If you cannot manage to lose weight yourself, if all of your past attempts have failed, then ask for help. (You are by no means alone. Hardly anyone with weight issues changes all by themselves. Successful losers do it with help.)
Don't be afraid. You're not a failure if you get help -- you're actually strong and successful. You'll succeed through the support of others.
There is help available from many sources: a friend, family member, therapist, a pastoral counselor, minister, rabbi, registered dietician, physician, psychologist, psychiatrist, imam, sensei, monk or nun.