MONDAY, Nov. 9 (HealthDay News) -- Both a high-fat, low-carbohydrate diet such as the popular Atkins program and a low-fat, high-carb diet appear to help people lose pounds over the course of a year.

But as for mood? Only the low-fat diets will result in long-term improvement in mood, according to a study in the Nov. 9 issue of Archives of Internal Medicine.

People on both diets consumed roughly the same number of calories.

"Both an energy-reduced, very low-carbohydrate, high-fat diet and a conventional high-carbohydrate, low-fat diet are equally effective for achieving weight loss in overweight and obese individuals," explained study author Grant D. Brinkworth, a research scientist with the food and nutritional sciences division of the Commonwealth Scientific and Industrial Research Organisation in Adelaide, Australia.

"Both dietary patterns also had similar effects on the cognitive domains assessed," which were working memory and speed of processing, Brinkworth added. "However, the conventional high-carbohydrate, low-fat weight-loss diet was shown to have more positive effects on mood compared to the very low-carbohydrate, high-fat diet."

Dr. Ewald Horvath, interim chairman of psychiatry at the University of Miami Miller School of Medicine, said the study was the first "to show both long-term weight loss and improved mood."

"This study looked at one factor, and prior studies haven't focused on psychological factors," Horvath said. "This is a great study focusing on something very important."

Other studies have found short-term improvements in mood in people who lose weight on different diets. And the new study also found such improvements over the first eight weeks of dieting.

But few studies have looked at long-term mood changes among people who lose weight.

Health organizations, such as the American Heart Association, tend to advocate higher-carb, low-fat diets. But many overweight and obese people are propelled toward the high-fat diets such as Atkins, "Livin' La Vida" and "Good Calories, Bad Calories," perhaps because of quick initial weight loss, Horvath said.

For the new study, 106 overweight and obese adults, who averaged 50 years old, were randomly assigned to one of two diets -- a low-calorie, low-carb, high-fat plan or a high-carb, low-fat diet -- for one year. Both diets restricted calories to about 1,433 to 1,672 a day.

A year later, average weight loss was about the same in each group: 30.2 pounds.

After the first eight weeks, participants in both groups showed mood improvements, but that lasted only in the low-fat group. After a year, the mood of those in the high-fat group returned to what it had been before they started dieting, the study found.

"The exact mechanism for the observed effects on mood still remains largely unknown," Brinkworth said. "However, if the mechanism for the return of mood toward more negative baseline levels following weight loss with a very low-carbohydrate diet is related to this diet being so far removed from normal dietary habits, then a very low-carbohydrate diet may be best recommended for individuals who habitually consume low amounts of carbohydrate foods in their diet."

More carbs can increase serotonin concentrations in the brain, whereas added fat and protein can reduce concentrations. Serotonin is a neurotransmitter involved in mood.

"Altered mood has been shown to influence interpersonal behavior and, therefore, the consumption of a very low-carbohydrate diet may have psychosocial consequences for interpersonal behavior and relationships," Brinkworth said. "I am not entirely clear as to the effects of mood on long-term weight loss; however a recent review article ... suggested that one of the factors that may pose risk for poor long-term weight maintenance may be 'eating in response to negative emotions and stress.'"

"Therefore, since negative mood may promote overeating, this suggests that consumption of a very low-carbohydrate diet over an even longer period beyond one year may have implications for maintaining dietary habits and weight loss maintenance," he added. "Further, longer-term studies would be required to confirm this."

More information

The American Dietetic Association has more on healthy eating  .

FRIDAY, Nov. 6 (HealthDay News) -- Getting enough sleep can help you make healthier food choices, researchers say.

The new study included 542 male motor freight workers, who often work long hours and have irregular shifts. The average age of the participants was 49, and 83 percent were white.

The researchers from the sleep medicine division at Harvard Medical School found that adequate sleep was a strong predictor of healthy food choices, while work experiences were not significant predictors. The findings suggest that adequate sleep mediates the effects of the workplace on healthy food choices.

"Sleep duration and sleep quality are contributing factors to increasing chronic disease trends, in that insufficient sleep duration and sleep disruption have been linked to weight gain, diabetes and early mortality in the long term," the study authors wrote. "Our findings suggest that sleep adequacy, by enhancing [healthy] dietary choices, is one means by which workplace factors may influence chronic disease risk."

The study was published online Nov. 4 in the American Journal of Public Health.

More information

The American Osteopathic Association offers sleep tips  .

SUNDAY, Oct. 25 (HealthDay News) -- To keep colds at bay during the chilliest months of the year, exercise just might be the key.

David Nieman, a representative of the American College of Sports Medicine, says that studies have shown that people who exercise at least 45 minutes four or more days a week take 25 to 50 percent less time off from work because of illness.

"This reduction in illness far exceeds anything a drug or pill can offer," Nieman said in a news release from the sports medicine group. "All it takes is a pair of walking shoes to help prevent becoming one of the thousands predicted to suffer from the common cold this winter."

But what if you're already under the weather? Should you try to get some exercise? Nieman suggests:

• If a cold is only in your head and has not reached your chest, feel free to exercise.
• Don't overexert yourself. That means no running: Just take a walk. Studies have not shown that moderate exercise is bad if you have a cold.
• If you have symptoms beyond the sniffles, stay in bed. This advice holds if a cold has traveled to your chest, if you have severe aches and pains and if you're running a fever. Swollen glands spell trouble, too.
• Take it slow when recovering from anything but a mild bout of illness. Take a couple of weeks off from exercise before you start workouts again.

Nieman has one more bit of advice: Exercise before you get your flu shot because research has shown that moderate-level physical activity will boost your immunity in the long run.

More information

The U.S. National Institute of Allergy and Infectious Diseases has more about preventing colds.

MONDAY, Aug. 24 (HealthDay News) -- Most American women should not consume more than 100 calories of added sugar a day, while men should limit their intake to no more than 150 calories, according to a new recommendation from the American Heart Association.

"Added sugar" refers to sugars added to foods during processing, during cooking or when a food is consumed.

The recommendation works out to about six teaspoons of added sugar a day for women and about nine teaspoons for men. In the United States, people take in more than 22 teaspoons of added sugar (355 calories) on average, each day, according to the 2001-2004 National Health and Nutrition Examination Survey.

Excess intake of added sugars has been linked to numerous health problems, including obesity, high blood pressure and other risk factors for heart disease and stroke. The Heart Association said that soft drinks and other sugar-sweetened beverages are the major source of added sugar in Americans' diets. Its new recommendations are in a scientific statement issued Aug. 24.

One 12-ounce can of regular soda contains about eight teaspoons of sugar and 130 calories, noted the statement's lead author, Rachel K. Johnson, associate provost and a professor of nutrition at the University of Vermont in Burlington.

"Sugar has no nutritional value other than to provide calories," Johnson said in a news release from the Heart Association. "Consuming foods and beverages with excessive amounts of added sugars displaces more nutritious foods and beverages for many people."

The statement, published in the Aug. 24 issue of Circulation, also recommends that added sugars should account for no more than half of a person's daily discretionary calorie allowance.

People should eat a diet rich in fruit, vegetables, low-fat dairy products, high-fiber whole grains, lean meat, poultry and fish, the association says.

More information

The American Academy of Family Physicians offers healthy eating advice  .