Photo: Michael Fusco

Why calorie restriction? Brian M. Delaney, co-author of "The Longevity Diet" and president of the Calorie Restriction Society says, "the evidence in virtually every species studied indicates that calorie restriction slows the aging process, and extends 'youth span.' Studies in humans that actually measure mortality may never be done, since they would take over a century to complete, but shorter-term studies in humans indicate that 'biomarkers' of age and rate of aging shift in the same way they do in the calorie-restricted animals." An added bonus? He says he feels better, all his health markers have "moved dramatically in positive directions" and "generally, I feel much better now than before I started calorie restriction." In an interview with That's Fit, he describes an average day of eating, what he does in social settings and what he does to avoid pigging out.

That's Fit: What is a typical day's worth of meals and number of calories for you?

Brian M. Delaney: I eat a hearty breakfast -- usually a large bowl of whole grain cereal with non-fat yogurt and soymilk (or some other, less fatty "legume milk" of my own making, using for example navy beans), [served with] lots of blueberries and usually some other fruit.

I skip lunch, mainly because it saves time! But I also skip lunch because I love eating a large breakfast ("Breakfast like a king..."), and, for social reasons, often need to eat a normal-sized dinner, so I can't be on calorie restriction unless I skip lunch.

Dinners are usually a very large salad with lots of colorful vegetables, some kind of thick lentil or other legume soup (pinto beans, navy beans, etc.). I usually eat a bit of dark chocolate for desert, and often drink red wine.

I follow a vegetarian diet at home; when I'm invited out, I gladly eat what I'm served!

At the moment my daily caloric intake is around 2,000. (I could go lower, but I don't want to be that scrawny, for reasons of pure vanity.) [Reporter's Note: According to USDA recommendations, a moderately active adult male should consume, 2,200 to 2,800 calories; Delaney says he's active, so he may even fall in the 2,400 to 3,000 calorie range.]

That's Fit: Do you ever "fall off the wagon" or take a day off because you feel like you're missing out?

Delaney: With calorie restriction, there isn't really a "wagon" in the normal sense. Studies with lab animals show that what matters is that long-term energy-intake is restricted, when averaged out over the course of two- or three-day periods. For example, studies show that animals stuffing their faces one day, then fasting the next, experience the "calorie restriction effect" about as much as animals restricting by 30 percent every day.

So, sure, if I'm served a huge meal at a friend's, I'll eat it, then eat less the next day. Binging for a whole week, then fasting, or eating very, very little the next week, is not something I would recommend, however.

The "Longevity Diet" isn't about lists of good foods and evil foods, so the only thing I'm missing out on is the frequent experience of eating to excess, an experience which, I admit, can be very pleasurable! But there are plenty of other cravings, ones that have nothing to do with food, that I give in to on a regular basis.

That's Fit: Who should restrict their calories? Is there a good age to begin doing so?

Delaney: People are radically, delightfully varied in their passions and life's goals. Although I've written a book about calorie restriction and am president of the Calorie Restriction Society, I am, oddly enough, reluctant to say anyone should restrict their calories. That said, there are some people who might find it an excellent idea. But let me begin with those who probably should not restrict their calories more than slightly: anyone who is pregnant or trying to get pregnant, anyone not fully grown (aside from those who are truly obese), anyone with a history of eating disorders and anyone who hasn't discussed the idea with a knowledgeable healthcare professional.

Those who might want to consider following a plan like "The Longevity Diet" are basically those who want to live a long, healthy life. Following the diet is easier than most people realize, but that doesn't mean it's for everyone. But if you're interested in living an unusually long, healthy life, with radically reduced risks of developing type II diabetes and cardiovascular disease and greatly reduced risks of developing most types of cancer and premature senility, then calorie restriction is worth considering.