A meta-analysis of 45 studies found that it showed favorable effects on lipoprotein levels, endothelium vasodilatation, insulin resistance, metabolic syndrome, antioxidant capacity, myocardial and cardiovascular mortality, and cancer incidence in obese patients and in those with previous myocardial infarction.11

Commercial Diets With Evidence-Based Support

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Several commercial dietary programs have been studied and found effective for weight loss:

Jenny Craig: An analysis of data from 60,164 adults who enrolled in Jenny Craig’s Platinum Program over a one-year period found weight loss of 1.1+/-1.6% of initial body weight during the first four weeks of the program and 12.0+/-7.2% between 40 and 52 weeks.12 

A second study of the Jenny Craig Rewards Program, which includes “greater personalization of treatment, motivational interviewing, setting progressive behavior change goals, corporate partnership, and providing discounts based on length of participation,” found longer participant retention and greater weight loss.13

Weight Watchers has shown strong evidence of safety and efficacy. For example, a systematic review of major US commercial weight loss programs—including eDiets.com, Health Management Resources, Take Off Pounds Sensibly, OPTIFAST, and Weight Watchers—found that only Weight Watchers was supported by robust evidence.14 

A British study compared several commercial programs, including Weight Watchers, to weight reduction programs led by primary care practitioners. All the programs achieved significant weight loss, but at one year, only the Weight Watchers group had significantly greater weight loss than did the comparator group.15

The Atkins Diet: A randomized trial of 160 participants compared the Atkins diet (carbohydrate restriction), Zone (micronutrient balance), Weight Watchers (calorie restriction), or Ornish (fat restriction) to assess weight loss and heart disease risk reduction. 

The researchers found that “each popular diet modestly reduced body weight and several cardiac risk factors, although overall dietary adherence rates were low.”16 In that study, Atkins scored lowest on weight loss and second lowest on adherence/retention rates. 

However, a 12-month randomized trial of 311 overweight/obese nondiabetic premenopausal woman randomly assigned to follow the Atkins, Zone, LEARN, or Ornish diets found that those assigned to follow the Atkins diet lost more weight and experienced more favorable overall metabolic effects at 12 months than did those assigned to the other diets.17

Meal Replacement Approaches: Several diet programs, such as SlimFastTM employ bars or liquids as replacements for meals. According to the ACC/AHA Guideline, “the use of liquid and bar meal replacement is associated with increased weight loss at up to six months, in comparison to a balanced deficit diet utilizing only conventional food.”5 

A 2011 study of the SlimFast program in obese adolescents found that use of meal replacement “significantly improved short-term weight loss, compared with a conventional diet, but its continued use did not improve maintenance of lost weight.”18

Online Dietary Interventions and Mobile Apps

Recent evidence suggests that the Internet is “promising weight loss treatment modality”19 that may be equal in effectiveness to in-person modalities.20 Programs with superior outcomes “offer the greatest opportunities for engagement, including interactive, dynamic website features and synchronous counselor contact.”19 

A 2012 study of KiloCoachTM, an online weight reduction program, found that it was as effective as Weight Watchers in achieving and maintaining weight loss over two years.21

A study of 30 weight-loss mobile apps, available on iPhone and/or Android platforms, found that they “typically included only a minority of the behavioral strategies found in evidence-based weight loss interventions.” 

Missing were “behavioral strategies that help improve motivation, reduce stress, and assist with problem solving.”22 The authors suggested “inclusion of additional strategies” to make apps “more helpful to users who have motivational challenges.”22


During the season of New Year’s resolutions, health care providers might be in a position to offer suggestions or warnings regarding weight loss programs that patients might try. It is important to remain informed regarding evidence for or against commercial dietary approaches.