Low-tech fitness, vitamin and weight-loss stocks are other avenues for investing.
Sean Naughton, a senior research analyst at Piper Jaffray, likes Life Time Fitness, which is up over 8 percent this year. The company provides full-service gyms, nutritional coaches and blood work to solve weight-loss problems. "It's also opening up new gyms," Naughton said, "and revenues are growing about 7 percent this year."
As for weight-loss stocks, Kurt Frederick, an analyst at Wedbush, likes Medifast, which is up more than 19 percent this year. It sells weight-loss foods, but Frederick said the direct selling arm has struggled lately. However, new products being rolled out mean "the long-term outlook is good," he said.
One heavyweight in the space, Weight Watchers International, is struggling. And it's on a financial diet: "It's cutting costs a lot," Frederick said, "but has fewer paying customers, so growth will be difficult."
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As the fortunes of the traditional weight-loss companies wane—Nestlé sold the bulk of its Jenny Craig weight-loss business last year to a private equity firm at a loss, according to analysts—Frederick sees a rise in vitamin retailers. That industry is growing faster than weight-loss companies because it also plugs into other trends, such as an aging population. "A lot of people try to lose weight on their own," he said.
Frederick has outperform ratings on both GNC Holdings and Vitamin Shoppe. GNC has had a rough year, and the stock took a big hit—it's down 32 percent. But the vitamin company, which also sells weight-loss and nutritional supplements, has a new CEO, and revenue, which was flat this year, will start growing again next year, Frederick said. Also, comparative store sales are strengthening, which the Wedbush analyst said was part of the thesis for his $46 price target on the stock.
Vitamin Shoppe, which is down more than 11 percent this year, sells hundreds of nutritional products through its 660 stores. Frederick is modeling double-digit revenue growth in 2015, and with its CEO announcing plans to retire, reports last week that the firms was considering a sale and speaking to investment bankers, the stock has been an active one. It rose 8 percent last week on the reports.