As a long-term investor, one of the strategies I use is to identify major trends, and then invest in the companies that are best positioned to profit from these trends. As an individual investor, you have something that institutions and hedge funds don't have: time. With all the pressure to beat the market annually, quarterly, or even monthly, the big boys can't afford to build a position in something that moves slowly.

So while there are plenty of these trends out there -- aging of the baby boomers, impact of emerging markets, and the ever popular cloud computing -- here's a trend that's near and dear to everyone's heart (and waistline): obesity. Studies show that Americans are getting more and more overweight, with major concerns about the health consequences of this growing (no pun intended) trend.

So how do you profit from this?
Well you could look at the obvious choices -- services that focus on weight loss like Weight Watchers (NYSE: WTW), Nutrisystem (Nasdaq: NTRI), or even Nestle, owner of Jenny Craig. Other companies to take a long look at are the drug makers fighting cholesterol or heart disease such as Pfizer (NYSE: PFE), Merck (NYSE: MRK), or AstraZeneca (NYSE: AZN). But what about other complications -- maybe those that are further from the forefront of investors' minds? One frequent obesity complication is sleep apnea and ResMed (NYSE: RMD) is at the forefront of treatment of the disorder.

ResMed makes its living selling Continuous Positive Airway Pressure (CPAP) devices, which are nasal interfaces or full masks that deliver a steady flow of air through the nose to keep the upper airway open. This prevents obstruction of the airway which causes sleep apnea to occur. Studies have shown that there are almost certainly links between obesity and sleep apnea. So if you believe that America is going to continue to struggle with obesity in the future, investing in the companies that treat sleep apnea is one way to potentially profit.

With all that said, does ResMed make a sensible investment choice?

A quick diversion
About three to four years ago, I invested in a company called Aspect Medical Systems, which since has been acquired by Covidien (NYSE: COV). Aspect sold machines that monitor the consciousness of patients under anesthesia during surgery. I thought this was a great idea and happily bought the company when it was beaten down near its 52-week lows. The problem with Aspect was that it was essentially a one product company, and when an article in the New England Journal of Medicine questioned the effectiveness of their product in early 2008, the stock was absolutely crushed.

So, I definitely see parallels between Aspect and ResMed. Don't get me wrong: ResMed is a bigger, more established company than Aspect ever was. And there are certainly many positives about ResMed's management effectiveness and financial performance. But I am concerned that ResMed essentially has only one product. Their website or filings indicate dozens of products, but the reality is that almost all of them do the same thing, or work in conjunction with each other.

So what does this mean?
Often investors, myself certainly included, tend to focus on the stock fundamentals when looking at a company. On the surface, this certainly makes sense as I'm looking to buy a stock, right? But to jump right into an analysis of P/E ratios, enterprise value to free cash flow, and growth rates before taking a long hard look at the business of the company is not only not Foolish, it's silly. And I'm just too concerned with the narrow focus of this company to invest in it.

ResMed could continue to prosper as sleep apnea becomes more commonly diagnosed and treated, as management anticipates, making oodles of money for shareholders. But I'd rather not take the risk that a better mousetrap won't come along making this product, in effect, obsolete. After all, who wants to wear a mask to sleep every night? If a new technology or treatment came about, how loyal will ResMed's customers remain? While I won't say that ResMed will eventually underperform the market, I'm not willing to buy it right now.

But I could certainly be wrong about this. I'm often wrong – it's one of my charms. But before I even think about wanting to beat the market, I think more about not losing money -- that's another one of my charms.

If you want to profit from obesity, I'd suggest sticking with the more traditional obesity treating companies above. While you may not be original, you're likely to be safer. Disagree with me? Leave me a comment below, and add ResMed to your watchlist for further Foolish coverage and performance tracking.

Fool contributor Stephen J. Marini does not own shares of any of the companies mentioned above. Covidien, Pfizer, and Weight Watchers International are Motley Fool Inside Value recommendations. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.