According to Stan Lee and Nick Carter:
Powered by his mystical amulet, Kevin becomes pumped up and as strong as a roomful of weight lifters. Just like a tiny ant that can heft a potato chip that's many times its own weight, Kevin's newfound might grows exponentially, so if he needed to he could lift a 10-ton potato chip or even a Harrier jet.
(Just a small question - why would any one compare Kevy to an ant? That’s just crazy talk!)