This is a hard question to answer, because how long your glycogen stores last depends a lot on how intense and how long your workouts are. So the best thing to do would be to discuss it with a nutritionist
or an exercise specialist. At rest, without exercise, most baseline energy needs can be derived from metabolizing fats, and it is only when you shift to vigorous high intensity exercise that your body will need to use up the glycogen at higher rates.
If you are relatively inactive during the day, then you are probably not burning much glycogen, and will only begin to consume it when you start vigorous exercise. In theory, if you are eating balanced foods with complex carbohydrates, this glycogen should be replaced when you eat after exercise.
All of that being said, it would be best to talk to a nutritionist or to an exercise specialist if you have specific questions about your dieting and exercise plan. Again, the actual expenditures that you are interested in will depend a great deal on the intensity of your workouts, the lengths of your fasts, and the types and quantities of foods you are consuming.
All in all, the most important factor in weight loss
is "calories in, calories out" - the timing of calorie consumption is probably of less importance than the overall picture. Either way, your doctor
will be able to discuss the best options for you.