The hearty stew adds your health regeneration to your base damage but the heretic has negative health regeneration so theoretically if you reduce your base damage enough with something like tonic affliction and you hit an enemy would it be possible to heal it or does hearty stew not go negative
after some more thinking I've realized the best way to do it would be to get transcendence to keep your health constantly at max because health regeneration doesnt effect shield and your health is technically at one and in order to reduce your damage enough to see if it would go negative taking a lot of spinal tonic until your stats are reduced so dramatically that your base damage is miniscule also doing it on drizzle will increase your negative regen would probably be the only way to truly see if it works