Diet firms try new tacks to lure weight-loss customers

For this year's weight-loss season, Nutrisystem Inc. is trying to capture resolution-making Americans with a plan that uses an algorithm to calculate the calories an individual needs and then sends them food from a menu personalized to their tastes. Weight Watchers International Inc. has a new two-week jump-start plan with a mobile application, while Medifast Inc. is adding store locations through franchising.

No matter what products they introduce, diet companies are facing two major obstacles: Growing competition from digital upstarts that give away their products, and the old problem that people typically fail to keep off the pounds and eventually quit dieting.

"You're going to need a coach and to have a support system that will make it last beyond the first week, first month, first quarter of 2014," George Blackburn, a professor of nutrition at Harvard Medical School, said. He estimated those types of diets don't work for three-quarters of people.

Many Americans are turning to free mobile diet and fitness applications, such as MyFitnessPal LLC, whose users can track exercise and calories from a database of more than 3 million foods for free.

Other free smartphone apps include Nutrino, where users can build a personalized menu, and My Diet Coach, which sends nutrition reminders and motivational photos. - Bloomberg News