Low-carb diets: How do they shed the pounds?

The “low carb” diet theory, promoted relentlessly for more than 30 years until his recent death by Dr. Robert Atkins, is now being followed by an estimated 17 percent of Americans, according to the latest ACNielsen Homescan Survey.

The South Beach Diet, last year’s runaway diet book phenomenon, which is based on the same theory but includes a wider variety of foods, has sold over 5 million copies.

A low-carb diet is based on the theory that over-consumption of carbohydrates, and the way our bodies process them, is the key factor in obesity. The premise of eating “low carb” as a tool to losing weight is that the body’s cells that convert carbohydrates into glucose (which becomes energy) does not work correctly in many overweight people. In these cases, said Atkins, a symptom called “insulin resistance” comes into play. Atkins’ program suggests that by reducing carbohydrate intake to less than 40 grams a day, our bodies shift into a process called “ketosis,” in which we burn fat as fuel. The current Recommended Daily Allowance for carbs is set at 300 grams a day, but The Institute of Medicine has just submitted their recommendation that it be lowered to 130 grams a day for healthy adults and children over 4.

TODAY low-carb special Low-carb fast food: The latest trends Atkins-style offerings are all the rage at the nation’s restaurants. Here are some of the newest offerings, including a crustless pizza. Watch out! ‘Low-carb’ label may mean nothing Restaurants are rushing to come up with Atkins-style menus. However, there is no official definition of what ‘low-carb’ is… Low-carb diets: How do they shed the pounds? About 20 percent of Americans are on some variety of the regimen developed by the late Dr. Robert Atkins. Here's how they work: Want to be a low-carb success? Some top tips Don't waste your weight-reduction efforts. 'Today' show contributor Phil Lempert has some quick advice to do the most effective job

This form of diet is based on restricting processed and refined carbohydrates and limiting the consumption of sugars, breads, pastas and starchy vegetables. The diets differ when it comes to recommending just how low carbohydrate intake should be – some go as low as 20 grams a day, while others suggest 60 grams a day.

The established medical community, in the form of the prestigious New England Journal of Medicine, went some way to vindicating the Atkins diet a couple of years back when it published findings, based on two studies, that showed Atkins dieters lost twice as much weight loss as those on a low-fat diet over a six-month period. (They also found, though, that those on Atkins tended to regain about a third of their weight, as opposed to one-fifth for the low-fat group.)

Not all researchers, however, agree with the idea of a strict “low carb” diet, arguing that a more balanced nutritional regimen – including a small reduction in carbs -- is more beneficial overall. New research from the Human Nutrition Center on Aging at Tufts University in Boston points out that unrefined whole grains, such as whole-wheat flour, brown rice, barley and oatmeal, both do not contain as many carbs as more processed products and also provide benefits, such a possible reduction in the risk of diabetes.

For more information about the low-carb products, visit Phil’s website at www.supermarketguru.com. You can e-mail Phil directly at Phil.Lempert@nbc.com

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