Being that I am schooled in America, I am given a lot of stats regarding us as a nation, the average American intake is only 10 grams of fiber, the daily required intake for women is 25 grams and 38 grams for men up to the age of fifty. After fifty is should drop to 30 grams for men and 21 grams for women. In all actuality, one could eat 60grams a day, some countries even recommend more. A theory about the American DRI is that this set it lower, to make it more realistic for people who currently are at 10 grams.
There are two main types of fiber (soluble) aka fermentable fiber which dissolves in water and (insoluble) which does not. Within jimmyjoy-plennyshake are oats which is known for having soluble fibers, the reason why it’s referred to as a fermentable fiber is that essentially it feeds the good bacteria in your gut. This is where the alleged gas can come from, essentially the gas is bacteria poop. =)
I have a recommendation you can try to see if it helps you out, there is a fiber called Psyllium Husk that I recommend to my clients, you can find it here as an example https://www.pit-pit.com/psylliumhusk-gemalen.html you can start with 8 grams, split throughout the day. (it can be gradually increased up to 20 grams a day) This can help in theory due to Psyllium Husk having both soluble and insoluble fibers. The insoluble fibers can have the opposite effect of soluble fibers when it comes to gas production. Give it a try and let us know if it works, I am curious.
Last thing to mention, while consuming a diet that includes a fair amount of fiber it is recommended you ensure to drink enough water. Minimum is 8-10 glasses a day.