Weight loss programs and diets are big business with $2.5 billion spent on these services in 2014. This is not surprising since 63% of adults have attempted to lose weight at some point. The largest three programs are Weight Watchers, Nutrisystem and Jenny Craig. How do the various programs stack up?
One review looked at 141 different programs. They divided programs into very low-calorie diets (VLCD), self-directed diets and leading market-share programs (LMS). End-points were the amount of weight lost over the short-term (<12 months) and long-term (12+ months). Selected diets were compared with controlled education. Costs of the programs studied varied between zero and $682 per month. The review did not evaluate physical activity, behavioral and social support, medication or supplement use. The average age of people in the studies was 37–57 years old and the subjects were predominantly women. VLCD diets included were Health Maintenance Resources, Medi-fast and Opti-fast. Self-directed diets were Atkins, Biggest Loser, eDiets, LoseIT and Slimfast. LMS diets were Jenny Craig, Weight Watchers and Nutrisystem.
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“Weight Watchers was the most cost-effective diet while Jenny Craig had the greatest sustained weight loss. Nutrisystem was good at short-term weight loss.”
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Results are summarized in the table. Due to heterogeneity of the studies, it is difficult to compare the diets and only generalizations can be made. Weight Watchers was the most cost-effective diet while Jenny Craig had the greatest sustained weight loss. The VLCD were superior to other programs in the short term. Nutrisystem, grouped as a leading market share diet in this study, was good at short-term weight loss as well. No trials were continued to evaluate long-term effects. VLCD had triple the risk of gallstones compared to low-calorie diets. Results of the self-directed diets were mixed.
These findings show that many programs are helpful in various settings and different programs have different short- and long-term outcomes. The authors conclude that Weight Watchers and Jenny Craig are the two best diets studied.
