I know this is my fault - I have tried to do something about his weight but it has been a difficult year.
DS is 8 (9 next month), is 138cm tall and weighs 8.5 stone :(
Please don't flame me I know how bad this is.
He is OBSESSED with food. Along with computers it is the thing he thinks/talks about the most. He loves eating and loves to eat large amounts. He was always a bit chunky and we kept an eye on it but in the last 2 years it has gotten extreme. Last year DH and I were refurbishing our house as we needed more space and couldn't afford to have the builders do anymore than the foundations/brickwork. It was very stressful and took a lot of time - both DC spent a lot of time playing together and using the PC at weekends. So he has been very inactive.
He was diagnosed ASD in Oct and was also diagnosed earlier in the year with dyspraxia. He struggles with sports and hates doing group activities (they make him anxious). He just wants to eat and play on the PC.
I get him out walking the dog each day but she only walks 30 mins a day and slowly (bulldog) so it isn't making any difference. Everything else he moans and whines and has meltdowns over (swimming classes, ju jitsu classes etc).
I limit his snacks but he does sneak food if I'm not looking. He has meltdowns over food and how much I let him eat.
Last year was so stressful I feel like I almost gave up. So yes I have done this. I do feed him healthy food but the portion sizes are too big. He still says he is hungry even after that though. He is always hungry.
My MIL has been saying for a while that I need to do something which is upsetting but today my parents pulled me aside for a conversation. I found this very upsetting as my own relationship with my parents was very difficult as I was a slightly chubby kid and from the age of 11 until I had my kids at 25 they nagged and shamed me about my weight constantly (bribing me with money, saying they were embarrassed by me etc). Now they are saying how worried they are about DS and I know they restricted food and weighed him this weekend (DC stayed with them as we were at a wedding). So this has bought up past issues for me and I have spent several hours today crying.
The fact is I don't know what to do - I am torn between trying my best to change his diet and exercise with all the difficulty that comes with that and damaging his self esteem by just saying look you are fat we need to sort it.
He clearly needs to lose weight not just maintain until he grows as he is too big.
Where can I get help - I can't find anything in my area? Do I go to the GP? But then I will need to take DS and possibly make him feel like shit when I say to the doc my child is very fat 
Any ideas appreciated. Thank you xx