Like many men I used to read in the bathroom until I'd seen enough men with hemorrhoids over time whose problem, more or less, seemed to be aggravated by this habit. There is some dispute over whether this practice contributes to their cause or to flaring them up.
To date, I've been lucky to escape this affliction but then again I really don't have a job that demands repetitive bending or heavy lifting, the heaviest thing I lift being a tackle box or cast net.
Statistically, more men than women read in the bathroom, and more men than women have hemorrhoids. Perhaps this reading habit of men, sitting beyond Nature's call, combined with straining, is one reason there's such a disparity. Other explanations could be that women eat more fiber than men who tend to be bigger meat eaters. The other being that men, in general, engage in tasks that involve heavier lifting. But perhaps overtime toilet sitting can cause a cumulative weakening of the anal sphincter muscles allowing the stretching of hemorrhoid veins. Something that might be especially made worse in men with large bellies that exert downward pressure on the rectum when assuming the toilet posture.
A skinny pedicurist I saw once affirmed this explanation. She, who having worked for nine years repetitively bending over clients' feet, had one morning stepped out of bed and turned to walk to her bathroom and suddenly fell to the floor. She slipped three discs in her lower back, the result of the cumulative weakening of spinal ligaments from repetitively assuming, day after day, a bent-over position to do her work. So it's not farfetched to consider the same process might facilitate one literally reading their hemorrhoids into a prolapsed state.
Some guys do more than just straight read -- they task. A real estate agent once shared with me that he considered tending to Number 2 to be a waste of time unless you were doing something. So he would compare real estate listings because he said he was unable to finish within a minute. He may have been one of these types who evacuates the colon in waves. Such people, if in a hurry, will mistake one wave to be the last when there are two more coming down the pike. Such a person is subject to being accused of using too much toilet paper.
But a friend once shared that her husband, instead of reading, often balanced their check book while sitting on his throne. I'd consider him special. There's something about numbers and mathematics that just doesn't seem to mesh with the act of evacuating one's colon.
The same applies, in my humble opinion, to the number counting of calories in preparing food (I can hear the dieticians screaming). But I've never met many men, if any, who've been able to do it successfully or for any length of time. The lucky ones have a lady in their life who help them with this task.
Before I ceased the habit, for the most part, I realized like the real estate agent that some people have a compulsion to be "doing something" while "doing one's business". It was difficult to stop cold turkey. So like some smokers who've quit by reducing the number of cigarettes smoked each day or week, I tried reading less and less interesting material, arriving quicker at being bored. But I had to be selective because some books are already so full of crap it would defeat the purpose -- like anything written by Dan Brown.
I eventually succeeded but not before running the literary gamut with a range of material, eventually icing the cake with an old book-sale philosophy book, a thick tome by Soren Kierkegaard.
And finally, aside from hemorrhoid prevention, contagious illness must be considered if you are reading in the bathroom books checked out from the library. Some studies show that when you flush the toilet there's a microscopic plume of aerosolized contents that ploofs into the room, if the lid is up. Cultures from bathroom items, including toothbrushes, have revealed fecal bacteria to be present upon them. One can assume that such a plume could also carry contamination onto one's library book, which soon will be returned.
Anyway, maybe it's a good idea to not read too long. And perhaps when you're done, consider closing the lid first -- for what it's worth.