Being fat clearly disables one. But there is a limit on how much such a fact means authorities should throw money at fat folk. It's an unfair cost to the taxpayer. It is this automatic, 'Oh it's a disability, here's some money', attitude that needs ditching.
Unfair taxing of the public or specific groups of the public should never be encouraged. Folk should contribute according to what they get out of being part of society. And there needs to be a very good reason to interfere in someone else's lifestyle. Authorities think they have a right to do that anyway, which they don't, and they need no encouragement. Quite the reverse.
If there is a clear case of a mental issue whereby an individual is having problems with their weight, then fair enough, they should be given all the help they can to lose it and return to being healthy. But neither pilloried for their mental or hormonal or whatever is causing it, issue, nor funded to keep on with it. There are sensible balances to be reached that is neither maltreatment and scorn, nor letting them destroy themselves or allow folk to facilitate the same.
Help to get back to normality is what is needed. Not funding & aid to remain wasting their life.