Once you get the weight under control, (Nutrisource) Pure Vita Grain Free Salmon & Sweet Potato might be an excellent choice. It is a very bland, limited ingredient formula (and without the ingredients you mention) with moderate fat from a good company. Many sensitive dogs do well on it.
I’d also recommend trying Timberwolf Organic’s Ocean Blue Classic formula (potatoes listed are sweet potatoes, not white), also an excellent tried and true formula many allergic and sensitive dogs have done extremely well on, though it has more fruits/seeds/herbs base ingredients than the Pure Vita GF formula. So if your dog is super, super sensitive and can’t tolerate much, I’d recommend taking baby steps with the Pure Vita GF first.
