There is no real known cause and effect of hemorrhoids and generally speaking all advice is based solely on case studies, but there are some basic things you can do and change in your lifestyle to help prevent the irritation and growth of hemorrhoid swelling.
One effective way to prevent hemorrhoids is to have normal bowel movements and do everything possible to eliminate the stress and pressure which exacerbates hemorrhoids.
If necessary change your bathroom habits.
If it takes longer than 2-5 minutes to defecate, you should consider cutting down that time.
As you hang around longer in the toilet bowl, there's a chance that you will strain the anal veins.
So don't even think about reading a novel or a magazine while defecating.
The next effective way to prevent hemorrhoids is by keeping the stools soft which prevent constipation so they pass easily.
Regular exercise, even daily walking, and an increase of fiber in your diet will help reduce constipation and straining by producing stools that are softer and easier to pass.
Stop being a stationary person that people might mistake you for a pole.
Being immobile in a standing or sitting position causes the vertical organs and your intestine to push down and applies pressure in your rectal area.
Also you will want to empty your bowels as soon as you feel the need to do so.
Do not delay thus increasing pressure on the anal sphincter; relieve yourself as soon as possible.
The third effective way to prevent hemorrhoids is by changing your diet.
If your diet is mostly high in animal and protein then you may suffer from hemorrhoids.
This is due to the fact that fiber-poor diets cause the bowel to be smaller, drier and harder to pass.
So eating raw vegetables and fruits as well as brand and oatmeal definitely helps in preventing hemorrhoids.
 It helps make the stool softer and easier to pass through.