Ok – so you don’t have time for a calorie blasting, long ride. If you are aiming to lose weight, then a short, fasted ride might have an equally beneficial effect.
Riding fasted – before breakfast – teaches your body to burn through fat – a useful skill for it to learn, especially for endurance athletes who want to be light, and don’t want to rely in constant glycogen boosting carb shots throughout their rides.
A fasted ride only needs to be around 30 minutes, and should be at a fairly low intensity. You’ll burn fat on the ride, and teach your body to be more efficient on future, long (and well fed) rides. Make sure you have a good breakfast afterwards.