There are two popular forms of Intermittent Fasting (IF) - the 16:8 method and the 5:2 method. The former involves consuming your daily caloric requirements in the span of 8 hours, and fasting for the remaining 16. The latter involves consuming your required calories (about 2000/day on average) for 5 days a week, and consuming 500 calories on the other 2 days of that week. Typically, a 16:8 IF Method means eating an early dinner and skipping breakfast. To incorporate a 16:8 IF into a workout routine such as cycling, would mean to train in the morning without eating and complete your workout in a carbohydrate-deprived state, relying on fat stores for fuel instead.