I've just completed a 4-day water fast. I do not have a weight issues. I wanted to boost my immune system. I was amused by the friends who warned me that fasting could be dangerous and therefore I had to be careful, take it easy etc. Alas few people show the same amount of concern or are willing to advise friends who are eating too much sugar-loaded ready meals and sugar-loaded fizzy drinks to be careful because they are ruining their health!