THE BEST DIETS FOR 2015

DIET #1: DETOX (FOOD) DELIVERED- DL REVAMP: If the thought of detoxing fills you with dread, this could be the program to win you over. The latest offering from DeliverLean, a Florida-based health-food delivery service, the five-day detox ($625) consists of vegan whole foods, delivered by FedEx. Developed

with chefs–health coaches Alina Zhukovskaya and Mary Graham, it's designed to cleanse, rev up your metabolism, and set you on a path to healthful eating. "In today's toxic environment, our organs need the extra support of good food to get them working at optimum levels," says Zhukovskaya. "The body is very smart—give it the right nutrition and it will get to the weight it wants to be."

 The expert opinion:"I like the idea of a detox, as we know from science that there are real addictions to food, sugar, and fat," says Thomas Campbell, a physician and the executive director of the T. Colin Campbell Center for Nutrition Studies in Ithaca, New York. "But this is more of a jump-start. What happens after those five days is what is really important."

DIET #2: CHEAT YOURSELF SLIM

THE 3-1-2-1 DIET: A new twist on intermittent dieting comes from this book by Dolvett Quince, a trainer on NBC's The Biggest Loser. Quince's plan dictates that you eat "clean" for three days, have a cheat day, eat "clean" for another two, have a cheat day, and so on, with the prospect of dropping 10 pounds if you follow its well-balanced, calorie-controlled diet for 21 days. Motivation results from the fact that nothing is off-limits, and by indulging on regular cheat days (bacon, pancakes, and tequila are all on the okay list) you are speeding up weight loss, he says. "By systematically decreasing, then increasing calories, your body responds by keeping your metabolic rate higher than if you'd kept your calories low," Quince claims. "This is not about yo-yo dieting but balance." 

The expert opinion: "We should all have days or meals that are special occasions and guilt-free," says Lisa Sasson, an associate professor of nutrition and food studies at New York University. "It teaches us that there's no such thing as forbidden foods, and eating foods we love is all part of a healthy lifestyle."

DIET #3: SHARED SUCCESS

THE GIRLFRIENDS DIET: Written by the editors of Good Housekeeping, this book proposes that women who diet together experience greater weight loss success than those who go it alone, as studies have shown. The four-week meal plan is based on Mediterranean fare—there are recipes for tasty dishes like Greek chicken and grilled swordfish kebabs, as well as cocktails and chocolate cake. And while there's an initial limit of 1,400 to 1,600 calories per day, the point is to get you to adopt this style of eating permanently. The diet encourages women to create or join weight loss groups in order to support one another. "Mediterranean cuisine is considered the healthiest in the world," says health journalist and co-author Debora Yost. "This is a lifestyle, not a diet. You eat food you enjoy, get a handle on portion size, and benefit from the support of friends." 

The expert opinion: "I like that it doesn't exclude any food groups, and it's a move toward eating a whole-food diet, as it's heavy on fruit and vegetables but still allows a little meat," Sasson says. "And the collaborative element is encouraging because if you look historically at this way of eating, it's very social and supportive," she adds.