
I think it's very important to acknowledge that there's absolutely nothing inherently wrong with being fat, and that it doesn't by itself imply poor health, and certainly not moral deficiency, in any way.
Some of the ways I've seen this handled online, however, are concerning. Because there's also a push to say how "healthy" things like candy bars and sodas are, which obscures the damage the corporations who produce food enact on impoverished populations by making healthy, convenient food unaffordable to the poor. Cheap junk food is not equivalent to a healthy diet, and the corporations that make it the only practical choice for the poor are not doing them a favor. These corporations don't care if the people buying their products die young of heart disease or diabetes (which junk food contributes to regardless of whether it makes a person fat or not).
Again, this isn't about blaming people our society considers fat for their health problems (or erroneously blaming the fat itself). I want to scream at every health advocate who pushes this fatphobic ideology because it plays right into the very corporate hands that they often decry (in addition to conflating appearance and heath). This is a problem with how our society treats the poor--blaming the victim in order to incentivize them to indirectly absolve the perpetrators of blame by claiming that the food that's slowly killing them is actually good for them.
Furthermore, I believe that telling someone they're not morally deficient because the junk food they're eating is actually good for them still implicitly says that a person can actually be morally deficient simply by possessing a health problem. Otherwise why would it make sense to say that the food someone is eating is healthy so they shouldn't feel guilty? Why should someone feel guilty just for eating food that is unhealthy to them at all?