One of the main factors are what did your mother eat, when she was before puberty, and what did you eat before puberty.
Children of immigrants are often fat, because their mothers came from a culture where food was scare but natural, and they now grow up in in a culture where food is cheap and contains lots of sugar. The epigentics now cause that they will store the sugar into fat, whenever available. Grand children of immigrants are often thin again. Because their parents already grown up in a culture where food was cheap.
So there are only a few things one could do:
1st - try to keep your children thin. Let them make sport, let them drive bicycle to school, and do not drive them by car. Avoid sugar, especially fructose.
2nd - its to late, once you left puberty. Only a hormone change could change weight. Women get a 2nd chance to get thin when pregnant or during menopause. But they normally get fatter.
3rd - So just try to live with your weight. Start a sport where weight is good, e.g. sailing. Every sailor is always searching for fat crew, as self loading ballast on the rail. Even if sailing does not feel like sport, you burn lots of calories by moving your body to balance the waves. You learn to move your fat fast, and to balance yourself, even with high weight. A few years sailing might only cause 10lbs of weight loss, but the health benefit is much bigger then just the weight loss. And the self esteem gains a lot, regardless if you win a race, or only sail recreational.