Diet programs work, but the brand doesn't matter

When it comes to diet programs, brand names don’t make much difference, according to a new review.

Low-carb or low-fat diets resulted in the most weight loss, but despite a difference of a few pounds between groups, all the programs in the study were about equally effective, said lead author Bradley C. Johnston.

“The weight loss differences between branded diet programs were small with likely little importance to those seeking to lose weight,” he told Reuters Health by email.

Johnston, of the Hospital for Sick Children Research Institute in Toronto and McMaster University in Hamilton, Ontario, said any diet program should include exercise and behavioral support.

The analysis included 49 randomized controlled trials that tested 11 popular branded diets for at least three months. All of the participants were overweight or obese, and they all had daily nutrient or calorie targets. Some had exercise goals as well.

The low-carb diets, like Atkins, South Beach and Zone, require that no more than 40 percent of daily calories come from carbohydrates and another 30 percent come from protein.

The low-fat diets, including the Ornish and Rosemary Conley diets, specify that less than 20 percent of calories come from fat, and 60 percent come from carbohydrates.

Johnston and his team also included trials of moderate macronutrient diets, like Biggest Loser, Jenny Craig, Volumetrics, Nutrisystem and Weight Watchers, which also require around 60 percent of calories from carbohydrates but allow more from fat and less from protein than the low-fat diets studied.

Compared to no diet at all, each of the diets produced more weight loss, but low-fat and low-carb were most successful, according to results in JAMA.

At the six-month point, people on low-carb diets had lost an average of 19 pounds, which dropped to 16 pounds at one year. Low-fat dieters lost an average of more than 17 pounds by six months, which also dropped to 16 pounds by one year.

Moderate macronutrient dieters lost an average of 12.5 pounds after one year.

The different diet brands within each category didn’t make much difference, the authors write. For example, among the low-carb diets, the Atkins diet resulted in about four more pounds of weight loss than the Zone diet at the six-month point.

“I think in general when people follow a specific plan and have a support system and guidelines that pull them away from their normal everyday behavior, I would expect to see weight loss,” said Lindsay Malone, a registered dietitian at the Cleveland Clinic who was not part of the new review.

While weight loss appeared slightly greater with low-carb versus low-fat diets, “with either one you’re making a lot of significant changes, eliminating junk food and junk calories,” Malone told Reuters Health by phone.

She and her colleagues typically don’t endorse specific diet brands. Instead, they sit down with patients and talk about their lifestyle, what has worked for them in the past, and recommend certain characteristics of diets individually, she said.

Though the moderate macronutrient diets in the review resulted in slightly less weight loss than others, they may still be the best choice for some people, she said.

“Moderate macronutrient provides the greatest variety so is easiest for some people,” Malone said. “If they are feeding a family or eating on the go a lot, maybe that is a little more doable for them.”

Though the brands themselves didn’t differ meaningfully, there are still advantages to branded diet programs, Johnston said.

“Branded diets are likely more effective than general dietary guidelines because they typically involve a comprehensive program including behavioral support and physical activity,” he said. “Some also include prepared foods, recipes and meal ideas.”

Health professionals can help assess which diet program the patient is most likely to stick to and achieve lasting weight loss, as well as a diet’s potential impact on other health measures like cholesterol and blood pressure, Johnston said.

“We know that you can achieve weight loss with more than one type of diet,” Malone said. “The diet that really should be presented or offered to people is the one they’re going to stick to.”