I find it dificult to have to explain myself, and defend myself when it comes to fasting, and thats why my fasts usually only end up lasting 5 days. Too many social events, where people know me as the girl who likes food. I am not overweight but I LOVE FOOD. and especially at family functions which we have a lot of I find that If i show up and don't eat anything... people would really worry. I don't necessarily like explaining to my 80 year old grandma that I am not eating for a week. Being European and having a family HUGE on eating, they would be very worried. I think fasting twice a year, once in the spring and once in the fall is good, and even better if you can keep off that weight until your next fast. It helps me be motivated at least.
Good luck to you!