It's the other way round: people love being judgemental about the diet and exercise habits of others, since it used to be a difficult-to-fake social signal, and

It's the other way round: people love being judgemental about the diet and exercise habits of others, since it used to be a difficult-to-fake social signal, and apparent weight and fitness is an easy metric for that. See also: white people being judgemental about people with darker coloured skins, to the extent that they may sometimes invest in skin lightening, meanwhile white people are investing in artificially darkening their skin with tans (because it's a symbol of conspicuous consumption, the ability to go to sunny places).