[header] How to survive the world vision 40 hour famine [title] Three weeks before : [substeps] See if you are eligible to participate. If you are 12 years or under you can do the 8-hour famine, but not the 40. It is suggested that if you have any health conditions you don't participate. 
Choose to give up something else, like furniture or technology, instead. Sign up to do it, either on the website or with a group leader.