Ha. This is a good one.
I LOVE pickles. Pickles are a crucial part of my occasional and variously effective diets. Pickles have ZERO calories. Unfortunately pickles contain near infinite sodium. All that sodium causes you to retain water — water the body needs to maintain homeostasis. This is how no calorie pickles will cause you to gain more weight than snarfing an entire Costco Family-Of-Man sized tub of Crisco.
Pickles: Sort of of Evil. But a yummy kind of evil.