by Dr Woodson Merrell: After seeing results in his patients, a once skeptical doctor is now a convert…

In my 25 years of medical training and practice in Manhattan, I’ve seen a wide range of diets come and go. Virtually none of them work. Of course, they may work for a few weeks or months, but my experience follows the national statistics that 90% of dieters regain their weight within two years of weight loss. The ones who have been successful are those who have made a permanent commitment to altering their eating habits and continuing to be active physically. A major problem is that the dedication it takes to stay on a diet, especially for those significantly overweight, is usually too much for most people. So the weight-loss gurus are always looking for a diet that requires little or no self-discipline.

Diets that drastically reduce caloric intake leave most people feeling too physically and emotionally deprived to continue. Also, the body is often quick to recognize caloric deprivation and adjusts by lowering the metabolic rate, thus sabotaging the effect of a lower caloric intake. I saw this when I was a consultant in a hospital weight-loss center that specialized in liquid diets. I was astonished at the number of people on 600-to-800-calorie diets whose weight loss seemed to stall after just a few weeks. Even worse, when you come off such a diet, the metabolism often remains at that lower level, making weight gain inevitable.

For most of my professional career, I adhered to the generally recognized dictum of weight management. I advised my patients to count their calories and follow a low-fat diet. So when low-carbohydrate diets experienced a resurgence in the mid-’90s, I dismissed them as another fad. But a funny thing began to happen. Many of the people who went on the modern Zone or Atkins diets lost weight, didn’t feel deprived, and were more successful in the long term.

Then I sat down with a cardiologist who not only espoused the Atkins diet but also had been on it himself and lost 40 lbs. over five months. He argued that the insulin-lowering effect of the diet was essential for allowing the body to burn fat more effectively. He also contended that reducing insulin levels could help prevent many diet- and weight-related diseases, including high cholesterol, hypertension and diabetes. Atkins is a cardiologist too, but he is selling books. This physician, with no vested interest, made it clearer to me that carbohydrates are often the culprit. Certainly the majority of my overweight patients are carbohydrate junkies.

I tried the low-carbohydrate diets on a few patients for whom nothing else had worked. To my surprise, they did well. I chose the more cautious Zone and Heller systems, with moderate-to-low fat intake, though I noticed that the patients who were experimenting with the Atkins system of high saturated fat and ultra-low carbohydrates seemed to lose weight even faster.

So I have become a convert. Carbohydrates in the amount we commonly consume them (particularly sugar and other refined carbos) are often prime saboteurs of our weight. What’s more, cutting back on them–especially on wheat–seems to produce improvements in energy, mood and sleep for many patients. It is hard to do–our culture is carbo- and wheat-driven. But of all the diets I’ve seen over the past few decades, the moderate-fat, lower-carbohydrate ones are the most successful. They stress not how much food you eat but what kinds. Calorie counting is not as important as carbo counting. They are not so much diets as a permanent change to a more balanced eating pattern.

I still have a difficult time recommending an Atkins-style, high-saturated-fat diet to my patients. Though the diet does provide a quick weight loss and is very satiating, I am concerned about its possible effects on people with serious heart, liver or kidney disease and cancer. As long as you are healthy, a high-fat diet is usually fine for a while. But after about a month, you should go off it. That’s the problem. When people begin to go off the strictest form of the diet, they have to be extremely careful as they increase the amount of carbos and dramatically cut back on fats. For most people, this is too much of a metabolic swing, and weight regain is all too common. The more moderate diets of Sears and the Hellers–cutting carbohydrates by about one-third and eating moderate amounts of fat, preferably monosaturated ones like olive oil–are more gentle to the system.

So we now have a new set of tools that can help reduce food cravings, lose weight, and often provide a better sense of well-being. But remember, amid all the talk about carbos and fats, that all responsible diets, low carbo or not, recommend a minimum of five helpings of vegetables and fruits a day. And there is not a diet in the world that is a substitute for that good old-fashioned metabolic jump starter called exercise.