A calorie-restriction diet sounds about as basic as they come. It’s no secret that we could all benefit from cutting a few calories. But this isn’t your mother’s persnickety stab at weight loss (although shedding pounds is a happy side effect). Restricting calories means deliberately and carefully feeding your body fewer calories than it needs—without skipping any nutrients—and research shows it is the closest we may ever come to the Fountain of Youth.
For decades, scientists have known that restricting calories puts the brakes on aging in everything from worms to mice. But, last year, University of Wisconsin researchers inched closer to the holy grail (human proof) when they found that rhesus monkeys on a calorie-restriction diet were half as likely to get cancer, heart disease and diabetes—the trifecta of human aging—than their calorie-munching peers. And less disease equals longevity. Indeed, those monkeys eating and aging “normally” died at three times the rate of those nibbling on 30 percent fewer calories.
“There is no question that calorie-restriction dieting increases the life span of any species,” says Eric Ravussin, Ph.D., director of the Nutrition Obesity Research Center at Louisiana State University. But the potential for longevity in people is still not clear. However, not everyone is waiting for the final verdict. Lisa Walford, 55, coauthor of The Longevity Diet (Da Capo Lifelong Books), has followed a calorie-restriction diet for more than 20 years. Introduced to the idea by her father, the late Roy Walford, M.D., one of the first scientists to map the diet’s health benefits, she attributes her physical and mental vitality to yoga and consuming fewer calories. “I fall asleep easily; I sleep deeply; and my energy levels are stable throughout the day,” she says. “There is also a psychological shift that happens on the diet. You might call it an emotional calming.”
The three steps to success
Calorie-restriction dieting is about minimizing calories and maximizing nutrients. The first step is to determine the number of calories you need to maintain your body’s “set point,” which is the weight your body naturally gravitates toward if you make no effort to lose or gain weight. Then you aim to eat fewer calories, which is where the weight loss enters.
In animal studies, the biggest boon—a 50-percent jump in life span—surfaces when calories are sliced by 40 percent, but the most people can reasonably expect to cut is 25 percent, says Ravussin. Researchers have tried to cut people’s calories by 30 percent, but volunteers find the diet unsustainable.
So, what does a 25-percent restriction look like? If you can consume 2,000 calories a day and maintain your “set point” weight, your new goal should be 1,500 calories. That’s roughly Lisa Walford’s daily calorie count. At 4 feet, 10 inches tall, she is a diminutive 80 pounds. (Her set point is 95.) A typical day’s menu may include a bowl of lentil soup for lunch, and a heaping salad full of colorful vegetables and topped with a hard-boiled egg and tofu for dinner. Walford knows she’s not scoring any points with nutritionists by admitting she skips breakfast, but it works for her. “There is no one-size-fits-all formula for a calorie-restriction diet, which is both its beast and its blessing,” she says.
Notice Walford’s menu doesn’t include any nutrient-void, low-calorie treats, such as pretzels. That’s because the second step of a calorie-restriction diet is an unwavering dedication to stellar nutrition. Fresh fruits and vegetables are the diet’s center stone. Small servings of nutrient-dense, high-energy foods, such as nuts, lean protein and avocado, fill in the gaps with healthy fats and protein.
The third step’s a doozie: sticking to it. “People who successfully cut 25 percent need to have a perfect knowledge of optimal nutrition and a high capacity for detail,” says Ravussin. Most important, calorie-restriction dieters must sacrifice short-term pleasures (a thick slice of chocolate cake) for longterm gains (healthier aging).