For most cyclists, a good rule of thumb is to aim for 30-90g of carbs/hour if you’re exercising for more than 90 minutes, which equates to 120kcal - 360kcal/ hour. If you’re riding anywhere from 2-6 hours/day for 5-6 days/week, you may expend roughly 600-1200 kcalories (kcal)/hour on the bike so eating during your ride, and after your session is important for avoiding muscle loss, repleting glycogen stores and accelerating recovery 
. Daily calories needs for cyclists can vary from 2,000-7,000 kcal/day
(or more), depending on body weight, age, sex, and training load.