Americans don’t lack methods of dieting — South Beach, Atkins, Weight Watchers, Nutrisystem, Slim Fast, detoxing, juice cleanses — but not all are healthy.

With public health organizations and the media constantly remarking on the obesity epidemic in the U.S., new studies on approaches to start and maintain weight loss couldn’t come at a better time.

A new study conducted at Boston Children’s Hospital and published in the Journal of the American Medical Association compared the weight loss and subsequent weight maintenance of three popular dieting approaches — low-carb diets, low-fat diets and low-glycemic diets.

When someone decreases the amount of calories they consume, the body’s metabolism slows, reducing the use of calories and contributing to weight gain.

This can work against the goal of losing weight and keeping it off. So researchers examined the affect of these popular dieting approaches on long-term weight loss.

The Boston study followed a group of overweight and obese adults aged 18 to 40 for 10 weeks. After achieving an initial 10 to 15 percent weight loss, researchers placed subjects on one of the three diets and looked for changes in their metabolism and weight maintenance.

These diets were isocaloric, meaning all subjects consumed the same number of calories despite being on the different diet plans.

The low-carb diet had the most pronounced effect on metabolism with the best resting energy expenditure and total energy expenditure. But the low-carb diet also resulted in some undesirable side effects, like high levels of the stress hormone cortisol, which can lead to diabetes, and biochemical markers like CRP, which are associated with inflammation and heart disease.

Similarly, the low-fat diet produced the hormone leptin, which is associated with hunger and could lead to weight gain.

In contrast, the low-glycemic diet allowed stable blood sugar and metabolism levels without elevations in stress hormones and other negative biochemical markers.

What type of food a person eats affects their metabolism, and a person’s metabolic index determines how many of those calories will be burned.

The low-glycemic diet derives 40 percent of calories from carbohydrates, 40 percent from fats, and 20 percent from proteins. The diet uses a number of fiber-rich foods like beans, non-starchy vegetables, fruit, and whole grains; lean protein sources like fish and skinless poultry; and healthy fats from nuts, avocados and certain vegetable oils. These foods require a longer time to digest and absorb, leaving people feeling fuller for a longer time.

The main conclusion of this study is that a calorie is not just a calorie in the context of weight loss or maintenance.

Successful dieting and weight maintenance requires behavioral modifications in addition to caloric restriction, and individuals should consult their physicians about their weight-loss goals and diet plans.

Professors Norbert Herzog and David Niesel are biomedical scientists at the University of Texas Medical Branch. Learn more at

(1) comment

George Croix

With all the 'new normals' being touted for a 'fundamentally changed' nation, maybe everybody should just cultivate about 3 stomach rolls minimum, at least a double chin, and a rear that looks like 50lbs of chewed bubble gum. Fit right in with what one sees waddling around daily in stores. Add Spandex and 3 sizes too small tee for maximum visual effect. Replace the Star Spangled Banner with the sound of massive thighs rubbing together for our nation's benchmark anthem.
Losing weight is not easy, or pleasant, or facilitated by just reading a book or article, and each person is affected differently in their efforts, because each person IS different. If you really don't like the 'new normal', then stop whining and DO something about it. You don't need Nutri-Anything. You need self-control and determination. You will not starve to death just because you are hungry, and you will not lose weight unless you are hungry, at least for the time it takes you to adjust to dropping off that tonnage at a steady rate.
Basic start: Eat significantly less than you usually do, and get up off your fat behind and move a lot more than you usually do, and keep a daily log of every bite you shove into that gaping maw that was once a normal sized mouth.
Mainly, don't even bother to start unless you see your efforts as a lifetime change, not just a goal to be reached.
Imho, after 28 years of keeping the 60 extra pounds started with off.
Until you come to the realization that it's not those jeans that make your rear look huge, it's your huge rear inside them, you will not succeed.

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