U.S. GDP may have only grown by 2.5% in the first quarter, but you wouldn't know it by the market indexes like the Nasdaq Composite,  which have hit a 12-and-a-half-year intraday high for 18 (not joking) consecutive trading days! For skeptics like me, that's an opportunity to see whether companies have earned their current valuations.

Keep in mind that some companies deserve their current valuations. Coal miner Alliance Resource Partners (NASDAQ:ARLP), which is run as a master limited partnership, reported yet another record profit in the first quarter and boosted its quarterly payout yet again. By locking in long-term contracts, Alliance Resource has nearly eliminated its exposure to currently weak coal prices and is able to count on steady and growing cash flow.

Still, other companies might deserve a kick in the pants. Here's a look at three companies that could be worth selling.

One step at a time
Given the tripling we've seen in shares of biotech company MannKind (NASDAQ:MNKD) over just the past six months, you'd almost assume that investors have written an approval from the Food and Drug Administration for inhalable insulin Afrezza as a certainty. MannKind has received ample backing from its CEO, Alfred Mann, who helped arrange for a large secondary offering, in which his own company, the Mann Group, purchased 40 million shares of MannKind stock. In addition, the company is getting close to being done with a new round of patient trials for Afrezza, so investor excitement is building.

While I find the concept of inhalable insulin very intriguing, the practical application isn't that simple. Afrezza has already been sent back to the drawing board once by the FDA and could have a hard time catching on even if approved, if history is any indicator. Pfizer's Exubera, which is an inhaled insulin that was approved in 2006, was pulled off the market just a year later following extremely weak sales. Afrezza will need to demonstrate drug safety and, of more concern, satisfy the FDA in terms of the production and delivery device protocol, which is no easy task.

Another sticking point could be pricing. The prospect of inhaling insulin definitely sounds more pleasant than an injection, but if the pricing isn't right, then consumers and physicians will continue to opt for injectable insulin.

At $1.6 billion in market value, I feel there's considerably more downside potential than upside at these levels and would suggest looking elsewhere within the insulin space for a "good deal."

This one is actually a bit painful because I actually like Whirlpool (NYSE:WHR) as a company over the long run. As an investment in the interim, however, things are looking a bit frothy and now could be the time to send these shares down the drain.

The biggest boost to Whirlpool's bottom line is coming from a mixture of cost-cutting, share repurchases (of which it still has approximately $350 million remaining under its current plan), and an improvement in U.S. new home sales, which should help boost appliance purchases. I'm definitely not going to take these improvements away from Whirlpool shareholders who've experienced a tremendous boost in its underlying share price, but I have to wonder, where are any further growth prospects going to come from?

Europe is absolutely not a region that's going to contribute anything positive to Whirlpool for what I figure will be another one to three years. Austerity measures across Europe and very high unemployment levels are constraining housing markets across almost the entire region, which will assuredly hurt appliance sales.

In the U.S., I would expect things to slow as well. The bulk of Whirlpool's sales came as buyers began snatching up existing new-home inventory. With housing inventories now at multiyear lows and homebuilders enjoying the fact that they have pricing power again, you can rest assured that inventories won't rise dramatically anytime soon. That puts Whirlpool in a growth bind unless it can pass along sizable price hikes to consumers, which I just don't see happening.

Even with a forward P/E of 11, Wall Street's forecast sales growth rates of 2% this year and 4.5% next year paint a relatively unattractive formula for future price appreciation over the next year or two.

Send this stock back to the kitchen
I admit to already being hyper-critical of the restaurant industry because of cutthroat pricing practices among peers, strained consumer spending because of higher payroll taxes, and the always looming threat that food prices will soar faster than the industry can raise prices. These provide for me more than enough reasons to suggest sending Bob Evans Farms (NASDAQ:BOBE) back to the kitchen.

Bob Evans is in the midst of a pretty sizable transformation, which saw it sell off its Mimi's Cafe brand earlier this year as it had been a notorious drag on same-store sales. Going forward, Bob Evans will be focusing on its restaurants and on its BEF Foods segment to drive growth. This is a case where I do agree with the actions being undertaken by management to trim the fat, but I simply can't get behind the rapid appreciation in Bob Evans' share price given its sketchy growth prospects.

Inclusive of Mimi's removal from its bottom-line results, Wall Street anticipates revenue will retreat 5% this year and up to 14% next year. The company will be doing what it can to cut expenses and pass along price hikes to consumers, but I just don't foresee same-store comparisons rising much more than 1% with consumer spending figures remaining weak. Unless something drastic changes here, this is a multiple I'd expect to fall over the coming quarters.

Foolish roundup
This week it's all about whether or not these companies can live up to expectations. Sales growth at Whirlpool and Bob Evans certainly leaves a lot to be desired for investors, while MannKind, even if it does gain FDA approval for Afrezza, still has a lot to prove with regard to sales and marketing of the drug.

I'm so confident in my three calls that I plan to make a CAPScall of underperform on each one. The question is: Would you do the same?