This is a really good reason to keep the food moving through at the correct speed and not hanging round too long, which is when the food starts to ferment and produce the gasses that cause bloating and toxins that cause other upsets in the body. You keep food moving by eating a healthy balance of raw fibrous vegetables, cooked beans and pulses and cutting down the amount of sugar and red meat you are eating.

You might have been recommended to eat bran 'fibre', because this is a substance known to draw fliud into the gut, however you will be better served to add an extra portion of pulses and vegatable fibre, like grated raw carrot and beetroot, into you meal instead. 

When you are looking for information on how to maintain good gut health this is a useful short video by Dr Mercola. If you decide you would like to add a good quality probiotic supplement into your changes, I can recommend Mannatech as a supplier of high standard supplements.  They follow all the standards and quality assurance practices Dr mercola suggests to look out for in a nutritional company.

This is part 1 of 2 - they are both worth watching