WEDNESDAY, July 16 (HealthDay News) -- New research shows that Mediterranean and low-carb diets are just as good and just as safe as the low-fat diet often prescribed by doctors, a revelation that should give people more choices in eating well.

"We can't rely on 'one diet fits all,' " said Iris Shai, an epidemiology researcher at Ben-Gurion University of the Negev in Beer-Sheva, Israel. "This suggests several diet strategies, and that we should be tailoring them."

Shai completed the study, which was published in the July 17 issue of the New England Journal of Medicine, while a Fulbright fellow at the Harvard School of Public Health and Channing Laboratory in Boston.

For this trial, 322 "moderately obese" men and women (but mostly men) were randomized to one of three diets: low-fat, restricted calorie; Mediterranean, restricted calorie; or low-carb, non-restricted-calorie.

The Mediterranean diet had the most amounts of dietary fiber and also included lots of fruits and vegetables. All three regimens had similar calorie counts.

Over the next two years, an astounding 84.6 percent of participants stayed on their diets.

Mean weight loss for the low-fat group was 2.9 kilograms (4.8 pounds), 4.4 kg (9.7 pounds) for the Mediterranean group and 4.7 kg (10.3 pounds) for the low-carb group.

For the 272 participants who stayed on their diets, the mean weight loss was 3.3 kg (7.3 pounds), 4.6 kg (10.1 pounds) and 5.5 kg (12.1 pounds), respectively.

The low-carb regimen reduced the ratio of total cholesterol to HDL "good" cholesterol by 20 percent, while the low-fat one lowered the ratio by 12 percent.

The best change in lipids was seen in the low-carb group, with a 20 percent increase in HDL cholesterol and a 14 percent decrease in triglycerides.

The Mediterranean diet produced the most favorable changes in blood glucose and insulin levels among the 36 participants with diabetes. In this group of patients, the low-fat diet increased fasting glucose levels.

According to the study authors, a low-carbohydrate, non-restricted-calorie diet may be optimal for those who will not follow a restricted-calorie dietary regimen. The increasing improvement in levels of some biomarkers up to the 24-month point, despite the achievement of maximum weight loss by six months, suggests that a diet with a healthful composition has benefits beyond weight reduction.

"The three diet strategies were beneficial for two years for all the biomarkers, but some of them were more specifically better than others," Shai said. "The good news is that you can consider and choose one strategy, but, once you choose one, you should stick with it."

"You have to look at each individual," added Lisa Harper Mallonee, a registered dietitian and an assistant professor of dental hygiene at the Texas A&M Health Science Center Baylor College of Dentistry. "Practice moderation and creating individual, healthy diets."

More information

The American Heart Association has more on the Mediterranean diet  .

MONDAY, July 14 (HealthDay News) -- Men and women with early-stage Alzheimer's disease who were more physically fit also had larger brains compared to their counterparts in less stellar shape.

The findings, though preliminary, may indicate that staying physically fit could slow the brain atrophy (shrinkage) associated with Alzheimer's disease. Or they may indicate that some common underlying process affects both brain atrophy and cardiorespiratory fitness.

"This is a valid, reliable comparison, [but] it's cross-sectional, it provides only a snapshot of fitness as it relates to brain volume," said Dr. Gary Kennedy, director of geriatric psychiatry at Montefiore Medical Center in New York City. "We can't say if increased fitness increases brain volume. Animal models show this is possible. This sets the stage for an interventional study."

The findings are published in the July 15 issue of Neurology.

In older adults without dementia, staying in good physical shape may help offset the changes in the brain, such as cognitive decline, associated with normal aging.

But experts have not yet clearly defined whether or not physical activity has an effect on those with Alzheimer's.

"We're interested in how exercise impacts the Alzheimer's disease process. There's a lot of data in normal older adults that exercising and fitness may have a beneficial effect on brain health, but there's not a lot on Alzheimer's in terms of studies to draw on to inform our recommendations for exercise and fitness," said study author Dr. Jeffrey Burns, director of the Alzheimer's and Memory Program at the University of Kansas School of Medicine in Kansas City. "We're interested in better defining that relationship."

For this study, 57 people with early-stage Alzheimer's and 64 people without dementia, all aged 60 and over, underwent standard fitness tests and MRI brain scans.

"We used an objective, gold-standard measure of fitness which hadn't been assessed in Alzheimer's patients yet, cardiorespiratory fitness, or VO2 peak, where we basically measure how much work someone is capable of doing," Burns explained.

Participants walked on a treadmill while their oxygen consumption was measured. "At their peak, how much oxygen they're consuming is a measure of how physically fit they are," Burns said.

MRI scans measured brain atrophy.

The VO2 peak was slightly lower in people with Alzheimer's compared to controls. And individuals with Alzheimer's who were less physically fit had quadruple the amount of brain shrinkage compared to normal older adults.

"The people with higher fitness levels had larger brains, and there was a strong correlation between the two," Burns explained. "We're limited because of the study design, but it could suggest that maintaining fitness may have a beneficial effect on the Alzheimer's disease process."

"We didn't find fitness to be associated clearly with cognitive performance, but that may be, because we need to study more people or the cognitive performance measures may not be sensitive enough," he added.

The study pointed to three possible explanations for the relationship: cardiorespiratory fitness affects brain atrophy related to Alzheimer's disease; the Alzheimer's disease process affects fitness; or some other, as-yet-unknown factor underlies both Alzheimer's-related brain atrophy and physical fitness.

"We're designing a study where we try to establish the cause and effect," Burns said. "Can we use exercise to enhance fitness in Alzheimer's disease and, by doing that, will it affect disease progression?"

More information

The Alzheimer's Association's Maintain Your Brain   program has more on how lifestyle factors affect your risk for dementia.

SUNDAY, July 13 (HealthDay News) -- Even though it's summertime, children shouldn't be allowed to take a vacation from healthy eating habits, advises Dr. Sarah Armstrong, a pediatrician at Duke University Medical Center.

"Routines go haywire, and with nothing to do after a few days in the pool, kids head straight for the refrigerator or snack bar, because they think they're hungry, when they're actually just bored," Armstrong said in a university news release.

Add in things like regular servings of ice cream to beat the heat, hot dogs at the ball park, and funnel cake at the fair, and you have a summer-long binge of bad eating that can lead to weight gain.

Armstrong offered parents a number of ways to prevent their children from packing on excess pounds this summer.

Make sure kids get enough sleep. Research shows that late nights and sleeping in are known risk factors for weight gain. "When kids stay up late, they are more likely to watch TV and snack on dense, low-nutrient foods," Armstrong said.

In addition, a shorter night's sleep limits the body's production of leptin, a hormone that promotes satiety. Lower levels of leptin mean children wake up feeling more hungry and are quicker to grab high-carbohydrate, calorie-rich foods.

When children wake up, encourage them to eat healthy breakfasts that include things such as fruit smoothies, high fiber cereal or a peanut butter and jelly sandwich on whole wheat bread.

Take a holiday from fast foods. Instead of going to a burger joint, pack a picnic with healthy foods such as turkey sandwiches and salads and go to the park or beach. Armstrong said it's important to "incorporate protein in every meal. It releases insulin at a slower rate, and that keeps your blood sugars -- and your energy level -- constant throughout the day."

Parents should check out the menu at their child's summer camp. If the meals and snacks aren't acceptable, pack your child a healthy lunch that includes things such as lean lunch meats, raw vegetables and whole wheat crackers.

During the summer, parents also need to limit their children's consumption of sweets and make sure kids are active.

More information

The Nemours Foundation has more about children and healthy eating  .

TUESDAY, June 3 (HealthDay News) -- Boys and girls develop eating disorders for different reasons, so prevention strategies may need to vary by gender, according to a new report.

"Frequent dieting and trying to look like persons in the media were independent predictors of binge eating in females of all ages. In males, negative comments about weight by fathers was predictive of starting to binge at least weekly," wrote the authors, whose findings were published in the June issue of Archives of Pediatrics & Adolescent Medicine.

Prevention strategies, they said, should address those specific causes. For example, campaigns aimed at females should focus on media literacy and decreasing their susceptibility to media images; for males, efforts should focus on how to be more resilient to negative comments about weight.

In analyzing seven years of data on more than 12,500 children, the researchers found 10.3 percent of the girls and 3 percent of the boys started to binge eat or purge (vomit or use laxatives to control weight) at least once a week. Purging (5.3 percent) was slightly more common than binge eating (4.3 percent) in girls, while boys were almost three times as likely to binge eat than purge (2.1 percent versus 0.8 percent). Only a small proportion of boys and girls had both disorders.

The children were between age 9 and 15 at the start of the study in 1996.

While girls under age 14 whose mothers had a history eating disorders were almost three times as likely than other children to start purging at least once a week, "maternal history of an eating disorder was unrelated to risk of starting to binge eat or purge in older adolescent females," wrote the authors, who were led by Alison E. Field, of the Children's Hospital Boston and Harvard Medical School.

More information

The U.S. National Institute of Mental Health has more about eating disorders.