I wouldn't use 1 for overcoming adversity. Though I understand what you mean by how difficult and how trying it can be, being someone who has struggled with weight most of my life as well, and I understand how you could apply that to a mission in medicine, unless you are trying to be a physician that is focused around weight-loss, primary care, endocrinology with a focus on obesity, etc. But, if it has applicability that you say, I would definitely include it in your application somewhere.
2. Is not a good idea. I am really not trying to bash your adversity, trust me, I empathize youve been through so much in your life OP, so I apologize if that is what is being communicated. The divorce, though emotional and difficult, you said it yourself, you didn't actively do anything.
3. This is what would be the best I think. This is medically applicable and personally applicable. I am proud of you when you give that story, and I am just some random doctor on the internet.
Go with 3.
I hope that helps, friend.