Let’s begin by clarifying some terminology. By ethics, I mean the set of guidelines governing what a person should do. Putting it another way, a particular action is ethical if, all things considered, it would be better to perform that action than not. Ethical guidelines are further composed of moral and non-moral actions and virtues (or good qualities). Moral actions or virtues are other-directed. To have the quality of being generous (to others) is a moral virtue, and murder is an immoral action. In contrast, non-moral virtues are self-directed. To have the quality of being intelligent is a non-moral virtue, and to act intemperately is to exhibit a non-moral vice (at least according to Aristotle).
The above-mentioned articles seem to conflate two questions: first, whether there is such a category as non-moral vices; and second, whether health is related to moral action. Beginning with the first question, some people regard suicide as an unethical non-moral action, meaning it is a self-directed action they think a person should not perform.* A similar rationale could apply to other forms of self-harm, including excessive drug use, overeating or extreme sloth. One could counter the prohibition against self-harm by arguing that all humans should be free to act as they choose, so long as they do not harm others. Euba also suggests that longevity should not outweigh hedonistic pleasures. However, as I have previously argued, a truly devoted hedonist is going to have to work very hard to argue that a shortened life of pleasure would produce more net enjoyment than a longer life of moderated pleasures and reduced side effects.
To use a previous example of mine, imagine that you are caught in a burning building with an unconscious person of approximately equal weight to yourself. Ethically speaking, you should move that person out of harm’s way if you can do so without risking your own safety. The only obstacle to performing this action is your strength. But since a fully able adult human is capable of lifting his or her own body weight, to say you did not save this person because you chose not to cultivate your own physical abilities makes you morally culpable. In short, non-moral virtues (like health) may enhance your ability to act morally.
Returning to the critiques of Euba, Sandel and others, we can see that body composition, food choices and physical health fall under the category of non-moral virtues/vices. Euba and Sandel are correct in this respect since physical health is primarily a self-directed pursuit. At the most basic level, choices like whether or not to eat healthy or exercise have no effect on other people and are not moral choices. These actions alone do not target or affect other people and do not deserve interpersonal condemnation. It is only when physical fitness has the potential to contribute to moral action, e.g. when strength allows one to be brave and compassionate, when mobility allows one to display empathy and respect, when speed allows for cooperation and generosity (again, see The Ethics of Human Movement), that an individual’s health warrants praise or blame.