The Atkins and South Beach diet crazes caused strong demand for high-protein, low-carbohydrate foods. One such beneficiary, the lowly egg, saw its commodity price soar near 20-year highs. Cashing in on the twin blessings of demand exceeding supply and soaring prices was the U.S.'s largest egg producer, Cal-Maine Foods (NASDAQ:CALM).

From a December 2002 split-adjusted low of $1.395, the stock soared to a March 2003 split-adjusted $21.705 all-time high. In Wall Street parlance, that was a 15-bagger in 15 months. That's quite a price explosion for a stock with the Nasdaq trading symbol of CALM.

As egg production rose to meet and then exceed demand (oh, those commodities!) and the diet crazes ebbed, so has Cal-Maine's stock. At $7.37 today, it is down 66% from its all-time high set one year ago.

The company reported third-quarter results on Monday. Net sales fell 39%, from $165 million year to $101 million, and net income crashed 90% from the comparable quarter last year, from $23.9 million to $2.4 million. According to the company, the barnyard culprit -- excess supply in the industry -- is being corrected. Still, the company has reported a less than encouraging net loss of $3.8 million over the past nine months.

The good news to cluck about is that grain prices -- grain is chicken feed, mind you -- are lower than they were last year because of a large corn and soybean crop in the fall of 2004. Since grain costs average 55% of production costs, that is very good news -- at least for now. Everything commodity-related (grains, eggs) has its cycles, and while the company's on the good end of things at this point, those tables could turn within a few years, or perhaps even sooner.

Also wise on the company's part was using the boom's cash flow to improve its balance sheet, bringing debt down from $96 million at the end of 2003 to $23.5 million today.

But there are still reasons for concern. The next two quarters (running through August) are seasonally the weakest for egg prices. Therefore, investors might do well to walk as though they were on eggshells -- Cal-Maine's underlying profitability is tied to the relative strength or weakness of commodities' markets, making it an uncertain play at best.

For investors looking for faster growth and a healthy product, too, consider Motley Fool Hidden Gems recommendation Fresh Del Monte Produce (NYSE:FDP). The company trades at 11.1 times forward earnings and pays a 2.6% dividend.

Investors looking for companies that provide value-added food products and pay strong dividends (but were not diet craze beneficiaries) will want to consider two Motley Fool Income Investor recommendations. Sara Lee (NYSE:SLE), with a 3.6% yield, is restructuring to help it achieve better performance. Ketchup king H.J. Heinz (NYSE:HNZ), with a 3.2% yield, has a stable of strong brands to provide long-term growth.

Fool contributor W.D. Crotty does not own shares in any of the companies mentioned but is considered by some to be nuts. Click here to see The Motley Fool's disclosure policy.