Virtually all plant tissue will support certain gut bugs, but we generally don't reach a toxic threshold unless we eat the same one monotonously. Gut biome is still pretty mysterious but it seems like a rotating variety of leaf, stalk, root, and fruit fibers will foster a healthy equilibrium. Massive gas indicates a bacteria party so maybe that particular species is getting rowdy and needs to be starved down for a while?
Lots of: urban hiking, cycling, sprinting
Lots of: fresh meat, seafood, eggs, organs, tubers, starchy fruits, low-energy plants, meat fat, dairy fat, oily fruits
Some: cured meat, dairy protein, sweet fruits, rice, peas, tree nuts, oily seeds
Minimal: soy, refined proteins, sugar, liquid carbohydrate, grains, beans, refined oils, peanuts