Deathfat

it's made of people you probably see everyday^([sic]) and don't even think are fat, let alone deathfat.

Source: wiktionary

To put it more succinctly, I am death fat. I am superduper really-for-real mad fat. I am the kind of fat where doctors are friendly until they get me on a scale, and then after that they get very quiet.

Source: wiktionary

Death fat individuals may find that smaller fat people are taking up more space in fa(t)shion and are more commonly seen in these blogs.

Source: wiktionary

Some US fat activists distinguish between ‘inbetweenies,’ who are relatively ‘small’ fat people who enjoy privileges such as ‘passing’ as thin or ‘on their way to being’ thin, and ‘death fats,’ who suffer the worst of the sanctions society places on fat people (McMichael, 2010).

Source: wiktionary