Health and fitness is big business in the U.S., and companies who take advantage of that trend have started to become big winners for investors. Healthy foods, health clubs, and weight-loss programs have all been growing over the past decade and show no signs of stopping. 

In 2017, National Beverage Corp. (NASDAQ:FIZZ), NutriSystem Inc. (NASDAQ:NTRI), and Weight Watchers International, Inc. (NASDAQ:WW) have all risen sharply, and with market trends at their backs, they look to have bright futures. 

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Flavored water is the hit of 2017

I have to admit that I'm one of the people who helped drive National Beverage's revenue 20% higher, to $194.6 million in the most recent quarter, and helped double net income to $24.3 million. In particular, LaCroix is the fastest growing sparkling water brand, according to industry data, and high prices on health products are driving strong operating margins of 18.2% last quarter. 

National Beverage has essentially filled the role in the health market that Pepsi or Coca-Cola filled in the fast-food or soda market. It's a well-known brand that has, in many ways, replaced these everyday sugary drinks for consumers. And with the health trend only gaining steam, I think the stock has a bright future. 

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The weight loss fad pays dividends

NutriSystem and Weight Watchers are also surging on the market, primarily because they're gaining a lot of traction in their businesses. Nutrisystem's 2016 revenue jumped 18% versus a year ago, to $545.5 million, and diluted income per share jumped 34% to $1.19. 

Weight Watchers' 2016 revenue was up a more modest 1.3% to $949.1 million, but net income more than doubled to $67.6 million, and earnings per share hit $1.03. 

The number of customers for both companies are growing as the interest in a healthy lifestyle increases. And as they adapt and innovate new products, NutriSystem and Weight Watchers are set up to continue riding the health trend. 

The health craze will continue

In the last decade, there's been a big move by consumers to healthier eating and fitness habits. There's been the growth of healthier grocery stores like Whole Foods and the decline of fast food in favor of concepts like Chipotle and Panera Bread. Even fitness clubs like Lifetime Fitness and yoga brands like Lululemon have been able to ride this wave over a long period of time. 

Right now, the market loves the growth being experienced in weight loss and flavored water, and that's why National Beverage, Nutrisystem, and Weight Watchers are three of the best-performing stocks on the market in 2017. And if growth continues, their stocks may not be done moving higher. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.