Friday, July 20, 2012

Science behind low glycemic diet: All calories are not equal

The following is an excerpt of an article published by Science Daily on 6/26/2012:
A new study published June 26 in the Journal of American Medical Association challenges the notion that "a calorie is a calorie." The study, led by Cara Ebbeling, PhD, associate director and David Ludwig, MD, director of the New Balance Foundation Obesity Prevention Center Boston Children's Hospital, finds diets that reduce the surge in blood sugar after a meal--either low-glycemic index or very-low carbohydrate-may be preferable to a low-fat diet for those trying to achieve lasting weight loss. Furthermore, the study finds that the low-glycemic index diet had similar metabolic benefits to the very low-carb diet without negative effects of stress and inflammation as seen by participants consuming the very low-carb diet.
Interesting, right?

So, what Dr. Cara Ebbeling is saying is that counting calories, fat and carbs is not the best way to lose weight and expect to maintain weight loss. 

Traditional diets like Jenny Craig and Weight Watchers ARE effective.   Both of these diets are all about portion control.  They are effective because they offer their customers an easy way to monitor their portion control... and both are very clear... that they are life style changes.   So whether you are purchasing food from Jenny Craig or counting points with Weight Watchers, you need to know... that once you lose the 20 - 40 or even 100 pounds... you will need to continue to either count the points or purchase the food to keep it off... because out in the wild...  you will gain the weight back.

 According the the article in Science Daily, "After weight loss, the rate at which people burn calories (known as energy expenditure) decreases, reflecting slower metabolism. Lower energy expenditure adds to the difficulty of weight maintenance and helps explain why people tend to re-gain lost weight.

I didn't know that.  SO............

That's why the weight always seems to come back ... and come back double...

Here's the rest of the article... it's really very interesting:

The study suggests that a low-glycemic load diet is more effective than conventional approaches at burning calories (and keeping energy expenditure) at a higher rate after weight loss. "We've found that, contrary to nutritional dogma, all calories are not created equal," says Ludwig, also director of the Optimal Weight for Life Clinic at Boston Children's Hospital. "Total calories burned plummeted by 300 calories on the low fat diet compared to the low carbohydrate diet, which would equal the number of calories typically burned in an hour of moderate-intensity physical activity," he says.
Each of the study's 21 adult participants (ages 18-40) first had to lose 10 to 15 percent of their body weight, and after weight stabilization, completed all three of the following diets in random order, each for four weeks at a time. The randomized crossover design allowed for rigorous observation of how each diet affected all participants, regardless of the order in which they were consumed:
  • A low-fat diet,which reduces dietary fat and emphasizes whole grain products and a variety of fruits and vegetables, composed of 60 percent of daily calories from carbohydrates, 20 percent from fat and 20 percent from protein.
  • A low-glycemic index diet made up of minimally processed grains, vegetables, healthy fats, legumes and fruits, with 40 percent of daily calories from carbohydrates, 40 percent from fat and 20 percent from protein. Low glycemic index carbohydrates digest slowly, helping to keep blood sugar and hormones stable after the meal.
  • A low-carbohydrate diet, modeled after the Atkins diet, composed of 10 percent of daily calories from carbohydrates, 60 percent from fat and 30 percent from protein.
The study used state-of-the-art methods, such as stable isotopes to measure participants' total energy expenditure, as they followed each diet.
Each of the three diets fell within the normal healthy range of 10 to 35 percent of daily calories from protein. The very low-carbohydrate diet produced the greatest improvements in metabolism, but with an important caveat: This diet increased participants' cortisol levels, which can lead to insulin resistance and cardiovascular disease. The very low carbohydrate diet also raised C-reactive protein levels, which may also increase risk of cardiovascular disease.
Though a low-fat diet is traditionally recommended by the U.S. Government and Heart Association, it caused the greatest decrease in energy expenditure, an unhealthy lipid pattern and insulin resistance.
"In addition to the benefits noted in this study, we believe that low-glycemic-index diets are easier to stick to on a day-to-day basis, compared to low-carb and low-fat diets, which many people find limiting," says Ebbeling. "Unlike low-fat and very- low carbohydrate diets, a low-glycemic-index diet doesn't eliminate entire classes of food, likely making it easier to follow and more sustainable."


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