The Science of Weight Loss

  • Posted: Thursday, August 2, 2012 12:01 a.m.
    UPDATED: Thursday, August 2, 2012 12:51 p.m.

The low-carb craze came and went. That's no surprise to weight-loss researchers who have been conducting studies at universities and major research centers to target what really works to shed pounds and keep them off and reduce the public health threat of obesity.

"Low-carb diets have been in and out of favor since 1949, and over the years we've learned that they don't work very well in the short- or the long-term," says Daniel S. Kirschenbaum, PhD, director of the Center for Behavioral Medicine and Sport Psychology in Chicago and author of The Healthy Obsession Program.

The theory behind low-carb diets is that carbohydrates raise blood sugar levels, which causes a release of insulin. Insulin allows blood sugar to enter the cells, which use it for fuel. If you eat only a few carbs, diet proponents say, your blood sugar will be lower and your body will be forced to use stored fats as fuel. This will lead to weight loss.

Weight loss does occur on a low-carb diet. Researchers give several possible reasons for this:

When your body burns stored sugars and fats for fuel, water is released. This water is what accounts for the weight loss.

When your body burns stored fats, the byproducts are substances called ketones. Ketones decrease appetite in some people.

Most low-carb diets are also low in calories.

The balance of diet studies shows it's not carbohydrates specifically that count, but the total calories and fat consumed.

Here are proven strategies that Dr. Kirschenbaum recommends based on more than 50 years of scientific data.

Don't go it alone Research shows social support is a powerful weight-loss tool. A recent University of Pittsburgh School of Medicine study, for example, found people who involved friends or family in their plan lost more weight and kept it off longer than those who tried to shed pounds solo.

"Making weight loss public also tends to increase commitment. If nobody knows about your plan, it's easier to erase," says Dr. Kirschenbaum.

Develop intermediate goals It's common for people trying to lose weight to have an objective, such as trying to lose a certain number of pounds in a month. But that's not enough to get the job done.

Instead, focus on goals that will lead to your objective, says Dr. Kirschenbaum. These goals might be wearing a pedometer and trying to walk 10,000 steps each day, or keeping a food and exercise diary.

Get tough on yourself Speaking of goals, it's also better to have a more stringent one, such as "I will exercise every day," than a more moderate goal, such as "I will exercise four days a week," says Dr. Kirschenbaum. "Moderate goals may seem more achievable, but studies show they're not as effective."

With exercise, for example, when you aim for the tougher goal of exercising daily, exercise becomes more habit-forming than when you allow yourself to skip days.

Similarly, with diet, it's more effective to limit your fat intake to no more than 10 percent of total calories than trying to cut back to 30 percent of total calories or less.

Restrict problem foods For a time, the notion that you shouldn't restrict certain foods because you'll just crave them more and binge was the conventional wisdom. But studies show those who actually tried that method gained weight.

"The reality is that you just can't give yourself permission to eat problem foods," says Dr. Kirschenbaum. "Effective weight controllers restrict them and eat other things that are lower in calories and fat but are comparable in taste, such as chocolate sorbet instead of chocolate ice cream."

What if you eat something that's not in line with your goals?

"Go ahead and feel the pain of disappointment, then write down what you ate, consider the situation that led you to overeat and try to understand why it happened," says Dr. Kirschenbaum. "Successful weight losers consider a lapse an incident rather than a tragedy or 'cheating.' A problem-solving approach reinforces your self-regulatory skills and gives you an empowering feeling of control."

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