Hi Dr. Bell, I’m trying to understand the science behind Glycogen. How much can your body store? Is it true after a certain level and the stores are full, it can turn into fat? How often do you run down your Glycogen stores? Thanks!
Your body can store about 400-700 grams (1600-2800 calories) of Carbohydrate (Glycogen/Glucose), most of it in your muscles, liver, Red Blood Cells and a small amount in your kidneys, Glial Cells of your brain, White Blood Cells and for pregnant woman, in their uterus (for the exclusive use of the unborn child).
You are correct that once these organs have reached their full storage capacity, they can store no more and the excess calories will be stored as fat…for many, some place no one notices…like your belly, hips or thighs!
Actual storage capacity will vary dependent on gender, Metabolic Rate, Physical Conditioning and activity level, muscle mass, hormones, etc. You will typically deplete your glycogen stores in 12-22 hours, but they are easily replaced as you consume carbohydrates in your meal.
Depending on the Type, Intensity and Time (Volume) of your exercise, you can run yourself out of glycogen during a single exercise session. Consider that if you are training Chest, no other muscle can share their glycogen/glucose with your Pectorals, so while your pecs may run out of glucose, your Quadriceps may have a full store of glucose!
You may notice that when you get done with a hard “Leg Day” your legs are shaking, or a hard “Arm Day” your arms are shaking, this is your sign you are out of glucose in those muscles. This is the best time to eat a High Carb meal as the body is motivated to replace the glucose you lost and will store it where you need it…in your muscles!
You need to replace this glucose to repair, regenerate and adapt your targeted muscles. You also need a minimum of 120 grams of carbohydrate/day to keep your brain functioning normally.
I wish you all the best!
Dr. Jim Bell