I have to agree with anad64.
Due to health issues, including thyroid - some people will take longer to shed the lbs. Just because your mind tells you, you want to lose weight, your body doesn't always agree - example of that is in even healthy people - called plateau's. Your body sometimes does its own thing.
I am not saying it's not impossible to lose weight - it's very possible, but everyone is different.
FYI - No, I don't have a thyroid problem or any other health concern that would stop me from losing weight. I'm just saying, yes, 95% of people are just overweight because of themselves. The other 5%, we have to give some slack.