TUESDAY, July 8 (HealthDay News) -- Keeping tabs on what you eat with a food diary can double your weight loss, a new study shows.

While the idea of food diaries has been around a long time, this latest research offers more proof they help you shed more poundage, said study co-author Dr. Victor J. Stevens, a senior investigator at Kaiser Permanente Center for Health Research, in Portland, Ore.

"It's not fun to write down what you eat; it just works," he said.

In the study, which is in the August issue of the American Journal of Preventive Medicine, they followed almost 1,700 men and women who were either overweight or obese. The average weight was 212 pounds. The participants attended 20 weekly group meetings and were encouraged to eat about 500 fewer calories a day, to engage in moderate intensity physical activity 30 minutes or more a day, and to follow the low-fat, low-sodium DASH dietary plan, which emphasizes fruits, vegetables and low-fat dairy foods.

Participants were asked to record daily food intake and their exercise minutes.

After 20 weeks, the total average loss was about 13 pounds, Stevens said. But the food record habit predicted success.

"The more food records they kept, the more they lost," he said. "Those who kept no food records lost about 9 pounds, and those who kept six or more per week lost about 18 pounds. That's a whopping difference."

What's the magic of a food diary? "It makes you accountable to yourself," Stevens said. "They handed in the food diaries, and we took a quick look." Any chance they were fiction? Stevens doesn't think so. "They also got on the scale every week at the meeting. And you can't fake that."

Writing down your intake yields clues about where the extra calories are coming from, Stevens explained, and participants said it got easier with time: "The more I got into it, the easier it became to keep track of what I ate every day," Frank Bitzer, 64, a retired project manager for the computer industry who lost 26 pounds, told the study leaders.

More information

To learn more about a food diary to analyze eating habits, visit the American Academy of Family Physicians  .

MONDAY, July 7 (HealthDay News) -- If 156 million adults in the United States took better care of themselves, the average American would live 1.3 years longer, and the number of heart attacks would fall by 63 percent.

That's the conclusion of a joint study released Monday that combined the resources of the American Heart Association, the American Diabetes Association and the American Cancer Society.

"Prevention makes a difference," said study co-author Dr. Rose Marie Robertson, chief science officer of the American Heart Association. "You can live longer, maybe substantially longer, and you can have a much healthier life."

Even a more realistic scenario -- assuming, among other things, that just 20 percent of obese Americans lost weight -- would lead to major improvements in the country's overall health, researchers found.

There's a hitch: The health gains are entirely hypothetical. The study is an exercise designed to measure scenarios in which millions of Americans stopped doing things that are bad for them.

One scenario examined what would happen if the 78 percent of Americans aged 20-80 with risk factors that threaten their health didn't have those risk factors anymore.

Some smoke. Others are heavy, suffer from high cholesterol or high blood pressure, don't take aspirin when their heart attack risk is high, or have other risk factors they don't control through a healthy lifestyle or medication.

The researchers assumed that all those Americans -- 156 million of them -- managed to stop smoking, lose weight, and control other risk factors. Then they used a statistical model to predict what would happen.

Under this scenario, the number of heart attacks would fall by nearly two-thirds, and strokes would decline by almost at third, the researchers found.

The average life span of all Americans, meanwhile, would grow by 1.3 years. That may not sound like a lot, but it's an average number and could be much higher for younger people, Robertson said.

"You really prevent serious things," she said. "If you prevent those, then that person is healthier, so they're able to engage in the things they like doing. They live to see their daughter get married or get their kids through graduation, all the things that are stolen away."

The study looked at another scenario, considered "more feasible," in which smaller numbers of people started taking better care of themselves. Among other things, 20 percent of obese people would lose enough weight to stop being clinically obese, and 30 percent of smokers would quit.

Under that scenario, the number of heart attacks would fall by 36 percent and strokes by 20 percent.

The findings were expected to be published in both the July 29 issue of the journal Circulation and the August issue of Diabetes Care.

In another study released Monday, Norwegian researchers report that short bursts of intense exercise appear to do a better job of reducing metabolic syndrome -- linked to heart problems -- than longer, less vigorous exercise.

The intense bouts of exercise weren't exhausting, though, and didn't require participants to push their hearts to their top levels of endurance, said study co-author Ulrik Wisloff, a researcher with the Norwegian University of Science and Technology in Trondheim, Norway. The study will be published in the July 22 issue of Circulation.

More information

Learn about heart-healthy habits from the American Heart Association  .

MONDAY, July 7 (HealthDay News) -- High intake of the omega-3 fatty acids in oily fish and vegetable cooking oils appear to help prevent heart attacks, while the omega-6 fatty acids in vegetables and nuts help keep blood pressure low, two international research teams report.

A study in Costa Rica found that high intake of omega-3 fatty acids reduced the risk of heart attack by 59 percent, said a report published in the July 8 online issue of Circulation.

In the Costa Rican study, "we compared those subjects who had heart attacks with those who did not have heart attacks," said study author Hannia Campos, a senior lecturer in nutrition at the Harvard School of Public Health. They had participants fill out food questionnaires and also analyzed body fat samples to determine levels of alpha-linolenic acid, a major omega-3 fatty acid.

A number of other studies have shown that high intake of omega-3 fatty acids is associated with lower risk of death from cardiovascular disease. This is the first study to look at its association with heart attack risk, Campos said.

"We found that the relationship is not completely linear," she said. "It plateaued after a certain level of intake. After that, higher levels do not mean increased protection."

The protective level turned out to be surprising low -- the amount in two teaspoons of soybean oil or canola oil, half a teaspoon of flaxseed oil or six to 10 walnut halves.

That protective effect could be detected, because the people in the Costa Rican study have a low level of omega-3 fatty acids in their diet, Campos said. "Their overall intake of fish is very low, much lower than in the United States, and the fish they eat are tropical, which are not as fatty as cold-water species," she said.

The high blood pressure study, reported in the July 8 online issue of Hypertension, looked at 4,680 men and women aged 40 to 59 from China, Japan, the United States and the United Kingdom. It found a significant relationship between intake of linoleic acid, an omega-6 fatty acid found in vegetables, and lower blood pressure.

The report is the latest in a series of studies designed to describe all the factors contributing to high blood pressure, said Dr. Jeremiah Stamler, a professor of preventive medicine emeritus at Northwestern Feinberg School of Medicine.

"For diet and serum cholesterol, most of the answers came in the 1960s," Stamler said. "The data on diet and blood pressure have come much more slowly."

Previous reports have shown that higher intake of calcium, magnesium and phosphorus are associated with lower blood pressure, Stamler said. Iron from vegetables -- but not meat -- also is associated with lower blood pressure, he said. "An array of macro- and micronutrients influence blood pressure in a variety of ways," Stamler said.

The latest study indicates that raising linoleic acid intake by 9 grams a day reduces systolic blood pressure (the higher of the 120/80 reading) by about 1.4 points, and diastolic pressure by about 1 point. That small reduction can have a large effect in a big population, the researchers said, with a 2-point reduction reducing coronary heart disease by 4 percent.

"The message of this study is to eat more fruit and more vegetables, more beans, less red meat and less fats," Stamler said. "Fats should be mainly selected to be unsaturated. Vegetable oils should be used but in moderation."

More information

A guide to omega-3 and omega-6 fatty acids is offered by the Vegan Society  .

SATURDAY, July 5 (HealthDay News) -- Your diet isn't all that healthy, and you haven't been to the gym since who knows when. You can't shed those pesky 20 extra pounds, but what's the use, you may ask -- after all, you're well into middle age.

To all that whining, Dr. Dana King would say: "It's not too late. If you make [healthy] changes now, it has a tremendous impact." Particularly on your heart. Even in middle age.

King, a professor of family medicine at the Medical University of South Carolina, is one of several researchers who have proven in recent years that it's never too late to get healthy -- and that adopting better habits even in midlife translates to less disease and a longer life.

King led a recent study that evaluated the cardiovascular effects of adopting healthier habits in middle age -- what he calls the "turning back the clock study."

And surprise! It works. What's more, you don't have to be fanatical, but the more healthy habits you adopt, not surprisingly, the healthier you become.

King and his colleagues evaluated almost 16,000 men and women who were between the ages of 45 and 64 when the Atherosclerosis Risk in Communities Study began. The researchers looked specifically at four heart-healthy habits: eating at least five servings of fruits and vegetables a day; exercising at least 2.5 hours a week; keeping a healthy weight; and not smoking.

During four years of follow-up, the researchers found that those who adopted the four healthy habits were 40 percent less likely to die and 35 percent less likely to suffer heart problems than those who did not adopt the beneficial habits. The findings were published in The American Journal of Medicine.

Stephanie Chiuve, a research associate at Harvard School of Public Health, and her colleagues led a similar study that included almost 43,000 middle-aged and older American men who were part of the Health Professionals Follow-up Study. The goal: to see if a healthy lifestyle is linked with a lower risk of heart disease, even among those who take high blood pressure medication or cholesterol medication.

The researchers looked at basically the same collection of healthy habits that King evaluated in his study, with some additions. "We looked at whether the diet was rich in not only fruits and vegetables but also whole grains, fish, chicken and other poultry and unsaturated fats -- like vegetable oils and nuts," Chiuve said. They also looked at whether participants smoked; got exercise for 3.5 hours a week at a moderate pace; consumed alcohol moderately; and kept a healthy body weight.

All were free of chronic heart disease in 1986, when the study began, and the men were ages 40 to 75.

Like King's team, Chiuve's team found that healthy habits make a big difference. Men who adopted healthy habits during the study period, from 1986 to 2002, had a lower risk of heart disease compared to men who didn't change their overall number of healthy habits.

"For each additional habit you added, the benefit increased," Chiuve said. Men who adopted one healthy habit had a 54 percent lower risk of heart disease, for instance, while those who embraced four had a 78 percent reduction in risk, she said.

"For the men who followed all five, they had an 87 percent lower risk of heart disease than the men who followed none," Chiuve said. The study was published in the journal Circulation.

While the study included only men, Chiuve believes the findings would also apply to women.

More information

To learn more about adopting a healthier lifestyle, visit the U.S. Department of Agriculture.