August 19, 2014
By Harvey B. Simon M.D.
Harvard Medical School
"You are what you eat."
It’s a common bit of folk wisdom, but it doesn’t tell us what diet is best for health. Doctors have debated various programs ranging from low-fat, high-carb plans to high-fat, low-carb diets. So they haven't been much help, until recently. After more than 50 years of controversy, a clear winner is beginning to emerge. When it comes to health, the Mediterranean diet is best. It's high in complex carbohydrates and fiber but low in simple sugars. It includes moderate amounts of unsaturated fat, proteins and alcohol.
A Centuries-Old Diet
The traditional Mediterranean diet is centuries old. It has flourished in rural regions of Greece and parts of southern Italy and France. Here are its 10 characteristic features:
- An abundance of vegetables, fruits, beans, nuts, seeds and other plant foods
- An abundance of unrefined grains, such as whole-grain cereals and breads
- Olive oil as the major source of fat
- Moderate to large amounts of fish
- Fruit as the typical dessert, with sweets containing honey or sugar eaten several times a week
- Yogurt, cheese and other dairy products eaten daily in small to moderate amounts.
- Four or fewer eggs per week
- Moderate to large amount of poultry and small amounts of red meat
- A reliance on locally grown, fresh, minimally processed foods
- Moderate amounts of alcohol, usually wine with meals.
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A Tasty Mix of Benefits
The study of diet, heart disease and health dates back to the 1950s and the landmark Seven Countries Study started by Dr. Ancel Keys. It showed that regions with a low consumption of saturated fat, such as the Mediterranean countries, had a much lower incidence of coronary artery disease than regions with a high consumption of saturated fat, such as the Scandinavian countries. This study led to "the cholesterol hypothesis" which is now accepted as fact.
But current research has gone beyond fat to study the overall impact of the Mediterranean diet. Dozens of observational studies from Greece, Italy, France and other European countries have supported the Mediterranean diet. But the results of a randomized clinical trial announced last year provide clear proof of the diet's benefits.
The PREDIMED study included 7,447 people between the ages of 55 and 80. None of the subjects had heart disease when they joined the trial, but all of them had major cardiac risk factors. Scientists randomly assigned the volunteers to one of three diets:
- A Mediterranean diet supplemented with extra-virgin olive
- A Mediterranean diet supplemented with nuts
- A standard low-fat diet
Researchers tracked the subjects for about 5 years. When they tallied the results, the people who followed either of the Mediterranean plans had a nearly 30% lower risk of heart attack, stroke or death from cardiovascular disease.
Europe may seem a long way from Main Street. Most American studies don't refer to this type of diet as "Mediterranean." But they have very similar findings from a similar dietary pattern.
Two recent studies from Harvard have backed up the European ones. The first evaluated nearly 75,000 women who were free from heart disease when they signed up for the study. During 20 years of observation, the women who followed the Mediterranean-style diet most closely were 39% less likely to die from heart disease and stroke than women who followed the diet least closely.
In 2014, the second Harvard study reported on over 17,000 men and women. They already had heart disease when the study began. The results showed that the diet was linked to a reduced risk of death from both cardiovascular disease and cancer during nearly 8 years of follow up. And you don't have to worry if you don't fit the Harvard profile, since a study from Northern Manhattan reported similar results.
Protection from heart attack and stroke should be enough to convince you that real men should eat Mediterranean. But if you need extra motivation, consider the fact that the diet also appears to protect against:
- Weight gain and abdominal fat
- Alzheimer’s disease
- Parkinson’s disease
- Several cancers
That’s a tasty mix indeed.
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Making it Work for You
The Mediterranean diet is healthful, enjoyable and easy to adapt to American tastes and menus.
It avoids foods that are harmful, including saturated fat from animal sources, trans fat from partially hydrogenated vegetable oils, salty processed foods, and rapidly absorbed simple carbohydrates.
That's why it helps:
- Lower levels of LDL ("bad") cholesterol
- Increase levels of HDL ("good") cholesterol
- Lower levels of blood sugar and insulin
- Decrease vascular inflammation
- Lower blood pressure
- Shrink cholesterol-rich deposits in arteries
It's easy to follow. Here are some guidelines:
- Choose whole-grain products such as breads and cereals.
- Eat five or more servings of vegetables a day; count ½ cup of cooked or raw vegetables, 1 cup of raw leafy greens, or ½ cup of vegetable juice as 1 portion.
- Eat four or more servings of fruit a day; count ½ cup of fresh, frozen or canned fruits, ¼ cup of dried fruit, 1 medium-sized piece of fruit, or ½ cup of fruit juice as 1 portion.
- Eat at least 6 ounces of grain a day. Count 1 cup of dry cereal; ½ cup of cooked cereal, rice or pasta, or 1 slice of bread as the equivalent of one ounce. Whole grains should provide at least half of your grains; the more the better.
- Eat two or more servings of fish a week; count 4 ounces as 1 serving.
- Eat the equivalent of 5½ ounces of protein-rich foods a day. Count 1 ounce of cooked fish, ¼ cup of cooked beans or tofu, ½ ounce of nuts or seeds, 1 egg, or 1 ounce of cooked lean meat or poultry equivalent to 1 ounce.
- Eat 3 cups of non- or low-fat dairy products a day.
- If you choose to drink, limit yourself to 1 (for women) to 2 (for men) drinks a day; count 5 ounces of wine, 12 ounces of beer or 1½ ounces of liquor as 1 drink.
The Mediterranean diet may sound foreign and exotic, but these guidelines are based on the current recommendations of the Institute of Medicine and the U.S. Department of Agriculture.
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One Ingredient You Can't Leave Out
While an excellent diet is necessary for excellent health, it is not enough. Your good diet should be matched by good exercise. In fact, both are part of the traditional Mediterranean lifestyle. Just 30-40 minutes of moderate exercise (such as walking) will do the trick as long as you do it nearly every day.
Some 2,400 years ago, the Father of Medicine explained it all: "If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health."
Can it be a coincidence that Hippocrates was Greek?
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Harvey B. Simon, M.D., is an Associate Professor of Medicine at Harvard Medical School and a member of the Health Sciences Technology Faculty at Massachusetts Institute of Technology. He is the founding editor of the Harvard Men's Health Watch newsletter and author of six consumer health books, including The Harvard Medical School Guide to Men's Health (Simon and Schuster, 2002) and The No Sweat Exercise Plan, Lose Weight, Get Healthy and Live Longer (McGraw-Hill, 2006). Dr. Simon practices at the Massachusetts General Hospital; he received the London Prize for Excellence in Teaching from Harvard and MIT.