Issues such as endocrine disorders, genes and mental orders.
Obesity is a very prominent issue that even i struggle with. So you have accumulated a lot of body fat that it may be harming your health? Yes, I feel my self having pains and struggling to do things that I didn't before. It's a mental and physical issue. What type of diseases does obesity lead to? I wouldn't say it leads to these diseases but obesity does increase the odds for things like cardiovascular disease, obstructive sleep apnea and even some forms of cancers to name a few. What is sleep apnea? I don't have the answer to that but for your obesity, is it due excess eating, not exercising, a genetic condition or a combination of them? Definitely eating and exercise,  what kind of genetic disorders make obesity a possibility though?
A few cases are caused primarily by genes, endocrine disorders, medications, or mental disorder.