After the bell Tuesday, popular momentum name NutriSystem (NASDAQ: NTRI) reported earnings. While the earnings report was extraordinary -- 70% year over year growth, handily beating analyst estimates, and so on. The company's third quarter guidance cut was enough to send the shares down about 15% in after-hours trading.

While this sounds crazy, I think the company could very well be lowballing its guidance for a variety of reasons. First and foremost, I don't think NutriSystem executives expected the stock to react so poorly to the guidance cut considering the first quarter figures solidly beat the street. In other words, I think the executives expected the incredible second quarter to easily trump any news of a weaker third quarter.

I'm well-aware of the fact that the new weight-loss drug Alli could stand to hurt the company, but I think the primary reason for this guidance cut was to improve Wall Street's perception of the stock when they report next quarter. Faced with tough year over year comparisons from the Dan Marino campaign in Q3 of last year, the company wanted to have something to boast about -- crushing guidance.

While some will argue that the company is betting on higher TV advertising costs, I don't think the true squeeze from advertising costs will come until early 2008 when election campaign spending heats up dramatically and TV stations can increase rates due to the high demand.

I may very well be crazy, but I think NutriSystem is playing the guidance game. Even though the stock looks cheap here, I'd be careful.