That was Global Megatrend No. 1 as identified by Motley Fool Global Gains Advisor Bill Mann -- and he suggested that you own it for good reason. Capital is flowing worldwide like never before, and the current credit crunch will be just a blip when one considers the emerging purchasing power of consumers in places such as China, India, and Brazil.

That's not to downplay the significance of current events, but rather, to observe that the global influence of the U.S. economy is diminishing. Capitalize by picking up shares of strong global banking brands such as Citigroup (NYSE: C) (as money manager Ron Muhlenkamp advised during his recent investing seminar) or Goldman Sachs (NYSE: GS) or emerging foreign names such as HDFC Bank or Banco Itau. Though Citigroup has had its share of problems of late (thanks to subprime exposure), recent earnings showed just how well its global consumer business continues to perform.

And banks aren't the only companies benefiting from global megatrends.

Get in on the ground floor if you can
"Remove yourself from your own cocoon ... and think about what is happening in the growth economies around the globe."

That was Bill's advice on how to find superior foreign stock ideas, and it is sound. Our Global Gains team was able to travel to India, China, Mongolia, Macau, Brazil, Chile, and Argentina for research in 2007, and we emerged with ideas we never would have found otherwise. That's a function of meeting management and investors on the ground in these countries. Not only do they provide color to the numbers they report in SEC filings, they also occasionally give hot tips about the companies they admire (often little-known to U.S. investors) that operate in the same markets.

But individual American investors likely don't have time for the same travel schedule.

While that's unfortunate for a number of reasons (The Great Wall and Iguassu Falls are two of the world's must-see attractions), recent events here in the United States have made clear two more global megatrends.

And yes, you must own them.

Global Megatrend No. 2: $4 gas
If you weren't aware that gas prices have been rising, you have been living in a cocoon. A gallon of gasoline costs $0.80 more today than it did at this time last year -- with the national average being $3.02 per gallon, according to the Department of Energy.

The gas price issue is among the top priorities for consumers, presidential candidates, and the media. (Heck, MSNBC even had me on two weeks ago to talk about what can be done.) And while everyone says they want lower gas prices, don't expect that to happen anytime in the near future.

There's simply too much global demand, too many pinch points along the way from ground to pump, and too much idiocy influencing energy policy around the world. Alternative energy research may offer some long-term relief, but demand for energy should be so huge by the time much of that comes on line (places such as China and India aren't even close to being fully "developed"), prices won't come down in response.

So buy energy -- but buy it with the intent to hold for the next decade or more. It's that easy. ExxonMobil (NYSE: XOM), with its massive reserves, is one easy answer, but there are other, better options. Brazil's Petrobras, for example, offers more exposure to that rapidly growing market. China's Suntech Power (NYSE: STP) pursues solar technology in another market with huge demand. While an expensive stock at the moment, Suntech's energy solutions cannot be ignored.

Global Megatrend No. 3: $4 milk
The price of food has been rising right alongside the price of energy. That, in part, is thanks to a spike in corn prices caused by ethanol demand. That spike has caused an increasing number of farmers to start growing corn and stop growing other grains, which has resulted in widespread sticker shock. After all, when grain prices rise, so, too, do the prices of things made from grain (bread and cereal) and things that eat grain (meat and milk).

Add record global demand to this equation, and you have another global megatrend.

Giants Monsanto (NYSE: MON) and Archer Daniels Midland (NYSE: ADM) have already been hugely successful in this brave new agricultural world, jumping 1,171% and 250%, respectively, in the past five years.

But these aren't the only stocks that stand to benefit. Strangely named Chinese dairy play American Dairy (NYSE: ADY) clearly has problems with management and internal controls (see the SEC's recently announced probe), but its milk powder products meet a very real and vital need in China. Our trip to Argentina also uncovered a small company whose investments in agricultural land in Argentina and Brazil should reap very real rewards very soon -- and it's one of the top picks we brought home from that trip.

Buy to own
Money, energy, and food: Those are three clear global megatrends you should make room for in your portfolio. It could be as easy as buying a big multinational name, or you may want to drill down and find a company in a specific country that's poised to profit.

For help with those specific stock decisions, join us at Global Gains. You can see all of our research and recommendations, including that top Argentine agricultural stock, free with a 30-day trial. There is no obligation to subscribe.

Tim Hanson owns shares of HDFC Bank. HDFC Bank is also a Motley Fool Global Gains recommendation. Petrobras is a Motley Fool Income Investor selection. Suntech Power is a Rule Breakers recommendation. The Fool's disclosure policy tries really hard ... really.