Fibres are components of plants that resist digestion in the small intestine, and reach the colon and act as a prebiotic. This means that fibre feeds bacteria in the colon. They include resistant starch. Cooking and cooling foods (such as potatoes and rice) that are high in starches, can convert those starches into resistance starches that can promote gut health.
Fibres are different from FODMAPs in that they ferment more slowly in the colon, and often require a community of beneficial bacterial species to digest them. Fibres are therefore a key ingredient in your diet when you want to promote beneficial bacteria.
Don't focus on promoting beneficial bacteria initially, when you are in the stage of removing overgrown microbes. The GAPS diet, for instance, eliminates fibres in the initial stages. This is why GAPS is so successful at rebalancing the gut because it’s starving bacteria out. It removes the bacteria that is causing the issues.
In my opinion, for most people, GAPS starves bacteria for too long. We should be removing the unwanted microbes as soon as possible through starving unwanted microbes and using antimicrobials, then introducing low FODMAP vegetables as quickly as possible. Low FODMAP vegetables will feed the wanted bacteria. As the wanted microbes become more abundant, they regain control of the colon.
Fibre is a crucial component of gut healing
. Any diet that restricts fibre should be short term only. There should be a plan to increase fibre when appropriate. If there is discomfort caused by fibre, the objective must be to remove the underlying reason for the discomfort. Fibre is a healthy and important part of the diet but, for some people, fibre restriction may be necessary for the short term.