Support groups and forums

Intermittent fasting

There is a yahoo group with people on a variety of diets who share experiences and scientific information.  This is what they say about themselves: This group is devoted to intermittent fasting and its effects on physiology and health. We expect that both practitioners of intermittent fasting and scientists with an interest in the physiological effects of intermittent fasting will want to join. The founding members are both practitioners and scientists. We are interested in the idea that intermittent fasting may be a preferable way of obtaining the health benefits associated with caloric restriction (including, but not limited to, weight loss). Although we are interested in many aspects of fasting, including styles, effects and reasons to fast, this group is not about multi-day fasts, colonics, the purging of toxins or the attainment of spiritual goals. This is not the place for those who are interested in longer fasts.

Alternate Day Fasting and up day/down day diet

There's a forum for Alternate Day Fasting here.

Joint fasting support/general support

There's a facebook support group for people on either alternate day fasting or 5/2 fasting here.  There is a resources section on the group where people share recipes and information.  It's a very busy group, but there are a lot of people with experience of all the different ways of fasting/eating, so it is a good place to get answers to questions.