We all go through phases of appetite loss. Yet when children and animals stop eating, many people panic and they are unceremoniously taken to a medic.
Yet, in many cases, there is a perfectly logical explanation for the lack of appetite that the body is addressing just fine. Medical interference may not be the ideal solution.
The most common reason for a lack of appetite is a digestive issue. It could be acute from say, eating something inappropriate or harmful as you have in food poisoning. Then a healthy body will have no problem vomiting up the harmful ingesta, possibly a few times, then having a period of rest, to recover just fine.
An unhealthy being or someone very young, old or frail may need help to recover, so they would need monitoring to see how they were managing.
Eating food that is inappropriate for the species can lead into a chronic loss of appetite over time. There may be hunger, but the body senses the same old garbage and pulls away. The body gets to a point when any more will start to tip them over the edge, so stimulates nausea.
This is common in cats fed commercial cat food, Cats are highly sensitive beings and can’t tolerate the combination of inappropriate food and toxins forever. It shortens their lives.
Dogs are not quite as sensitive as cats, but will have similar problems when fed commercial dog food.
Horses can’t vomit, so when they eat somethng inappropriate, they’re liable to get colic. This is much more serious as it can be fatal. So we should be thankful we do have this ability of vomiting, unpleasant though it may be!
Children are more fortunate, at least the older ones, as they can tell you what they feel and what they think was the problem.
Vomiting repeatedly means you may become a bit dehydrated, but a healthy body will easily recover from that. And I believe you’re better off allowing that.
Those who are very young, old or frail, as well as anyone who is not in robust health, are likely to need help to recover. Dehydration can cause problems, but I suggest it isn’t as bad as the medical industry like to portray.