I had heard about intermittent fasting (IF) for many years from people like Robb Wolf, my former coach Scott Hagnas, and Martin Berkhan, but I had never tried it myself. Why? I abstained from long periods of fasting because my primary goal has been performance and not aesthetics. Let me explain further.

How it works?

Fasting is when you are not eating/drinking calories. That means your body is working to breakdown food in your gut for energy. The theory is that instead of utilizing food that you have recently eaten, your body starts breaking down energy stores within the body to fuel itself. There are different methods to fasting. The 16/8 Method involves fasting every day for 14-16 hours, and restricting your daily "eating window" to 8-10 hours. Within the eating window, you can fit in 2, 3 or more meals.

What does the research say?

Intermittent fasting may drive weight loss by lowering insulin levels.

The body breaks down carbohydrate into glucose, which cells use for energy or convert into fat and store for later use. Insulin is a hormone that allows cells to take in glucose.

Insulin levels drop when a person is not consuming food. During a period of fasting, it is possible that decreasing insulin levels causes cells to release their glucose stores as energy.

Repeating this process regularly, as with intermittent fasting, may lead to weight loss.

Intermittent fasting can also lead to the consumption of fewer calories overall, which may also contribute to weight loss.

do I prescribe it to clients?

In my experience in prescribing IF for athletes, it is often easier to make things binary: EAT or DON’T EAT.

For individuals who have a hard time with snacking, this tends to be a solid option. You are allowed to eat during your window, then that window is closed and you are not eating excess calories.

If an individual has appetite, IF is a great option. However there are some instances where I don’t choose IF:

Why I wouldn’t choose IF:

  1. The individual doesn’t have an appetite: If the client doesn’t eat much as is, restricting feeding tends to be a bad option as it continues to drive down natural thyroid activity and up-regulates stress responses (adrenaline and cortisol). The increase in stress hormones is counter to the clients main goal: body composition changes. For these individuals I usually recommend quality foods and getting their appetite going first because considering IF.

  2. The individual has performance goals: If an athletes goals are to get bigger, faster, and stronger, then eating enough quality calories is very important. It is 1. difficult to consume the necessary calories during the feeding window and 2. challenging to put quality training sessions around the feeding window. I would rather have the athlete be able to consume ample calories throughout the day than to restrict their eating.

my experience

I decided to restrict my feeding window to 8 hours at least 6 days a week (the weekend I allowed some variance to reduce stress and allow me to eat out with my girlfriend). Typically, I would break my fast at 8am (breakfast) and begin my fast at 4pm. My breakfast was usually around 1,000 calories (eggs, egg whites, bacon, 2 cups of potatoes or cream of rice cereal, and 2 cups veggies). Lunch was 12oz meat (usually chicken sausage or beef), 2 cups rice (white), and more veggies. I would try and sneak in another snack (peanut butter and jelly on a rice cake), and then I would begin my fast.

I was feeling light and lean, especially in the beginning. As I got later into the day, I started to feel tired and sleepy. That’s not a bad thing since the body should be getting tired toward the end of the day, preparing for sleep. However, I wasn’t winding down during that time. Often, I was ramping up! I was teaching classes at the Crossfit I own or coaching lacrosse games until 9pm. So during my fasting window I was putting a tremendous amount of stress on my body for fuel. My body responded by eating through the fat stores on my body, and I dropped about five pounds. My midsection leaned out and my love handles and back fat started to dissipate.

On top of the coaching and instructing, I was also hitting Crossfit classes 4-5x per week (1 hour of a mix of strength training and mixed conditioning.


I never felt tired during workouts, but I didn’t feel an extra boost either. I believe there was not negatives or positives when it came to my training.

However, things went south about six weeks in to my IF experience. I hit a workout on Wednesday afternoon, and I felt excessively run down with a sore throat for the next four days. By Sunday night, I had a fever and chills like I hadn’t had in a decade. I was sick for a week with a sinus infection and was hocking up loogies for the next month.

Overall, I leaned out and my sleep improved marginally, though I felt wired upon waking, like I was in a stressed state. My workouts and performance had no improvement but no drop off. I ended up getting sick worse than I have in quite some time.

Would i do it again, and what would i do different?

I would only do it again if I didn’t have such a high activity level. Because of my profession and lifestyle, I need more readily available calories. The six weeks I was hitting the fasting, I was putting too much stress on my body for calories and it just couldn’t keep up. This ran down my immune system and caused me to get sick.

I would get a baseline of calories I actually burn throughout a typical day and plot that off what I was taking in.

Since I don’t want to have my performance drop off too much, and aesthetics aren’t my only concern, fasting isn’t for me right now. If that changes, I would consider IF as it did lean me out quickly.