Regularly pooping

Normally I don't poop everyday.. I know this isn't good but for some reason when I was at school I did not always have to do number 2. Now I'm on vacation and working at an office. I eat basically the same way I did before and my eating habits haven't changed. But around 1 everyday after I have lunch, I always have to go to the bathroom. I know this is probably good because I am now pooping regularly but can someone explain why my poop cycle has changed ?