Are you now or have you ever been on a health-food kick? To an extent, my wife and I try to have a healthy diet without going to extremes. We have done some of our grocery shopping at Wild Oats (NASDAQ:OATS). The produce is very good, there is a decent variety, and it is a little expensive.

Wild Oats reported second-quarter earnings this morning before the open. The number was $0.01 compared with the consensus estimate of $0.07. Ouch. Over the last few quarters, the firm has missed as many estimates as it has beaten, so a miss isn't a shock, but this big of a miss is surprising. The stock is getting taken to the woodshed, with a nearly 26% drop in trading today.

Revenues missed the estimate by $9 million, coming in at $251.7 million. Revenues grew by 3.9%, but same-store sales grew by only 1.5%.

The company said it was disappointed with the results. Management cited several factors, including the end of the grocery strike in Southern California and some cannibalization from opening new stores in existing markets.

Wild Oats wants to grow by opening more stores. This past quarter it took on debt of $115 million to fund expansion. While taking on more debt is not ideal, it shows the company is not standing still. In addition to new stores, the company is working on a store-within-a-store concept with Stop 'n Shop and an Internet distribution deal with Peapod.

Investing in grocery stores can be tough to do, even when they are niche players. Very rarely do the numbers look good. Wild Oats has single-digit growth rates, razor-thin margins, and a very low return on equity. These kinds of numbers are not unique with grocery stores, though.

The bigger problem is that Wild Oats plays second fiddle to Whole Foods Market (NASDAQ:WFMI), which has had its own perceived problems. Over the last three years, Wild Oats' stock price has so badly lagged Whole Foods that it is hard to believe they are in the same type of business. Wild Oats is expected to have slower earnings growth (17.5%) over the next five years than Whole Foods (20%). And Wild Oats is also more expensive than Whole Foods in just about every statistic.

So, in summary, Wild Oats is more expensive and is growing slower. The relationship between the two companies leaves me still wanting to shop at Wild Oats, but I will pass on the shares.

Fool contributor Roger Nusbaum is an investment manager and wildland firefighter in Prescott, Ariz. At press time neither he nor his clients owned any of the stocks mentioned.