Remember the column, "Laughter is the Best Medicine?" Reader's Digest was on to something! A scientific study has just shown for the first time that laughter is linked to the healthy functioning of blood vessels. The study, conducted at the University of Maryland School of Medicine in Baltimore, showed that laugher causes the tissue that forms the inner lining of blood vessels (the endothelium) to expand and increase blood flow.

In the study, which was partially funded by the National Institutes of Health, participants watched either funny or stressful movies and had their blood-vessel activity measured. Average blood flow increased 22 percent during laughter and decreased 35 percent during mental stress. This study builds on research conducted in 2000, which suggested laughter may be good for the heart. Source: Alternative Health News Online

How often to eat can be almost as vexing to those trying to achieve a healthier weight as what to swallow. Are three regularly spaced meals daily the best recipe for fat-burning? Or five to six mini-meals?

The recent publication of "The Three Hour Diet" (HarperCollins) by fitness guru and bestselling exercise author Jorge Cruise is likely to help fuel the debate. Cruise contends that the timing of meals is as important as what's eaten. For successful weight loss, he insists, meals should be spaced three hours apart, with the last bite taken three hours before bedtime.

Despite more than 40 years of research into whether eating three large meals or multiple small meals is better, "no clear consensus has emerged," note Elizabeth J. Parks, assistant professor of human nutrition at the University of Minnesota, and Megan A. McCrory, research associate professor of nutrition and exercise science at Bastyr University in Kenmore, Wash., in a recent editorial published in the American Journal of Clinical Nutrition.

As they point out, something much more basic is at work: calories. Whether you eat three meals or six, weight loss ultimately comes down to "how much energy is consumed, as opposed to how often or how regularly one eats," the team concluded.

So whether you're thinking of feasting three times a day or noshing on multiple mini-meals, here's some advice based on the latest research:

Eat breakfast. Numerous studies point to the importance of breaking the overnight fast with food. Breakfast doesn't have to be eaten immediately upon rising, although there's evidence to suggest that consuming food within an hour or so of waking helps keep blood sugar levels even and insulin production steady and lowers hunger. Members of the National Weight Control Registry, a group of more than 3,000 people who have lost at least 30 pounds and kept it off for at least three years, report that eating breakfast is key to their efforts.

In February, a team of British researchers reported the effects of skipping breakfast on a small group of healthy, lean women. Participants first spent two weeks eating a breakfast cereal with 2 percent milk before 8 a.m. and then having a cookie between 10:30 and 11 a.m. daily. They then ate four additional meals spaced throughout the day. After a two-week break, participants started the day with a cookie at 10:30 to 11 a.m. and then had cereal and milk between noon and 1:30 p.m. They then had four more meals throughout the day.

Reporting in the American Journal of Clinical Nutrition, the researchers concluded that skipping breakfast resulted in greater consumption of calories, higher levels of total blood cholesterol and low-density lipoprotein (LDL) -- one of the most dangerous types of cholesterol -- and changes in insulin sensitivity that "could lead to weight gain if the observed higher energy intake was sustained."

Do a little math. Take the daily number of calories you're aiming for and divide by the number of meals you want to eat. (To estimate daily calories to maintain your current weight, multiply your body weight in pounds by 10. Then add about 20 to 40 percent more calories if you're sedentary; 40 to 60 percent more if you're active.) So if you aim for the average 2,000 calories daily recommended for most adults, you could have about 650 calories at each of three meals or 325 calories at six meals. "I know that people hate to do the math, but it's not that hard," McCrory notes. (To trim pounds, daily calories likely need to be in the 1,200 to 1,600 range.)

Mix it up. That means having a few ounces of lean protein with a serving of complex carbohydrates and a bit of healthy fat. It's this mixture that helps keep blood sugar and insulin levels steady. A few smart choices: Banana with peanut butter; soup with beans and a whole-grain cracker; low-fat or nonfat yogurt with fruit.

Pay attention to portions. That's a key strategy whether you eat three regular-sized meals daily or five to six mini-meals. One of the biggest concerns about mini-meals is that beginning to eat each meal "is like letting a tiger out of a cage," notes Parks. "The more meals that you allow in your day, the more opportunity you have to overeat."

Engage in regular eating. British researchers led by Hamid R. Farshchi of the Centre for Integrated Systems at the University of Nottingham reported in January that obese women who ate regular meals at roughly the same time every day consumed fewer total calories, metabolized calories better, lowered blood cholesterol levels and showed improvement in insulin production compared with when they ate irregular meals. *

By Sally Squires
Tuesday, April 12, 2005; Page HE01
© 2005 The Washington Post Company