What’s the best diet to keep you healthy through the years or, better yet, reverse health problems caused by decades of poor eating habits? The debate seemed to be settled in February with a landmark study showing that the Mediterranean diet — which includes fat from olive oil, fish, and nuts, and a moderate amount of wine — led to 30 percent fewer heart disease deaths, strokes, and heart attacks than a low-fat diet in people over age 55 who hadn’t yet developed heart disease.
Nutrition researchers who had been extolling the virtues of “heart-healthy’’ monounsaturated fats and fish oil for decades felt vindicated. But those who had previously demonstrated that very low-fat diets with no vegetable oils or animal fats can help manage diabetes and reverse heart disease weren’t convinced. The control group in the Mediterranean diet study, which was supposed to follow a low-fat diet, didn’t actually adhere to the principles of low-fat eating, they said.
No one disputes the overlapping virtues of both diets: plentiful quantities of fruits, vegetables, legumes, and whole grains with virtually no red meat, sweets, or processed snack foods. But is it better for your heart if you sauté those vegetables in olive oil, or steam them? “The two diets have never been compared in head-to-head trials,’’ said Kathy McManus, director of nutrition at Brigham and Women’s Hospital.
In trying to determine which type of eating plan is best for you and will provide the most protection against heart disease and other ills, consider the following questions.
How much do you resemble the people who were studied?
In the February study that was published in the New England Journal of Medicine, researchers found that the Mediterranean diet worked pretty well to lower the likelihood of heart attacks and strokes in a group of nearly 7,500 Spaniards who didn’t have heart disease but were at increased risk: They were overweight and had type 2 diabetes or at least three other heart disease risk factors such as smoking, high cholesterol, and high blood pressure.
Very-low-fat diets, which usually limit fat to 10 to 20 percent of total calories, have largely been tested on populations who already have diseases that could shorten their life span. More than two decades ago, small trials demonstrated that a vegan diet combined with exercise, emotional support, and stress management techniques reduced artery plaque and heart attacks in those with established heart disease. Follow-up studies suggested that the lifestyle plan might keep type 2 diabetes and prostate cancer under control.
“An ounce of prevention equals a pound of cure,’’ said Dr. Dean Ornish, founder and president of the nonprofit Preventive Medicine Research Institute in Sausalito, Calif., who created the diet and lifestyle program. “If you’re just trying to prevent disease, the Mediterranean diet is fine, but if you’re trying to reverse it, you have to go further.’’
Study participants often have a difficult time making significant dietary changes and sticking with them over the long haul.
Ornish’s research included highly motivated patients who were worried about dying from a second heart attack, but even so, about 30 percent of participants quit his program within five years.
In the Mediterranean diet study, getting participants to give up burgers and fries for fish, beans, and quinoa wasn’t easy either, said Dr. Miguel Martínez-González, one of the study coauthors. “We had quarterly visits with participants where the dietitians negotiated small changes to be attained in the next three months,’’ he said. “There was flexibility.’’
What do you hope to accomplish from your eating plan?
If you’ve already been diagnosed with heart disease, you might want to try the Ornish plan for reversing disease. Many heart patients also lose significant amounts of weight when they make such an extreme overhaul.
“I’m not going back, and I really don’t miss the meat, chicken, or sweets,’’ said Michael Rubino, who lost about 40 pounds on the Ornish plan. He’s been on it since last June after he went into cardiac arrest at his Boston gym.
Katherine Tucker, a professor of nutritional epidemiology at Northeastern University in Boston, said it’s possible that the low-fat Ornish plan might be more beneficial for those with heart disease. “People who have had heart attacks might have a genetic predisposition to having more damaging effects on their arteries from higher fat diets,’’ she said, but more research is needed to confirm this.
She recommends following the Mediterranean diet for heart disease prevention, however, because it’s easier for most people to stick with permanently.
Researchers have also found health benefits such as reversal of hypertension from the Dietary Approaches to Stop Hypertension (DASH) diet. It includes about 20 to 35 percent of calories from fat — somewhat less than the 30 to 40 percent of calories allowed on the Mediterranean diet plan and more than what’s allowed on the Ornish plan. The DASH plan has the same emphasis on fruits, vegetables, and whole grains but limits sodium intake and alcohol and emphasizes potassium-rich foods such as bananas. It also includes plenty of animal protein such as lean beef, low-fat dairy, and chicken, so it might be easier for some people to follow.
What type of professional support will you get?
People who participate in clinical trials testing specific diets nearly always get help from dietitians and sometimes even get free food delivered — a far cry from the real world.
Ornish said that people who are most successful at adopting his plan long-term usually require 72 hours of training with an exercise physiologist and registered dietitian. Medicare now offers coverage for these educational sessions for heart disease patients, usually reimbursing about 80 percent of the $80 per hour cost.
The Mediterranean diet may take less time to learn, but still may require a few hours of counseling from a dietitian, said McManus. Medicare and many other insurance plans cover professional counseling four times a year for those with type 1 and type 2 diabetes. Those who are obese with a body mass index of 30 or greater can also get coverage under a mandate in the federal health law.
“It takes a while to adapt depending on a person’s baseline diet,’’ McManus said. “Someone may need to switch from butter to olive oil and move from an animal-based meal to a more plant-based one that includes very small amounts of chicken or lean meat.’’
How willing are you to make big changes?
Both the Ornish and Mediterranean diets require significant makeovers if you’re following a typical American-style diet, but the Mediterranean diet is likely closer to what you’re already eating now.
“I never feel like I’m depriving myself,’’ said Abby Sloane, 27, who switched to the Mediterranean diet five years ago and dropped 90 pounds, which she’s kept off. She said it wasn’t too difficult to switch from nachos and chips to whole grains and hummus after finding recipes on the website from the Boston-based nutrition education organization Oldways, where she now works.
“It’s not really a diet; it’s a lifestyle change,’’ Sloane said. “I didn’t want something that I tried for a few months. I wanted to change my life.’’
by deborah kotz | globe staff