Good luck on your search for answers.

When I first found out about my condition I was told by

a dietician to give up red meat, sugar and most processed

foods.  This is almost 20 years past and as I approach 80

I am very hapy with my change in diet.

best to you

Snap! (By the way, ABBA, I love your songs)

I've suffered from IBS for about 40 years, and diverticular disease for the last 4. I have a colonscopy about 3 years ago which confirmed the diverticular disease, but found nothing else.

About 2 years ago, my doctor referred me to a dietician, who suggested I try the FODMAP exclusion diet.  This starts out by excluding many different food groups. If your symptoms then gradually resolve, the second stage is the cautious re-introduction of foods until you get a reaction.  You then know that this particular group is a trigger and should be avoided. 

There's no doubt it was hard work, as you need to cut out many foods, but at least it's not forever.  I nearly gave up a couple of times, and at first I thought I was wasting my time. However, when the time came to re-introduce food groups, I discovered that I react badly to beans, and mushrooms - both of which I adore!  I also found that I can tolerate small quantities of milk.  Cheeses are no problem, I'm pleased to say.   

I cut out the beans and mushrooms, replaced the lattes for black coffee with a small quantity of milk, and now have Lactofree and Almond milk at home.  With these minor changes, my symptoms have improved dramatically.  Since cutting out these triggers, I've only had a couple of flare ups and my gut no longer controls my life.  

Now, your triggers will almost certainly be different from mine, so it is highly unlikely that making the dietary changes that worked for me will work for you. I suggest you ask your GP to refer you to a dietician.