HEALTH Study shows benefits of low-cal diet

Calorie restrictors had lower blood pressure, insulin and glucose levels.
ST. LOUIS POST-DISPATCH
ST. LOUIS -- Eat less, live longer. Or at least healthier.
That's the message from the first long-term study of "caloric restriction" in people. Previous studies in animals fed ultra-low-calorie diets showed that cutting calories could increase the life span of rats, mice, fish, worms, fruit flies and other insects.
Now, Washington University researchers have studied a group of low-cal, high-nutrition dieters and found that carefully controlled calorie consumption results in "profound and sustained" beneficial effects on all the major factors contributing to the risk of heart disease.
The study will appear this week in the on-line version of the Proceedings of the National Academy of Sciences.
The researchers, led by Luigi Fontana, a nutrition researcher at Washington University and the Istituto Superiore di Sanita in Rome, Italy, compared 18 people on high-nutrition calorie-restricted diets with 18 average people of the same age. (Average in the United States has come to mean slightly overweight, due to an epidemic of obesity, Fontana said.)
Study participants
The study group, including three people from St. Louis, are members of the Caloric Restriction Optimal Nutrition Society. The dieters have followed low-cal regimes for three to 15 years, averaging six years.
All of the volunteers kept a log of what they ate for a week. The control group -- those people who ate a typical American diet -- consumed as few as 1,976 calories each day and as many as 3,537 calories in a day.
The calorie-restricted group's intake ranged from 1,112 calories per day to 1,958 calories each day. There is no cut-off calorie count for restriction, Fontana said. Each person is different and designs meals based on individual energy requirements. The dieters generally shun processed foods containing trans fatty acids and refined sugar and starch.
Benjamin "Nick" Colby, 72, of Irvine, Calif., started restricting his calorie consumption 10 years ago. The trim anthropology professor aims to eat 1,400 to 1,500 calories per day. That's a level at which he neither loses nor gains weight, Colby said.
Colby admits enjoying food. He tucks into salads, skips the bread, munches on vegetables and fruit -- berries are favorites -- and gets his 60 grams to 70 grams of protein each day from yogurt, whey, beans and a small amount of meat.
Calorie distribution
As a group, the restrictors got 26 percent of calories from protein, 28 percent from fat and 46 percent from complex carbohydrates. The typical American diet comprises 18 percent of calories from protein, 32 percent from fat and 50 percent from carbohydrates.
As expected, the dieters were leaner than the non-dieters -- the restricted group sported a body mass index (BMI) of 19.6 with just under 7 percent body fat while the controls weighed in with a BMI of 25.9 and more than 22 percent body fat. People with a body mass index of 18.5 to 24.9 are considered normal weight for their height.
The calorie cutters' blood pressure was lower than their nonrestricted counterparts' -- 100/60 for the restrictors versus 129/79 for the control group. New blood pressure guidelines released last year would classify the control group as "prehypertensive." That means they could be at increased risk for heart attacks and stroke. The level was previously considered within the normal range for blood pressure.
Fasting levels of insulin and glucose -- measures of diabetes -- total cholesterol and low-density lipoprotein cholesterol (the so-called "bad cholesterol), triglycerides, and an inflammation indicator called C-reactive protein were all considerably lower in the calorie-restricted group. Only high-density lipoprotein cholesterol ("good cholesterol) went up in the caloric restriction group.
Quick results
Medical records from 12 people in the calorie-restriction group showed that they started out in much the same boat as the people in the control group. They started with body mass indexes of 24.5 -- approaching chubby.
It didn't take long to see results from the restricted calorie diets. The dieters' blood pressure dropped from an average of 132/80 at the start of the regimen to 112/69 a year later, finally dropping to 97/59 at the time of the study. Cholesterol and other measures of heart health took nose-dives into optimal territory as well.