Tom Fitch, a busy salesman, is calling from his mobile "office" somewhere along Highway 101 – hands-free, of course. He's rushing to meet clients, make his pitch over dinner, then move on to the next stop.

But if you think the 55-year-old Elk Grove resident is too busy to even remember what he had for breakfast, well, think again. He writes down every meal and snack, every single morsel of sustenance that parts his lips, in a food diary.

"I had a breakfast shake, 200 calories," he says. "And I've had a couple of granola bars on the road, 150 (calories) apiece. So, by the time I'll have dinner with clients tonight, I can have a reasonable meal without worrying."

In the six months since Fitch started a weight-loss program – documenting each bite along the way – he has lost 65 pounds. He's down to 215 and plans to keep it off, which is why he is vigilant about keeping tabs on his intake.

"Writing things down keeps it in your mind," Fitch says.

He was one of 1,700 participants in a recent Kaiser Permanente Center for Health Resources study looking at just how effective diet diaries are at helping people lose weight.

Results, to be published in August in the American Journal of Preventive Medicine, show that subjects who keep detailed diaries of food consumed lost twice as much weight (average of 13 pounds in six months) than those who did not record consumption.

"It seems that the simple act of writing down what you eat encourages people to consume fewer calories," lead Kaiser researcher Jack Hollis says.

That shouldn't come as a surprise, according to Dr. Sheri Pruitt, a clinical psychologist and director of Kaiser Permanente's Behavioral Science Integration program.

"By writing down or tracking behavior," Pruitt says, "it makes us more aware of it. That's true in many things, including food consumption.

"We're trying to increase people's awareness of their eating habits. If you know you're going to have the write that down, then you're more thoughtful about what you eat. You think, 'Am I actually going to eat that chocolate? No, because then I'm going to have to write it down.' "

Or, on the flip side, a person could choose to eat and not tell.

Judith Stern, professor of nutrition and internal medicine at UC Davis, says some patients simply can't keep up the vigilance of a food diary. But if they do, it can be beneficial.

"It's an individual thing," she says. "You might not be willing to do it even though it's worked for you in the past because it's a pain. But I've also had people say to me, 'I'd rather not eat it if I have to write it down.' "

Pruitt, a consultant to Kaiser's weight-management program, says their patients routinely do food journaling. She acknowledges that there is some initial reluctance.

"Most of the time, when people think of writing down every single thing, every little calorie, it can kind of be overwhelming," Pruitt says. "If you frame it that way to patients, they'll think that's too much to do. That's punishing even to think about it.

"You tell them to make it simple and something that works for them. It could be on a calendar or even a Post-It note. You can make it … elaborate or not."

Fitch says he's low-tech and prefers the old-fashioned between-the-covers diary. But he says others in his weight-loss group use online food forms that automatically calculate calories consumed.

"It can be a hassle," Fitch says. "But your attitude is, 'How successful do I want to be? Is it worth a little hassle to know how much and how often you eat?' "

That's the most surprising thing patients discover after using a diary, Pruitt says.

"We underestimate the amount of calories we consume in a day," she says. "The thought process is probably something like this: 'Oh, you know, 100 calories, what's the big deal? Then another 50 calories here or there.' But it accumulates over the day. If you're making dinner and tasting the spaghetti, you need to write that down, too. You may have had half a cup of sauce.

"The diary teaches people to be thoughtful, aware and reflect."

It's taught Fitch not to "cheat himself" by conveniently forgetting to log calories.

"I've lost 65 pounds and absolutely do not want to put it back on," he says. "So I've got to write down everything I eat. Every last thing."

Call The Bee's Sam McManis, (916) 321-1145.