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Did you miss last night's "Mad Money" on CNBC? If so, here are Jim Cramer's top takeaways for today's trading.

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GrubHub (GRUB - Get Report) : When high-flying stocks lose their mojo, investors need to beware, Cramer told viewers. That's exactly what happened with GrubHub, the online food ordering company that was all the rage when it came public in April 2014, but now has seen its shares fall 30% this year, below its IPO price.

When it debuted, GrubHub was touted as the usual "disruptive technology" that was supposed to change the world. And for awhile, it was, with 85% revenue growth its first year and over 30,000 restaurants as customers. The company was profitable and clearly had the mindshare of the public.

But then growth slowed dramatically, sending shares from a high of $47 to just $23 today as a parade of analysts downgraded the company. When it last reported in October, GrubHub missed on both the top and bottom line, with just about every metric showing that growth is slowing.

Making matters worse, GrubHub is preparing to expand into the competition-ridden field of food deliver, competing with the likes of Uber and Postmates. Wall Street is not convinced that this move will reignite growth, and Cramer said you shouldn't be either.

There is a price at which GrubHub makes sense, Cramer concluded, but at 33-times earnings, we're still not there yet.

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Popeyes Louisiana Kitchen (PLKI) : In an exclusive interview, Cramer once again spoke with Cheryl Bachelder, CEO at Popeyes, which today posted a two-cent-a-share earnings beat and a 6% rise in same store sales that sent shares up 6.6% on the day.

Bachelder painted a bullish picture for Popeyes, saying that her company continues to deliver flavorful food that people just can't get at home and excitement remains high across the country.

Bachelder was also bullish on Popeyes' international prospects, saying that she sees steady, consistent growth in both new units and comparable store sales in countries like Chile, Peru and many others.

Turning to issues here at home, Bachelder admitted that the real estate market for prime locations has gotten more competitive, but thankfully the unit economics of a Popeyes restaurant makes paying a little more for a great location worth it.

Popeyes remains committed to its stock repurchase program, having just authorized an additional $200 million.

Cramer said that Popeyes proves that not everyone is struggling in the restaurant space, some are doing terrific.

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Air Methods (AIRM) : In his "Homework" segment, Cramer followed up on several stocks that stumped him during earlier shows. He said that Air Methods, a medical transportation company, is not only an interesting niche business, but could also be worth $50 a share on a takeover. The company has been urged by private equity investors to take such a deal, but even with out it, Cramer said this stock too cheap to ignore.

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At the time of publication, Cramer's Action Alerts PLUS had no position in stocks mentioned.