Paul Campos argues that is is in an article at the Daily Beast, wherein he claims that the characterisation of obesity as a harmful situation, to be eradicated through government intervention in the behaviour of the young, is functionally equivalent to the discrimination against gay people that arose from false beliefs about homosexuality being unnatural.
I can see a couple of reasons to be sceptical of this equivalence. Firstly, being gay is not harmful. It doesn’t endanger your physical or mental health (particularly not once other variables are controlled for). By contrast, there are a long list of harmful consequences from obesity, many of which are more harmful to obese children than to those who become obese later in life. Secondly, and dependent on the health objection, there is an obligation on governments to protect the well-being of their populations (even more so for countries other than the USA, who have ratified the ICESCR, but even for the US, which hasn’t). That obligation provides reason for governments to do things in the obesity case that isn’t present in the gay case.
Despite these initial concerns, it is a very interesting article, do go read the whole thing.