BladdersRoom, have you ever had any help with your relationship to food/weight etc?
You bowel needs real food to process for it to function properly.
Digestion starts in the mouth (enzymes in saliva), continues in the stomach (acid), carries on in the small bowel (liver/pancreatic enzymes) which renders your small bowel content in to something resembling lumpy, watery 'soup' (apologies for the analogy). The role of the large bowel is to extract water out of this 'soup' which means the longer something is inside the drier and harder it becomes (which is why often the first poo of the day is much harder than any subsequent ones).
The bowel wall is muscular and contains receptors that when your bowel is active (often after breakfast when the gusto-colic reflex kicks in: something landing in your stomach makes your rectum want to move. That sensation is known as 'the call to stool' and should always be obeyed
) causes a peristaltic wave to push a stool out without much straining or pressing or eyes popping out.
While there can be a genetic predisposition to slower or fast bowel transit times, you can 'train' a bowel to become slower and more sluggish, less responsive than an active, well functioning GI system.
You need to eat, Real Food.
Sugar does not make you fat.
Fat does not make you fat.
Amounts of various foods can be more or less healthy for you, but really, we should just eat a variety of foods that our great-grandparents would recognise as food (no ready meals on a regular basis), eat when we are hungry and stop when we are full. We should eat mainly plant-based non-starchy food, fat and protein. Refined sugar is not required but the sugar in fruit comes with so many vital vitamins, minerals and micronutrients that it pales in to insignificance. And most of us could do with being far, far more active than we are as a rule.
Bisacodyl is a 'stimulating' laxative. Chronic use will make your bowel MORE lazy and will make chronic constipation worse.
Please go and see your GP and get some RL advice: on your food issues and how to manage your constipation safely in the long term.
Sorry about the assay. Your issue/s is/are common ones but really are very addressable.