The natural, unprocessed organic food market has been growing at a brisk pace on the back of heightened customer awareness about the health implications of fertilizers, pesticides and genetically modified food items. It is estimated that the global market for organic food would grow at an estimated compounded annual growth rate of 12.9% to $104.7 billion in 2015.

The market for organic food in the U.S. is predicted to exceed $80 billion by 2015. Even during the recession, the organic food market in the U.S. grew at a faster pace than the food market in general. It is this growth in the end market that has helped Sprouts Farmers Market (SFM -2.54%) co-exist with industry behemoth Whole Foods Market (WFM) and others such as Natural Grocers by Vitamin Cottage (NGVC -0.56%).

Solid results and strategies
Sprouts reported good numbers when it came out with its second-quarter results . Net sales increased 45% year-over-year to $622.4 million. This revenue growth was on the back of a 10.8% increase in comps, the opening of six new stores during the quarter, and the acquisition of Sunflower Farmers Market completed last year. Comps increased due to higher store traffic and also an increase in the basket size.

Sprouts also reported diluted earnings per share of $0.10, a 100% increase from the same period in 2012 .

Sprouts management thinks that it will be able to sustain a store growth rate of 12% per year. It has 19 stores planned for 2013 and 20 stores planned for 2014. For the current year, the company has already opened 17 new stores. Management believes that there's scope to grow to over 1,200 stores across the nation as the U.S. supermarket and grocery market industry is worth more than $550 billion annually.

More intriguing options
The likes of Whole Foods have been plying their trade in this market for longer. Whole Foods is the biggest of the three companies discussed here with a count of 351 stores spread across the U.S., the U.K. and Canada. Its third-quarter results were good as revenue increased 12% year over year to $3.1 billion, in line with consensus estimates. Earnings increased 20% year over year to $0.38 per share , also in line with consensus expectations.

Going forward, Whole Foods is planning to expand into impoverished neighborhoods with smaller-sized stores. The first such store is planned in Englewood, and is slated to be operational in 2016. If this model succeeds, then Whole Foods might open several such stores going forward. In addition, it also has strategies like "flash" sales on specific items in place (where consumers can buy the item for less), apart from money saving offers through discount coupons on its website in order to drive traffic to stores.

Natural Grocers by Vitamin Cottage is the smallest of the three with a footprint of 65 stores across 13 states. The company did pretty well as far as comps were concerned in the previous quarter, recording growth of 11.6%. This was the highest among the three, and is expected since Natural Grocers has more room to grow on account of being the smallest.

On the back of such strong comps, revenue increased 30.55% from the year-ago quarter to $113.2 million .

Looking ahead, Natural Grocers plans to add two new stores in the current fiscal year and 15 in the next fiscal year as a part of its growth strategy. This means that investors can expect greater growth next year and beyond as the company steps up its store expansion initiative.

In addition, Natural Grocers seems cheaper when compared to Sprouts. The company's trailing P/E of 90x is half of Sprouts, which trades at a multiple of 186. Moreover, Natural Grocers' earnings are expected to grow at a CAGR of 29% over the next five years while Sprouts is expected to grow at 26%.

Conclusion
Given the opportunity in the organic food market, all three companies are expected to record good growth in the future. Conservative investors could consider Whole Foods as it is more established, has a wider store count, and trades at a relatively conservative 40 times earnings.

The more aggressive investors should consider taking a look at Sprouts or Natural Grocers, both of which are expected to grow at a terrific pace in the future. However, Natural Grocers' lower P/E ratio as against Sprouts could turn the investing decision in its favor.