DISCLAIMER: The following article is sharing information about intermittent fasting based on my personal experiences. Even though intermittent fasting is safe for most healthy people, it may not be suitable for individuals who have specific medical conditions. Please consult with your physician or a registered dietitian or professional nutritionist before you attempt any extreme change to your current diet plan.
Intermittent fasting has gained popularity over the last few years. There has been much debate on the potential benefits and/or consequences of intermittent fasting for athletes and how it impacts performance and fitness. On January 1, 2019, I decided to adopt a lifestyle that includes intermittent fasting on a regular basis. Once my body adjusted, I gained strength, burned fat, and ultimately improved my performance as a duathlete.
So, what exactly is intermittent fasting? Simply put, intermittent fasting is a style of eating centered on when you eat versus what you eat. It’s a simple idea really: consume all your meals within a specified eating window throughout the day. More important, intermittent fasting is not a diet. I repeat, intermittent fasting is not a diet. It does not specify what foods a person should eat or what foods to avoid. Intermittent fasting does not restrict you from eating food. Intermittent fasting trains your body to prioritize burning fat rather than carbs for energy which is also a good thing if you want to get lean.
Intermittent fasting has gotten a lot of interest over the years. However, fasting in general is not new. Ancient humans often went hours or even days between meals because it was not easy to get food. Recent research suggests that periods of fasting can have some important health benefits. Along with being very effective for weight loss, some of the additional benefits of intermittent fasting include:
Reducing levels of insulin, which makes it easier for the body to use stored fat and can help to prevent Type 2 Diabetes
Lowering the “bad cholesterol” LDL (low-density lipoprotein) that collects in the walls of your blood vessels, which can increase your chances of a heart attack or stroke
Lowering your blood pressure
Stimulating human growth hormone (HGH) production that facilitates fat burning and muscle gain
Activating a process called autophagy, in which the body cleans out damaged cells, in order to regenerate newer, healthier cells
Improving brain function and having a role in protecting against Alzheimer’s disease
After performing some research and assessing my specific needs and goals, I determined that if implemented properly not only would intermittent fasting provide many general health benefits, it could also be a beneficial part of my overall training plan and improve my overall performance. I found that intermittent fasting was a great way for me to get lean without going on a crazy diet or drastically cutting my calories. In addition, intermittent fasting was also a good way for me to keep muscle mass on while getting lean. The key goal was finding a proper balance between weight management and maximizing performance.
Studies show that maximizing workout intensity in a fasted state can decrease performance so training in a fasted state is best completed at a low or moderate intensity for around 60 minutes or less. My high-intensity workouts were therefore reserved for the evenings after having my first meal and before my last meal. Since I am an age-grouper (weekend/recreational athlete) who trains with less intensity and for shorter periods of time than a top-level, elite athlete, intermittent fasting is appropriate.
I decided I would start by doing 12 hours of fasting because that seemed easiest to fit into my daily schedule. This is known as the 16:8 Method where I would consume all my daily calories within an 8-hour window and fast the other 16 hours. Basically, I could achieve this by not eating after dinner and skipping breakfast. My first meal of the day would be around 12:00 pm (noon) and I would eat my last meal of the day by 8:00 pm.
Going without food for at least 12 hours alters the way your body produces energy. The challenge was finding that sweet spot where my body was getting enough energy from the right combination of nutrients to support my workouts and recovery. Taking into consideration that dietary needs and the ability to utilize and absorb nutrients change with age, I chose whole foods and ate balanced meals that would fuel my training sessions and aid muscle recovery. I made sure to go for meals that included plenty of complex carbs and proteins while avoiding fast foods and ones that were highly processed and high sugar. My diet emphasized a lot of fruits and vegetables (I love my vegetables which are rich in vitamins, minerals, antioxidants, and fiber), whole grains, and some low-fat dairy. I was mindful of staying hydrated by drinking a lot of water. I also focused on keeping my protein intake up, making it less likely for me to lose muscle mass from fasting. If you are eating crappy (junk) food during the 8-hour feeding window, then it undermines the benefits of fasting. The goal is to have enough carbohydrates stored from previous meals or the day before so that my body regulated its fuel stores more efficiently.
I also had to learn not to be as strict while intermittent fasting in order to maintain a healthy relationship with food. If I am hungry before it’s time to break the fast (break the fast = breakfast), then I will eat my meal before 12:00 pm. At the same time if I am not hungry around the time I should eat dinner at the end of my feeding window I don’t force myself to eat. Additionally, I ate until I was comfortably full, not stuffed. Junk foods also lost some of its appeal. Overall, I developed a better understanding that some foods are better for your health than others and it made me appreciate eating real food in its most natural form more.
My specific experience from intermittent fasting over the past year has been being able to maintain a healthy body weight, having more energy, increased stamina and strength, increased concentration and focus with a clearer mind, and experiencing less stress. More important, my performance during races improved. I just simply felt great.
Ultimately, it comes down to weighing the pros and cons of intermittent fasting for yourself and deciding what works best for you and your fitness goals. Everyone is different and you should always stick to what works safely for you.
Further Reading
The ultimate beginner's guide to intermittent fasting
Intermittent Fasting and Its Effects on Athletic Performance: A Review
Calorie restriction regime enhances physical performance of trained athletes