With 362 stores in the U.S., Canada, and the United Kingdom, Whole Foods Market (WFM) is one-fourth the size of Safeway (NYSE: SWY), which has 1,406 stores total. Sprouts Farmers Market (SFM -0.98%) is the smallest in the bunch with only 160 stores. Whole Foods stores average 38,000 square feet -- about half the size of a Safeway store and slightly bigger than a Sprouts store.

Whole Foods carries more organic and healthy products but much fewer national brands, cleaning products, snacks, sodas, and paper goods than Safeway. Sprouts products, produce, and merchandise offering is similar to Whole Foods. Based on its 2012 sales, Whole Foods is ranked the 12th largest food retailer by Progressive Grocer.

Safeway goes organic -- well sort of
You might not think of Safeway as an organic-grocery store, and you'd be right. However, seeing the trend towards healthier eating, the company has expanded its organic-product offerings, and not just with a bigger organic-produce department. Safeway has its own brand, O Organics, in frozen and prepared foods, snacks, juices, and more. The store also carries the Celestial Seasonings brand, which emphasizes its reliance on healthy organic ingredients. Organic dairy products and eggs are available, as well as some organic meats..

Growth for Whole Foods in both sales and number of stores
Company growth for Whole Foods is founded on opening new stores rather than on acquiring chains. This is a different philosophy than Sprouts, which acquired 38 Sunflower stores in 2012. According to their Q3 investor call, Sprouts has signed leases for 30 stores to be open between 2014 and 2015. Comparatively, Whole Foods opened 25 new stores in 2012, 26 in 2013, and acquired six stores as well. Interestingly from 2010 through 2013, the company had about three times as many stores in development as new stores brought online, indicating an aggressive expansion plan. Safeway is in consolidation mode, closing underperforming stores.

Comparable-store sales for Whole Foods, whose fiscal year ends at the end of September, increased 8.7% in 2012 but only 6.9% in 2013.

Looking at the industry in 2012, natural-product sales through retail channels increased 10% over the prior year, according to Natural Foods Merchandiser. While Whole Foods did see a substantial revenue increase in 2012, it was below the industry's performance.

Total sales for all Whole Food stores reached $12.9 billion in 2013, a 10.3% increase from 2012 with 27 more stores. However, 2013 was a 52-week year, while 2012 had 53 weeks. At average weekly per-store sales of $682,000, that extra week of sales adds up. Costs of goods held steady at about 64% of sales from 2012, resulting in a gross profit of $4.6 billion or 36% of sales. 2012 gross profit was $4.2 billion and 36% of sales as well. Operating income increased 18.7% to $883 million. Sprouts' operating income for the third quarter of 2013 was 5.8% of sales, while Whole Foods' was 6.8% for the year.

Whole Foods does limited media advertising, but relies on its Whole Deal in-store circular with discounts, specials, and deals. The Whole Deal flyer is online, so it's not mailed or included in newspapers. Sprouts and Safeway, on the other hand, include flyers with weekly specials in the newspapers and mailings to households. Whole Foods says it relies on word-of-mouth by its shoppers rather than paid advertising and uses the money it would have spent on media placement on "community nonprofit partnerships," as the 2013 10-K report terms it.

Whole Foods gives the world a hug
Whole Foods is dedicated to seafood sustainability, animal welfare -- it recently stopped carrying live lobsters because the stores couldn't provide adequate aquarium facilities -- and local farmers. That's just the beginning. The company stresses whole-body health, nutrition, and a clean and green environment. The 2013 annual report says it best: "With great courage, integrity and love, we embrace our responsibility to co-create a world where each of us, our communities and our planet can flourish-all the while, celebrating the sheer love and joy of food."

All of this dedication to the environment, organic products, and healthy foods comes at a cost. Prices are higher at Whole Foods than at Sprouts and Safeway. The company says its stores are located in premier real estate, which is another way of saying in upper-middle-class locations. That makes sense with the higher prices and emphasis on organic, healthy eating.

Risky business
Out of the top seven Whole Foods executives, five are more than 60 years of age, including the two co-chief executive officers, the president and chief operating officer, an executive vice president who also holds the title of chief financial officer and the executive vice president of growth and business development.

Loss of key management positions is mentioned by the company as an inherent risk. While 60 is not necessarily retirement age, it is an age where health problems can start to arise. The aging management team is something to be concerned with, although they probably have a healthy diet.

Another risk is the reliance on United Natural Foods, which supplies about 32% of the products found at a Whole Foods Store. If UNFI decides to do business elsewhere, raises its prices or changes its payment terms, it would have a significant impact on Whole Foods.

To invest or not to invest
Whole Foods has significantly improved each year, and 2013 was no exception. The concerns of consumers to eat healthy is not a fad that will fade away. I also like the fact that the company focuses on improving its stores through its employee teams and team leaders. Fortune magazine named Whole Foods as one of the "100 Best Companies to Work for in America," and I think it might be one of the best investments out there as well.

Note: A previous version of this article incorrectly stated the Sprout's planned store openings for the coming years. The Fool apologizes for the error.