I have also suffered from constipation for most of my life, not really that bad, maybe opening my bowels every two-three days (every one or two days on Wai's diet but even then feeling incompletely evacuated most times), occasionally five days might elapse before I go. (Okay, not a pleasant subject

I am concerned because of this diagnosis in my family and I think I have inherited a 'lazy bowel'.
Wai's site is informative and helpful for me because it tells me what is causing my constipation and how to overcome it.
I knew constipation was a factor in causing bowel cancer but I didn't realize how crucial a factor until it hit one of my family members.
As I have said this family member was quite health-conscious and jogged everyday, was lean, and although it probably wasn't, tried to follow a 'healthy' diet, eating a lot of whole grains and veggies and fruit. Reading Wai's site makes things clear. The grains and the veggies aren't really healthy and neither were the legumes because all this fiber can cause small tears in the bowel.
I am wondering: can constipation cause cancer? Can trying to overcome it - ingesting much fiber - cause bowel cancer too? Which one is worse?
I used to believe before I came across Wai's site that constipation caused bowel cancer by allowing the bowel tract lining to come into prolonged contact with toxins and other mutagenics in food wastes, but now I am not so sure....
I am rather confused --- Wai says it's the tears that wear the bowel out and cause cancer - but isn't there a lower incidence of bowel cancer in Africans who have a higher roughage diet than westerners? So leading to presume that roughage is protective - unless this is a confounding factor and not related to the cancer issue, as many doctors and researchers make it out to be ..
And what about somebody who was constipated (life-long) and had a high-fiber diet (to overcome it)? What is more likely to have caused the cancer - the constipation or the fiber?
And if one is genetically prone to being constipated, shouldn't one try to eat more high fiber foods - eg. eating the whole fruit instead of juicing - to prevent the unhealthy and some say bowel-cancer promoting constipation - or is the cure worse than the problem - that is, a high fiber diet is the cause of the cancer rather than the constipation?
I am easily constipated because even when I am relatively strict on Wai's diet, only sticking to 15g protein, just eating one slice of bread or having milk in my coffee can make me constipated for a few days (hard stools and having to strain and a sense of incomplete evacuation and not wanting to go for days).
But if I try to overcome this by eating loads of fruit, especially the fibrous kind, eg by not juicing any of the 1.5 to 2 kg of fruit I eat, isn't that creating tiny wounds in my bowel?
And isn't Wai's high fruit-content diet a high fiber-diet one (if one does not do any juicing - pre-civilization man did no juicing I think)? And therefore a bowel-cancer promoting one (the fiber from the fruit pith and cellulose structure of say an orange causes small tears in the bowel)?
Not trying to be argumentative or attack Wai's theories - just trying to work things out because I am a bit confused and also concerned having the family history I do and all.