Should Female Athletes Consider Intermittent Fasting?

Emily R Pappas, M.S.

Many of you have probably heard about intermittent fasting, a specific type of fasting that comes with a slew of health benefits, including weight loss. And it all sounds pretty easy.

But is it really all that healthy—especially for the female athlete?

Let’s look at how it works.

What is Intermittent Fasting?

Fasting is any period of time you go without eating. We all fast every day. Think about when you are sleeping at night—you’re not eating, you’re fasting. Soon after waking up, you eat breakfast—this is you literally “breaking the fast.”

Intermittent fasting is a bit more involved. This type of fasting allows you an “eating window,” or a set amount of time when you can eat. The “Leangains” method of intermittent fasting is the most popular form, in which you eat within a set period of 8-10 hours, and then fast the remaining 14-16 hours. For example: You may choose to eat from 12pm to 8pm, and then fast the rest of the day and night until 12pm the next day. (So, this usually means you may just skip breakfast.)

Why Try Intermittent Fasting?

There are many claims that intermittent fasting will allow your body to become more “fat adapted.” In other words, fasting will help prime your body to turn to your fat stores for energy. This can lead to fat loss and other purported benefits like blood sugar stability and increased energy.

Even more, intermittent fasting may help promote fat loss simply because you are eating LESS food overall. Decreasing the window of time in which you eat is likely to lead to you eating LESS food overall. Remember, if you are eating LESS energy than you are expending, you are in a caloric deficit. This deficit will help promote fat loss (considering it is NOT for a prolonged period of time)

While intermittent fasting can offer these positive effects in some cases, it can also be extremely detrimental, especially for athletes and active individuals.

Going too long without food can put a lot of extra stress on your body. Extra stress is counter-intuitive when your goal is to RECOVER, ADAPT, and PERFORM!

Fueling for Performance

Before you even consider WHEN you eat, you need to first focus on HOW MUCH you should eat (your caloric intake) and WHAT you should eat (your macronutrient ratios, or how much fat, protein, and carbs you should consume).

This is about 80% of what matters when it comes to fueling for both athletic performance and body aesthetics. Nutrient timing influences about 10% of our fueling priorities, while the remaining 10% comes down to food composition and supplements.

Nutrient timing considers what you eat AROUND the times you are active. We have already discussed the importance of carbohydrates as fuel before, during, and after activity to give you an idea of what we mean.

Remember that female athletes who perform at moderate to higher intensities RELY ON CARBS.

Being “fat adapted” only comes in handy when your body kicks in its aerobic energy system, which is used during longer, less intense exercise. This system is meant for slower energy output—not really ideal when we’re looking to run full speed down the court in a breakaway.

After carbs, the next important factor to consider is the timing of your protein intake.

The Power of Protein

Protein is made up of amino acids, which make up a large structural proportion of our cells, muscles, and tissues. Amino acids play crucial roles in almost all biological processes.

Protein has a few different fates when you ingest it:

Amino acids are be used as building blocks for cells, tissues, etc.
Protein is broken down and used as energy.
Amino acids are used to help your muscles grow, and prevent the breakdown of your muscles.

Our bodies offer no real protein storage, unless you consider muscle mass. But if your body needs amino acids, do you really want to break your muscle down? Muscle loss means loss in strength and performance!

So, when you ingest too much protein (or any macronutrient for that matter), your body converts it to fat. BUT when protein is converted into fat, we end up losing the important amino acids. Once they’ve been converted to fat, they cannot be converted back to amino acids.

In the case of intermittent fasting when you go without protein for too long, there will be times that your body is short on amino acids, especially the essential ones that your body can’t make.

Remember, because your body lacks storage for protein, it needs to find its amino acids somewhere else! In order for your body to create and restore its structural components (like the turnover of skin cells), it must turn to SKELETAL MUSCLE as its amino acid source.

This means MUSCLE LOSS.

This is the last thing an athlete wants. Remember, muscle is where all the POWER HAPPENS!

Less muscle means less power to SPRINT, HIT, JUMP, and KICK.

How to Fuel for Performance?

Intermittent fasting is an option for the individual who is trying to lose some body fat, as limiting the window of eating helps decrease your total caloric intake.

But when your main goal is high performance, intermittent fasting will hinder your success.

When considering performance and recovery, it’s best to make sure you are eating enough of each macronutrient for your energy levels:

Eat enough carbohydrates to fuel your activity: Around 1-3g per lb of body weight depending on your activity level.
Eat enough fats to help fuel your recovery in between hard sessions: Around 0.1-0.3 g per lb of body weight.
Eat enough protein to stimulate muscle growth and prevent muscle catabolism: Around 1g per lb of body weight.

Only once your optimal caloric intake and macronutrient ratios for your body type and activity level are set, should you then focus on the best times to eat.

Not sure what is the right amount to eat for YOU, set up a call with me and we can discuss what is the best way to fuel your body for performance!

Nutrient Timing

Nutrient timing considers WHEN you are eating certain macronutrients to help optimize your performance and recovery.

Most female athletes should eat around 4-5 meals per day to meet their energy needs for their activity level!

Here are some other tips to keep in mind:

Keep protein intake constant in each meal.

Before working out, eat carbohydrates (ideally complex carbs like bananas, peaches, sweet potatoes, and oatmeal) and low amounts of fat.

During your workout, give your muscles the fast sugar it needs to prevent you from hitting that wall! Gatorade and other liquid forms of carbohydrates are your best bet for QUICK energy!

After your training, choose a mix of simple and complex carbohydrates. This way your muscles are able to refill their glycogen stores ASAP as well as continue to energize the recovery process hours later. (think cereals, brown or white rice, white bread and jam, potatoes, pasta)

Further away from your activity, choose carbohydrates that a higher in fiber (like fruit and veggies) as well as healthy fats (nut butters, avocados, olive oil) to ensure a slower energy release

Overall, you want to be in tune with your body. You want to be eating enough calories from the appropriate macronutrients for YOU.

Intermittent fasting may be okay for sedentary individuals that are looking to lose some weight.

BUT if your goal is to optimize your performance, strength, and body composition, TIMING MATTERS!

So before you consider jumping on the new ‘fad’ of fasting, remember your goals!

For the female athlete focused on performance, intermittent fasting is only going to slow you down!