While it might be true that a calorie from fat is the same as a calorie from protein or carbohydrate, Cheskin said, certain weight-loss techniques seem to work better than others. In his experience, the most successful diet is high-protein and low-carb and involves meal replacement, such as using ready-made, portion-controlled dinners or protein shakes for lunch.
"I have noticed that people who are on high-protein, low-carb diets have a better time adhering to that diet," he said. "They're less hungry, for example."
The study had other drawbacks. For instance, only about a third of people actually adhered to their diet. And participants gained some of their weight back in the second year. While the weight gain was slow, the trend could suggest that participants would be likely to gain back some of their weight even if they had continued treatment, said an accompanying editorial in the journal.
Weight-loss experts agree that motivation, encouragement and counseling can make a difference as to whether a person sticks with a diet. Study participants took part in group and individual counseling sessions, recorded what they ate in a daily food diary and used a Web-based program that encouraged them to meet their goals.
"It matters more that you are motivated and adhere to it," said Cheskin. "It's not that diets don't work, but diets don't work if you don't adhere to them."
Ralph Loglisci of Baltimore can attest to that. A lifelong dieter, he had tried them all: motivational tapes, self-help books, Overeaters Anonymous, Weight Watchers and even gimmicky color-coded menus popularized by the 1980s fitness guru Richard Simmons. Loglisci would lose a few pounds, only to gain them right back.
In 2003, he was 32 years old, weighed 383 pounds and couldn't go for a walk in his neighborhood without his back aching.
"I was one accident away from becoming one of those stories about people stuck in bed and needing to be taken out with a forklift," he said. "This was the fear in my head - it was horrible."
Loglisci sought help at the Hopkins Weight Management Center, which he says changed his outlook on food, dieting and health. He received behavior therapy and learned why he relied on food for comfort. He also received nutrition and medical advice and tips for controlling portion sizes, especially during the first few months. In nine months, he lost 185 pounds.
He learned that no matter what he ate, when he reduced his calories, he lost weight.
