Probably like most novices, I assumed that I may lose a little weight, or at the very least stay the same when endurance training. Especially considering my training before this was heavy lifting, and I was actively trying to gain muscle weight. But nooooo. I keep gaining weight, so far about 8 pounds. My weight doesn’t fluctuate all that much, so this is actually quite a bit for me. I knew my nutrition wasn’t at it’s best, but I didn’t think it was this bad! Apparently this is quite common for a number of reasons. This paragraph explains why I have:
“Then, because the body is not being fueled right, these athletes find themselves having uncontrollable food cravings. This can result in significant overeating or binge eating, and many times this will occur later in the day and late at night. This will lead to significant weight gain even during bouts of high-volume training.”
Other reasons include:
Building Muscle: Some people may be building up more muscle, which is denser than fat, causing increase in weight
Eating too much – gaining fat weight: Eating whatever you want because.. hey, I’m training a lot! More training means it is even more important to fuel your body right. No matter how much you are exercising, a bunch of milkshakes can still make you gain weight. Also mentioned above is the binge eating factor. Not fueling right can lead to hunger pains at night especially. Additionally, not every day is a hard training day, and you are likely more sedentary during training days when not training, whereas maybe you would be more active on a regular basis normally.
Eating too little: Your body cannot handle additional training without eating right and eating too little can cause your body to store fat.
Changes in metabolism
Muscles are storing more glycogen: When training for endurance sports, you can increase your muscle tissue capacity to store more glycogen. “The average glycogen storage capabilities for muscles of non-trained individuals is about 80 – 90 mmoles/kg… Glycogen molecules hold a substantial amount of water, 1 gram of glycogen has 2.7 grams of water with it. So, if you are consuming more carbohydrates, your body is going to contain more water… This additional water is not the same thing as water retention where excess water is held between cells; the water attached to a glycogen molecule is inside the cells, which makes it healthy. Nevertheless, it can increase your body weight by as much as 3 – 5 pounds. ” – Ace Fit Healthy Living
Once you deplete your glycogen stores of energy you will ‘hit the wall’ Energy from fat stores can fuel you for hours! You cannot run solely on energy from fat stores though. So even as your body adapts to use different sources of energy during endurance training, you will always be using your glycogen stores. The Effects of Running on Muscle Glycogen Levels explains more about glycogen storage in the muscles. So two processes are taking place 1) increasing glycogen storage capacity in the muscles, and training your body to better utilize fat storages for energy instead of only your glycogen, which is used primarily in high intensity workout. If you are training at too high intensity this is not helping your metabolism adapt to these necessary changes. Here is a good science-y article explaining “Human Kinetics: the Body’s Fuel Sources” The first article referenced above also discusses this.
Science of Glycogen Depletion
Realizing how much an effect improper nutrition was having on me and my training and negatively affecting my workouts and my body was a wake up call. I only have two weeks left, so it’s a little too late to make any significant progress in my metabolism and my training, but I can still really focus and finish out my training with proper nutrition and then be better equipped for next time. For me the biggest issues was not eating enough pre and post workout. This gave me uncontrollable food cravings. In addition to then eating poorly, it also wasn’t helping me recover as fast as I should after a workout. Grrr.