"Like-minded" doesn't have to mean they have the same goals for themselves as you do for you. They could just be supporting you in your goal. Dan John talks about this a bit, mentioning that when you have a goal it's best to set a date and tell EVERYONE about it. That way people will ask you about it and follow you up on it, you don't get to just quietly drop it.
Or you could make a bet. For example, at your next birthday party during your speech, bring out a 1kg tin of Pal, and say, "if I do not lose 10kg by my next birthday, I will eat this." The prospect of being public humiliated eating dog food, and the endless piss-taking from your mates as the date comes up, should be a powerful motivator