Actually, I gain weight pretty easily, especially since my 40th birthday. I have to pay attention to everything I eat and I have to hit the gym at least 4 times a week to maintain my weight. This is not easy. I have to earn my body.
I am 5'8" tall. I topped out a couple of years ago at about 150 pounds and decided enough was enough. I was down to 130, but since I lift weights, I'm carrying a fair amount of muscle these days, so right now I'm ten pounds heavier. I wear a size 6 or 8.
Some of my cousins have the same tendency to gain. Most of them are taller than me, the women average 5'10" to 6'2", the men range from 6' to 6'8". All of them are older than me. I watched two of my female cousins change from curvy, athletic girls to 400 pounds plus, just because they did nothing and ate everything in sight.
One of them actually died because she needed a bone marrow transplant and no surgeon would touch her unless she lost at least 50 pounds. She complained and whined, never lost the weight and died of leukemia out of sheer laziness. Essentially, she commited suicide through gluttony. She was only 52 years old in a family that easily makes it into their mid-90s.
So, yes, I know whereof I speak. I know precisely how hard it is to maintain a healthy weight. I know precisely how hard it is to lose the excess. I take full responsibility for all of the choices I make regarding my health, and I am damned if I'm going to end up paying for idiots like those blasted cousins of mine. They can kill themselves on their own nickel.