“I eat too much, drink too much, want too much. Too Much!” – Dave Matthews
My big bike ride of the season is coming up this weekend, and so I thought it was a good time to think and write about carbo loading. My ride is the Triple Bypass (TBP), which covers 120 miles and 10,000 feet of elevation gain in one day as I inch from Evergreen, Colorado to Avon, Colorado. It is a very difficult day, and certainly not one that I can do fasted. There are too many steep gradients, too much high altitude and the day is just too long. At least for now…
When I first started this experiment what I really wanted to do was be able to practice intermittent fasting most of the time, but be able to cram my muscles and liver with glycogen for the occasional big endurance event that came up. It is carbohydrates that your liver turns into glycogen in the presence of insulin, and since my non-fasting diet is mostly high fat and low carb, my glycogen stores have been habitually low for the last few months. When you ride a bicycle (or do any exercise) you burn glycogen and fat for fuel, and the ratio of which you burn is different for every individual based on a variety of factors. In general though, if you are at a low intensity you are burning more fat and if you are riding at a high intensity then you are burning mostly glycogen; I think of glycogen as jet fuel and fat as diesel fuel. The human body can store only 1,500 – 2,000 or so calories of glycogen, and has 100,000s calories of fat energy (even skinny Tour de France riders have plenty of fat energy). I will probably burn 4000-5000 calories during the TBP, much more than I will have stored, so I need to have a strategy to avoid using all my glycogen. If anyone has ever experienced “hitting the wall” or “bonking” or know someone who has, it is what happens when your body runs out of glycogen. I can tell you from personal experience it is not very fun. You get nauseous, fatigued, have no energy, cold, and most people have very negative feelings about everything. One good way to avoid running out of glycogen is to maximize your glycogen stores, or carbo load, right before the event. Another way is to keep your intensity low enough that you spend most of your time in the fat burning zone. A final way is to ingest carbohydrates that your body can easily use during the event, thus sparing your precious glycogen stores.
I am going to do what physiologists call non-depletion carbo-loading where I will try to cram my glycogen stores as full as they can be right before my ride. To properly do this I am going to need to start 2-3 days before the event. Contrary to past beliefs, you cannot fill your glycogen in one meal or even in one day. For those 2-3 days I am going to eat 80-85% carbs and 4 grams of carbs for every pound of body weight, which is a lot of carbs and calories, and going to be harder than it sounds. I am going to focus on rice, juice, bagels, yogurt, bread, oatmeal, pasta, potatoes, and waffles. I am going to stay away from high fat foods like cheese, butter and oils because they take longer to digest and do not help your glycogen. I am also going to stay away from highly refined carbs as much as possible like white bread, white rice, candy, and chips. They spike the blood sugar too fast and so they get used as fuel instead of being stored as glycogen. (As an aside those highly refined or high glycemic carbs will be prefect for during the ride where I will want a quick blood sugar spike). You might ask: “How do you know if your carbo loading is working?” As luck would have it our body has a built-in method to let us know we are loaded to the gills with glycogen. For every gram of stored carbohydrate or glycogen, your body stores 3 grams of water, so I expect that my weight will go up 3-5 pounds from my loading. This means that by glycogen loading I am also super-hydrating my body. Wow, two for the price of one and the ability to eat the foods I have been mostly avoiding for the last few months. Its win win win. I will report back next week and let you know how it went and how I felt. Wish me luck…
