While I agree with most of what Scott posted, I think some research has shown that low carb, low sugar diets like SCD or low FODMAP work over the course of time and a benefit may not be immediately observed. These diets work to reduce bad bacteria populations and it takes many months to see those particular benefits. Hence any benefit may not be palpable or discernible in days or weeks. However, we have a board of posters who, like sports fans who want to see immediate results from their team, don't want to hear promises about improved performance some unspecified time in the future. These diets are not necessarily built to produce immediate results but over the course of time can make a difference.
There is no magic pill diet that works for everyone, and trial and error over the course of time is the best way to go. I am on an annual scope cycle due to Crohn's/inflammation of a chronic nature (and dysplasia pre-colectomy), and dietary changes I made in the past showed up on my scope results. I generally avoid processed carbs and sugars, and I feel like that has made a difference.