America's obesity epidemic is arguably showing up more in the results of public companies, but not always in the ways that companies want. McDonald's sales are declining, and Coca Cola's latest results didn't give out too many smiles, either. Meanwhile, some "healthier" food options continue to gain: Chipotle Mexican Grill shares are up 15 percent this year, and General Mills recently paid $820 million for Annie's Homegrown. Still, for an investor who doesn't want to make a long-term bet that the average American will definitively give up their Coke and Big Mac, there are other ways to fight fat that can make the global population healthier, while making you wealthier. Investing in obesity stocks has become a Wall Street trend. While recent performance of some companies suggest the thesis is running ahead of the actual results, the demographic numbers are eye-opening.



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Some 84 million people in the U.S. struggle with obesity, a growing trend. In 2012, 35 percent of adults were obese, compared with only 14 percent in 1980, according to a National Health and Nutrition Survey. And estimates point to a larger girth in the future. Globally, more than 500 million people are obese, according to the World Health Organization. That number is slated to more than double by 2030.

"Diet and exercise aren't effective," said William Plovanic, medical technology equity research analyst at Canaccord Genuity.

In fact, given these round numbers, one place to start is medical devices designed to help people lose weight. In a recent report, Canaccord Genuity stated that obesity is the "next big thing in medical devices." The FDA is reviewing and expected to advance new technologies for obesity, since obesity costs to the health-care system are expected to nearly double by 2018. "The device market is in its early stages," Plovanic said. "New products and technologies will help drive traction."

Read MoreTesla's bet on winning the global lithium war Plovanic has a buy rating on the medical device company EnteroMedics, which develops neuroblockers to treat obesity. Hunger is controlled with a pace maker–like device that blocks signals from the stomach to the brain. However, the firm is still waiting for FDA approval on its medical device and hasn't banked any revenues yet. In 2015, EnteroMedics' revenues are expected to start flowing, Plovanic said. "There is a huge market opportunity."

Forget exercise—there's a pill for that

From the biotech arena, obesity drugs also hold promise. Canaccord Genuity biotech analyst Corey Davis highlighted Zafgen, which went public this year. Zafgen is developing a drug called Beloranib, which has logged fast weight-loss results, in part, by changing the way fat is converted into energy. Davis has a target price of $36 on the stock; it's $18 now. 2014 health-care ETF performance leaders

First Trust NYSE Arca Biotechnology ETF: 34.2 percent

PowerShares Dynamic Biotech and Genome: 28.7 percent

SPDR S&P Biotech: 24.6 percent

iShares Nasdaq Biotechnology: 22.8 percent

Market Vectors Biotech: 21.2 percent (Performance is year-to-date through Oct. 23, Source ETF.com)

Early players in the race to fight obesity with drugs, like Vivus and Arena Pharmaceuticals, have been disappointing, though. Vivus has plunged more than 60 percent this year, and Arena is down nearly 30 percent. Read MoreDrugmakers awakening to Ebola profit potential Among the reasons for the high hopes but lack of performance: Adoption has been slow, and only a few insurance companies pay for these weight-loss drugs, said Alan Carr, a senior analyst at Needham and Co. "The launches went poorly," Carr said. "And sales are slow. The companies may take another year to gain traction."



Weight-loss profits and losses