Is your diet passé?

When Oprah Winfrey confessed last month that she'd failed to stick to her diet and was again tipping the scale at 200-plus pounds, millions of failed dieters could relate. Their futile efforts are not for lack of weight loss programs and products that drive a $58 billion US industry, according to market researcher NPD Group.

The abundance of information, however, often leaves dieters confused about competing claims.

That's where science can help. Over the past few months, new scientific literature has addressed the usefulness of restrained eating and diet counseling, as well as the notion that eating is an instinct beyond our control.

The research confirms what most don't want to accept: dieting requires both restraint and discipline.

The latest research

Dr. Larry Tucker, a professor of exercise science in the College of Health and Human Performance at Brigham Young University, authored a study on restrained eating that appeared in the Jan./Feb. 2009 edition of The American Journal of Health Promotion. Tucker spent three years studying the eating habits of 192 middle-aged women.

Some participants practiced what's known as restrained eating, or the conscious effort to avoid unhealthy foods and substitute them with healthier ones. Previous short-term studies have demonstrated a link between restrained eating and binging, leading researchers to believe that limiting choices often results in overcompensation later.

Tucker's study draws the opposite conclusion. The women who did not practice restrained eating were almost two-and-a-half times more likely to gain weight over the three-year time period than those who were more selective. While the phenomenon of restrained eating and binging has puzzled researchers for years, Tucker believes the length of his study demonstrates a strong causality between eating selectively and weight maintenance. This conclusion has been supported by other long-term studies.

The lesson, he says, is simple and one that dieters often fear: "We can't eat freely."

While it's a harsh truth, Tucker says people can adapt to it by making various changes to their habits. Weigh yourself several times per week and keep a food diary, he advises. Added calories, and pounds will show up quickly on the page and scale.

If such changes seem too overwhelming, consider consulting a registered dietitian or counselor.

Another recently released study supports this approach.

The six-month study, published in the Dec. 2008 issue of the Journal of the American Dietetic Association, was conducted by University of Michigan research professor Dr. Zora Djuric. She followed 69 women between the ages of 25 and 59 as they tried to switch to the Mediterranean diet, which is rich in vegetables and fruits and low in polyunsaturated fats like margarine and corn oil. The diet has been linked to lower cancer rates.

Despite its benefits, the required seven to nine servings of fruits and vegetables per day and increase in monounsaturated fats like olive oil and hazelnuts can be difficult for Americans accustomed to eating far less from those food groups.

One group received weekly and bi-weekly telephone counseling from registered dietitians. They were also given an "exchange" list that translated the necessary food groups (dark green vegetables or green herbs, for example) into specific items (broccoli and basil). The other group received no additional guidance.

Those who got counseling doubled their intake of fruits and vegetables and increased their intake of monounsaturated fats while the other group saw no significant changes.

"There's evidence that whenever you supply regular support to people they can make big changes to their diet," observes Djuric.

The average dieter can find a registered dietitian through the American Dietetic Association, but some companies offer free weight loss counseling through employee assistance programs.

Managing your instincts

While these studies are encouraging, their conclusions may still leave some dieters feeling helpless.

Dr. Susan Roberts, a professor of nutrition at Tufts University and author of the recently released book The Instinct Diet, offers hope with advice based on nearly 20 years of clinical research.

She argues that five basic survival instincts direct our eating patterns. They include hunger, variety and calorie density. It doesn't help that our bodies are primed with chemicals like the neurotransmitter dopamine that sends out reward signals to the brain when we eat high-calorie foods.

But Dr. Roberts says instincts can be controlled. Her tested recommendations include eating on a regular schedule, distracting the mind from cravings and controlling your "food environment."

Routine meals prevent hunger binges and also teach the brain when to expect food. This strategy even works with indulgences: If the brain learns to expect bacon on Sunday morning, it will stop sending out signals to trigger a craving at other times. You can also quell a craving by calling a friend or drinking a full glass of water, which makes a person feel full.

It helps to control your exposure to fattening foods. Instead of leaving ice cream in the freezer, for example, replace it with a healthier snack like frozen berries and indulge in ice cream once a week outside the house.

Roberts acknowledges that dieters battle constant challenges from the outside world.

"We're in this culture where people are supposed to be good and mindful, but our food brain isn't sensible," she explains. "We are machines designed to respond to our environment."

The secret to success, she says, is reprogramming the responses and changing the setting.