DEAR DOCTOR K: I want to go on a diet and am trying to decide between low-fat, low-carb and Mediterranean. What do you think?
DEAR READER: Your first two options — low-fat and low-carb — are too simple. There are “good” fats and “bad” fats, and “good” carbs and “bad” carbs. You don’t want a diet that is low in good fats or good carbs. You want a diet that is low in bad fats and bad carbs.
A good diet should provide plenty of choices and few restrictions. It should be as good for your heart, bones, brain and colon as for your waistline. And it should be something you can sustain for years.
— LOW-FAT. Fat contains nine calories per gram while carbohydrates contain four. Therefore, a low-fat diet might make it easier to keep your daily calorie count down. Calories, and the unhealthy weight gain they can trigger, are definitely something you want to control. But just controlling your calories doesn’t guarantee your diet is healthy. They have to be the right calories.
There are three problems with low-fat diets. The first is that you don’t take in enough good fats. The second is that low-fat diets tend to be less filling and flavorful than other diets, and this lessens their long-term appeal. It also means that the resulting hunger may cause you to take in more calories than you should.
Third, low-fat diets turn out to be high-carb diets. You substitute carbs for the fats you’ve chosen not to eat. Unfortunately, many people who put themselves on a low-fat diet consume not just more carbs but more bad carbs. These highly processed carbs, such as white bread and white rice, are rapidly digested, causing more hunger — and higher blood sugar levels. Instead, choose good carbs — whole-grain, fiber-rich carbs.
LOW-CARB. People on low-carb (high-protein and fat) diets do often consume fewer calories, resulting in weight loss. But most people cannot sustain a low-carb diet. If you choose a low-carb diet, select one that allows you to eat nutritious (but carb-rich) fruits and vegetables.
Which brings me to what I regard as the winner: the Mediterranean diet. I’ll bet that doesn’t surprise a regular reader of this column.
MEDITERRANEAN STYLE. These diets contain moderate amounts of healthy fats, most of them from olive and canola oils, fish and nuts. The carbs in this diet come from unrefined, fiber-rich whole-wheat and beans. Mediterranean diets are also rich in fruits and vegetables, nuts, seeds and fish, with only modest amounts of meat and cheese. The Mediterranean-style diet has been shown to reduce the risk of many diseases, including cardiovascular disease and diabetes, and of premature death.
If you find diets too restrictive, follow these principles of healthy eating. They can help you improve your health and lose weight along the way:
— Cut down on refined carbs.
— Eat more fruits, vegetables and whole grains.
— Increase plant oils and fish in your diet.
— Eat only moderate amounts of low-fat dairy products and nuts.
— Limit portion size and total calories.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.