What do you call it when you gain weight fast, and lose weight easily?

What is a good exercise to lose weight fast?

I want to lose some weight this summer fast and I was wondering if there is a specific exercise I should do to lose the weight fast and easily. I am not looking to buy “Insanity” or anything like that, I simply want to know an exercise that will help me lose some weight, fast. Any exercises that make you lose calories fast?

p.s: I also do not want to use weight loss pills.

How to lose weight fast and easily in a month?

I need to know how to lose weight fast and easy. I am getting married
in the fall and I can’t seem to lose the last 10lb. I’ve tried
exercise but it’s not really making a difference and I can’t diet too
strictly because I have food allergies. I’ve heard of reaching a
plateau when losing weight, could this be what that means? I don’t
mind taking supplements so long as they don’t contain hormones. I
don’t want to suppress my appetite, I just want to know how to lose
weight fast and easy and healthily xx