go–to tactics. Some examples include:

• Drink water and then wait 30 minutes before giving into a craving. Many times, we mistake thirst or mild dehydration for hunger pangs.
• Exercise early. A 45–minute morning workout can reduce your motivation to eat throughout the day, according to scientists at Brigham Young University.
• Get your stress in hand. Deep breathing, meditation and adequate sleep can ease everyday stressors.
• Go ahead and indulge ... a little bit. Avoiding a "bad" food actually can fuel your cravings. Having a small, planned serving of your favorite ice cream once in a while can prevent you from eating half a carton when your willpower crumbles.
• Eat a balanced diet. Consuming high–fiber proteins like beans and legumes along with complex carbs like whole grains will keep your blood sugar stable and your tummy full.

Should I be worried?

In most cases, having food cravings is completely normal and can be addressed with some of the simple lifestyle changes outlined above. There are some cases, however, when a food craving could indicate a more serious health problem. For example, a sudden, insatiable craving for salt could indicate that your adrenal gland is out of whack. If you crunch on ice all day long, ask your doctor whether you should be tested for anemia. And if you find yourself eating things like clay, sand or other nonfoods, talk with your doctor about pica, an eating disorder that is more common in children, but can affect pregnant women and other adults.

No matter what type of cravings you may be experiencing, it's important to listen to your body and not ignore its signals. Talk to your doctor about your questions and concerns. They can help you identify possible causes of your cravings and recommend lifestyle changes and/or treatment options to help you feel your best.