There is a temptation to make the investing process more complicated than it really is. The main factors determining your returns are your savings rate, diversification, and time in the market. Yet many investors instead focus too much on today's financial headlines, which won't matter much in five or 10 years.

With that in mind, let's look at two stock investments that keep it simple. Buying and holding Procter & Gamble (PG 0.65%) and McDonald's (MCD 1.70%) shares right now could set your portfolio up for market-beating returns over the long term. Read on for a few reasons to like these two successful businesses today.

1. Procter & Gamble

What could be simpler than selling toothbrushes and laundry detergent? Procter & Gamble dominates dozens of consumer essential categories for which millions of people use products every day. That market position, combined with its efficient business, has produced fantastically stable growth for shareholders. P&G has raised its dividend, for example, in each of the last 66 years.

Wall Street is forgetting that impressive streak right now and choosing to focus only on the short term. P&G's business is under stress from rising prices, and sales trends could slow if consumers decide to trade down to value brands during a spending pullback.

P&G has made it through many past recessions, though, while maintaining its leading market position and high profit margins. Investors can also count on a steadily rising dividend to cushion their returns through any temporary slump. Set that payout to automatically reinvest, and you've got a built-in process for accumulating shares through any type of selling environment.

2. McDonald's

McDonald's is one of the best-performing stocks in the Dow Jones Industrial Average today -- and for good reason. The fast-food titan recently announced a blistering 10% comparable-store sales increase for the selling period that ended in late September. It successfully passed along higher prices without sacrificing growth in key metrics like customer traffic. "We are operating from a position of competitive strength," CEO Chris Kempczinski said in a late-October press release.

That strength is also evident in McDonald's profitability, which remains near 40% of sales even as costs soar around everything from labor to food ingredients. Compare that to other successful industry players like Chipotle Mexican Grill, and you'll see that the burger giant has a superior competitive stance.

Chipotle, along with other rivals, is targeting some of McDonald's market share by moving into more rural areas and focusing on drive-through services. Yet the fast-food leader has faced similar challenges in the past and has always navigated through them with help from its flexible selling approach.

Depending on the mood of consumers, Mickey D's can market more of its menu staples, its limited time offerings, or premium items like indulgent coffee drinks. Its ability to dominate a wide range of price points helps it grow sales and earnings through tough economic times.

That's a simple but effective approach that has served shareholders well over the last several decades. It is likely to continue supporting market-beating returns for this stock.