My DH suffers, he has always had 'bad guts', tired, lethargic but also a kind of skin rash. He'd been to docs and got nowhere, eventually went to a herbalist who suggested candida imbalance or 'leaky gut' as he called it.
Gave him some diet suggestions and some supplements and over a few months it improved, he no longer sticks to it religiously but can rein it in when he needs to.
No yeast is the main thing.........yeast extract is in loads of stuff as a flavour enhancer, stock cubes, tinned stuff, etc you need to read the labels but there's loads of stuff without it. No beer, but if you must have a drink then clear alcohol is ok (vodka, fine, Bacardi)
Likewise citric acid, added to loads of things like tinned tomatoes, puree, etc but again....read the labels.
Mushrooms
Anything fermented like soy sauce, vinegar, pickled stuff
DH's candida was also triggered by gluten, worth thinking about?
Supplements: caprylic acid, fresh coconut, garlic (fresh or oil capsules) and a good High dose probiotic.
The book that because googles is good as is Erica White's (google it too).
The diet is not that restrictive once you get used to it. Like I say, we did it for 3-6months to clear it up and then DH reigns it in if he feels it flaring up.
HTH