How do you know if your eating too much fiber? do you start getting a lot of gas?

Loose stool, bulky: Too much fiber can give excess gas (so can too little), bloating, big, bulky stools, and/or excessively frequent, loose watery stools. Depends on amount and type of fiber, other diet components, fluid intake, meds, gut function/disease. Aim for 25-35gm/day, preferably from diet; not all at once. Supplements if diet inadequate.