Could eating breakfast stave off depression? A study entitled "Breakfast and Mental Health," appearing in a recent issue of the International Journal of Food Science and Nutrition, found that a group of people in southern Wales who ate breakfast regularly were "significantly less stressed, less depressed and had lower emotional stress" than another group for whom breakfast was a sometime thing.

But don't trade in your Prozac for a cereal bowl or cancel your next appointment with the therapist just yet.

The unanswered question in the study, says James Fleet, director of the graduate program in nutrition at the University of North Carolina at Greensboro, is whether eating breakfast is the "cause of a better mental state or one of the things that people in a better mental state do." He comments that nothing in the study, funded with the help of cereal maker Kellogg's, "suggests that if you switch from not eating breakfast to eating breakfast, you'll get a sunnier disposition."

That's Fleet the scientist. Then there's Fleet the man, who says that without breakfast, "I poop out before lunchtime comes around. I get crabby and grumpy." So does his 2-year-old son, Ben. In fact, Fleet says, "almost every kid I've ever met gets crabby and grumpy if they don't eat some time reasonably early in the morning."

Okay, crabby and grumpy isn't the same as depressed and emotionally strung out, but clearly there's a mind-meal connection here. The evidence is particularly strong for children.

Research conducted by Harvard scientists in Baltimore and Philadelphia documented last year that children who participate in free school breakfast programs show improvements in standardized measures of academic and psychosocial success. Just four months after the breakfast program began, the students who ate the meals most frequently were "significantly more attentive in the classroom, earned higher grades in math, and had significantly fewer behavioral and emotional problems," according to Harvard scientist J. Michael Murphy. That translated into decreased tardiness and absenteeism along with less hyperactivity, depression and anxiety.

Parents whose children get adequate breakfasts at home also report that a morning meal improves their sons' and daughters' days. David Schardt, associate nutritionist at the Center for Science in the Public Interest (CSPI), says that if his three children have breakfast before they leave the house in the morning, "they do better in school, better throughout the day." They also eat better, he reports, because they don't snack between meals on foods that aren't as nutritious as what he serves at home: pancakes, waffles dipped into microwave-melted peanut butter, cereal, or scrambled eggs mixed with cheese (a favorite of 8-year-old Camille's).

Jeanne Goldberg, an associate professor of nutrition at Tufts University's School of Nutrition Science and Policy, points out that along with being an opportunity to feed nutritious foods to children, breakfast is a good time for families to connect. When her children were growing up, she says, her husband often attended business meetings in the evenings, so "he went out of his way to make sure" the family would sit together before rushing off in the morning.

However, "the problem is that a lot of kids aren't hungry when they get out of bed in the morning," she said, in part because school schedules often require that they "get out of bed at ungodly hours. Their digestive systems aren't talking to them yet.

"I just hung up with my daughter, a third grade teacher," Goldberg said during a phone interview. "The kids get to her classroom at 7:50. There needs to be more flexibility in schools for snacking. I understand that some schools don't allow snacks in the morning" but, she maintains, "some adaptability" is called for in those schools where the rules are too rigid.

CSPI's Schardt says his own children are among those who aren't always hungry before school. "Occasionally, they don't want" breakfast, he notes, "and you can't force kids to eat. We suggest that they take something with them as they walk to the bus. Sometimes Dennis [one of Schardt's two 10-year-old sons] will take an apple."

Fleet, too, says young Ben isn't always hungry when he gets out of bed. On those days, "we let him wake up a little bit" first, the nutrition researcher says, "maybe offer him some juice to start."

Should grown-ups go to the same trouble for themselves? Will having breakfast make them perform better at their daily tasks? "The research isn't as convincing for adults," Schardt says, but eating a good morning meal makes "intuitive sense."

There's a psychological effect from eating a satisfying breakfast. It starts you off on the right foot by making "you less tempted by foods that you might encounter" throughout the morning and the rest of the day. "And let's face it," Schardt says, "these days you're likely to encounter food everywhere"-- newsstands, vending machines, kiosks. And "it's not usually fruit," he points out. "More often it's huge muffins or doughnuts or pastry."

Goldberg notes that it's often quicker to serve yourself a nutritious breakfast than to buy a morning meal. "It takes longer to sit in your car with the motor idling at the doughnut shop drive-through than it does to take a bowl and a spoon, some cereal and some milk out of the fridge."

Goldberg, like Schardt, makes the point that if you start off the morning nutritiously, you'll be more inclined to eat healthfully throughout the day. "When people do one thing in a health-related way," she comments, "it starts to generalize. If you have pastry and coffee at 10, there's a tendency to say, 'Oh, the hell with it. I'll start right again tomorrow.' "

The same is true about breakfast and weight-loss efforts, and for that there is some supporting research. In a Vanderbilt University study published several years ago, 16 moderately obese, breakfast- skipping women were assigned to either a diet that included breakfast or one that didn't. The two meal plans provided the same number of calories; lunch and dinner were smaller for the breakfast eaters. The result: The women whose diets did not include breakfast lost an average of 13 pounds after 12 weeks; the breakfasting dieters lost an average of 17 pounds each. Eating breakfast appeared to reduce fat intake overall as well as minimize impulsive snacking throughout the day.

Earlier investigations suggested that breakfast eaters generally have higher nutrient intakes than others, with fewer calories from fat and a higher fiber intake as well. Goldberg isn't surprised. "You can glom on as much fat as you want," she says, "but there are really lots of traditional breakfasts in America that are nutrient-dense and low in fat"-- for instance, orange juice, oatmeal with fruit, "a piece of toast if you can afford the calories" and a glass of skim milk. The point, she says, is to make sure breakfast includes a starch, a calcium-rich food and fruit. An egg a few times a week is also fine, she points out--particularly because "eggs are nutrient-dense foods."

There's also "nothing wrong," she says, with a piece of leftover pizza. There's starch in the crust, calcium in the cheese and some vitamins A and C in the tomato sauce. Of course, whether to heat it up first or eat it straight from the refrigerator is your call.