McDonald's (NYSE:MCD) has been a staple in conservative portfolios for years due to its consistent dividend and reliable growth. The fast food chain has over 35,000 global locations and had revenue of over $35 billion in 2013. When it opened in the 1940's McDonald's was primarily a burger joint. In line with the company's growth, it began to branch out toward the items that today make up its daily menu.

It hasn't been a secret that McDonald's has hit a bit of a rough road over the last couple of quarters. Same store sales have churned and consolidated, instead of growing. Promotions like the revamping of the McRib sandwich have failed to generate the attention the company hoped they would. The company is dealing with the major consumer shift to organics and health food, and has felt the stiff competition of casual upscale dining like Chipotle.

Arguably, you could make the case that the move away from fast food began years ago after Morgan Spurlock's documentary "Super Size Me" caused significant reform in the sizing and pricing of McDonald's products. Since then, the company has added salads and healthier options to their menu, while still continuing to sell their flagship products, like the Big Mac.

Morgan Spurlock's documentary into the sizing and pricing habits of McDonald's products spurred reform for the fast food maker and a shift toward a healthier lifestyle for consumers.

Companies like Whole Foods have dug into a growing consumer wide trend of moving into a healthy lifestyle, as well. Buyout rumors of Whole Foods are in the air this week as well, as its rumored that Florida-based grocery store Publix looks to further their angle on the health food craze.

In addition to the healthy push, companies like Taco Bell, a subsidiary of Yum! Brands (NYSE:YUM), is going after breakfast, which has been a staple for McDonald's since it was introduced in 1972. The company first pioneered the Egg McMuffin when studies showed that consumers would welcome a quick breakfast in the morning.

Meanwhile, Taco Bell has released a litany of commercials this year taking direct shots at McDonald's, including one that pins their breakfast as outdated and stale. The marketing has worked; Taco Bell's Waffle Taco has certainly been a talking point and is now looking like it may even be doing the job of giant-killer. 

Other fast food chains quickly caught on. Burger King (NYSE:BK) introduced their breakfast with the Crossaint'wich in 1983 and it's still a staple on their menu nowadays. In 2013, breakfast accounted for just $8.5 billion of Burger King's top line, compared to McDonald's, who posted $35.86 billion in breakfast sales for the year. Burger King certainly has plenty of market share to make up in breakfast, if it can start to close the gap between itself and McDonald's. McDonald's has roughly 31% of the total fast food breakfast market share. 

Signs of domestic struggle
The pricing upswing of causal dining (without a waitress) has risen over the past few years, leading consumers to once again consider fast-food options when they're opting out of waitress service. We can see the growth in this sector through the successes of companies like Panera and again, Chipotle.

Earlier last week, we learned that McDonald's same store comps for May beat estimates, but domestic comparables in the U.S. fell by 1%. 

McDonald's stated the following in their press release  regarding May comparable sales:

In May, U.S. comparable sales decreased 1% amid ongoing broad-based challenges.  McDonald's U.S. business is heightening its customer focus through service, value and menu initiatives to stabilize results.  During May, these efforts were reflected in the promotion of Dollar Menu & More offerings and breakfast including a focus on McDonald's popular McCafé coffee. 

While executives seem to try and be downplaying things a bit, it sure looks like the domestic pressure is on breakfast, as well as the company's dollar menu. Numerous local McDonald's locations in my area are constantly offering free McCafe samples to people that walk by in order to try and generate some awareness of their cafe brand. 

We all know that Starbucks is now trying to get into burgers and booze, McDonald's is trying to pull a reverse Starbucks and dip their hands into the craft coffee drink well. Is McDonald's having trouble defending the fast food meal that they once pioneered?

Foolish final thoughts
Despite this struggle, McDonald's isn't likely to be going anywhere anytime soon. This struggle for the company is going to force executives to keep going back to the well until they find something that can work in helping them out domestically.

Luckily, McDonald's has a balance sheet that gives them all the time they need to figure it out. With $16 billion in shareholder's equity at the end of 2013, McDonald's shouldn't feel too pressured to make major moves in a careless fashion. They have the time to carefully craft, and execute, a strategy to "get breakfast back." And Fool contributor Dan Moskowitz notes  that those in McDonald's have a history of being rewarded:

If you invested in McDonald's, then you have been treated well. For example, McDonald's repurchased 323.6 million shares between 2007 and 2013, it has raised its dividend every year since 1978, and its stock has appreciated 279.5% over the past 10 years. 

While for the short term, questions continue about McDonald's, for the long term it seems like McDonald's continues to be a sound investment.