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Entries in Low Calorie (3)

Monday
Sep192011

Brains of Obese People May Show Less Impulse Control for High-Calorie Foods

David De Lossy/Thinkstock(NEW HAVEN, Conn.) -- The ability to fight food cravings may be all in your head, according to a new study published in the Journal of Clinical Investigation.

By manipulating blood sugar levels in study participants and monitoring their brains with functional MRI scanners, researchers from Yale University and the University of Southern California found that obese people had a more difficult time fighting off cravings for high-calorie foods, which could explain why it is difficult for obese people to lose weight.

The researchers showed pictures of high-calorie foods (including French fries and doughnuts) low-calorie foods (including tofu and salads) and non-foods to five obese and nine non-obese study participants.

When blood sugar levels were low in both obese and non-obese participants, the region of the brain associated with reward was activated, triggering a desire to eat high-calorie foods. Once the levels were brought back up to normal in the non-obese group, there was increased activity in the prefrontal cortex, the region of the brain involved in impulse control. The non-obese people were then less interested in the high-calorie foods.

This was not the case for obese participants. Not only was the desire for high-calorie foods more noticeable in their brain activity, but when their blood sugar levels were brought back up to normal, their brains continued to show a craving for high-calorie foods.

Copyright 2011 ABC News Radio

Wednesday
Jun222011

Could Eating Fake Fat Make You Gain Weight?

Stockbyte/Thinkstock(WEST LAFAYETTE, Ind.) -- Another diet myth bites the dust: products containing the calorie-less fake fat Olean, of fat-free potato chips fame, may make you gain weight, not lose it.

In a new study released Tuesday by Purdue University, researchers found that rats who were fed Olean-containing potato chips as part of a high-fat diet ate more overall and gained more weight than those who were fed a high-fat diet and regular, full-fat potato chips.

This counter-intuitive finding shakes the conventional wisdom that substituting lower calorie, lower fat foods for the full-fat versions will help reduce overall caloric intake and encourage weight loss.

"Fat substitutes can interfere with the body's ability to regulate what it eats, and that can result in overeating," said Susan Swithers, lead author and psychology professor at Purdue University.

But overeating may not be the only reason why fat substitutes make you pack on the pounds.  Researchers suspect that fake fats actually tamper with our body's ability to digest and metabolize food, making us more likely to retain weight from what we eat.

"Our bodies make predictions on what to prepare to digest based on taste and how food feels in our mouth," Swithers said.  When something tastes sweet or fatty, our body gears up to digest a high density of calories, stimulating the metabolism and triggering a chain of hormonal secretions to process the fat, calories, and nutrients."

"When we get cues that something is fatty, but no calories arrive -- like with fat substitutes -- our body gets confused," Swithers said.  "This confusion can make the body stop preparing to digest fatty food when it does come."

Olean is the brand name for Olestra, a calorie-less, fat-free fat-substitute discovered accidentally by Procter & Gamble in 1968.  Olestra was approved for use as a food additive in snack foods in 1996 and soon after became famous for its negative gastrointestinal side effects, including intense diarrhea and anal leakage.

Copyright 2011 ABC News Radio

Monday
Feb282011

Diet: Starving on Pregnancy Hormones?

Photo Courtesy - Getty Images(NEW HAVEN, Conn.) -- With one-third of Americans obese and many more overweight, the nation is desperate for a weight-loss miracle. But the return of the HCG diet -- a fad popular in the 1970s that combines daily injections of "human chorionic gonadotropin" and extreme caloric restriction -- has some weight-loss experts worried.

"We're so desperate to have good solutions for weight control that a lot of people with good common sense literally suspend it when it they confront weight-loss claims," Dr. David Katz, director of the Yale University Prevention Research Center, said. "This diet is appalling. It takes irresponsible diets to new heights."

HCG is a hormone first produced by the developing embryo and then the placenta during pregnancy to help nourish the womb. Because calories are rerouted from mother to fetus during pregnancy, HCG diet promoters say, injecting the hormone will help curb appetite and allow dieters to get through a day on the energy equivalent of a turkey sandwich.

"A 500-calorie-a-day diet is just plain dangerous," Katz said. "When you restrict calories to that level, there's a real risk for not providing your body with enough essential amino acids, so it scavenges itself. In some instances, it can cause the body to scavenge from critical places, like the heart."

The danger of very low-calorie diets has been well documented since their rise in popularity in the '70s. A 1981 study published in the American Journal of Clinical Nutrition described 17 people, all of whom were initially obese and had significant and rapid weight loss, who died suddenly of ventricular arrhythmia after a median five months of dieting.

The lowest recommended caloric intake per day is 1,200 calories for women and 1,500 for men, according to the National Institutes of Health. Restricting calories beyond those limits should only be done under doctor supervision because of the health risks.

Copyright 2011 ABC News Radio







ABC News Radio