What to Eat to Sustain Energy During Long Distance Exercise

//What to Eat to Sustain Energy During Long Distance Exercise

What to Eat to Sustain Energy During Long Distance Exercise

I was recently asked to present a talk at my local Running Room about nutrition and it’s impact on performance, specifically long-distance running. However, the systems used by the body to sustain energy not only apply to running, but also to distance cycling, triathlons or any exercise that requires sustained energy for 10 minutes or more.

Food is the fuel we put into our bodies
to maximize energy, the fuel we get out.


In order to power physical activity, our bodies use three systems to create energy.

The Three Energy Systems 

1. The ATP Energy System

This energy system is initiated in the first 0-10 seconds of exercise. It is used for short, intense bursts of power like sprints and interval training.

2. The Anaerobic Glycolysis System

After 10 seconds, this longer endurance system kicks in and runs until about 10 minutes. This conversion is why you may feel that around the 10-12 minute mark your running or training is starting to feel more challenging. Your body, specifically your muscles, are switching over to your final, long-distance energy system.

3. The Aerobic Metabolism System

This is the system used by the body to generate energy for activities lasting longer than 10 minutes. The most efficient in terms of energy production, it is important to support this system with the right diet. A balanced intake of the right nutrients, vitamins and minerals is crucial to an enjoyable athletic experience.

As a long distance athlete, you are relying primarily on
the Aerobic Metabolism Energy System.


What are the nutrients you need to fuel this energy system? 

A variety of nutrients, minerals, vitamins and antioxidants all work together to help our body’s create energy for movement. In order to simplify the nutritional needs of the energy system, I have highlighted three main nutrient groups: Glucose, Fatty Acids and Amino Acids. Other subsidiary compounds like ATP and lactic acid are also needed, however these are created through breakdown of the main nutrients.

Glucose (a.k.a Sugar a.k.a Carbohydrates)

You may already know, there are two types of carbohydrates: Complex carbs and Simple carbs.

Complex carbs take longer to break down and be absorbed into the body. Simple carbs, on the other hand, break down more quickly and as a result, enter the blood stream quickly, spiking blood sugar levels. It is for this reason that it is recommended to avoid simple carbohydrates in daily life.

Applied to performance nutrition, both complex and simple carbohydrates
have a place and a purpose..


Complex Carbs

If you eat a wholefood, balanced diet, it’s likely that the majority of your meals contain complex carbohydrates. Examples of this include vegetables, fruit, legumes, and whole grains.

What to Eat Before a Workout?

The purpose of eating before you exercise is to prevent fatigue and to saturate your muscle’s glycogen (a.k.a stored glucose) reserves.

In order to maximize this process, consume 30-60 grams of complex carbohydrates (with a moderate to low glycemic score) about 1.5 to 2 hours before working out.

This will allow your body enough time to digest and absorb these nutrients before you perform your physical activity.

Examples of Healthy Complex Carbohydrate Options

  • 1.5 cups cooked veggies (like green beans, carrots, or broccoli) – 15-20g carbs
  • 1 cup peas – 25g carbs
  • 1 cup baked sweet potato – 40g carbs
  • 1 cup boiled/mashed sweet potato – 60g carbs
  • 1 cup cooked oatmeal – 25-30g carbs
  • 1 cup cooked quinoa – 40g carbs
  • 1 cup long grain brown rice – 45g carbs

The Perfect Meal Before a Workout

Getting enough of this macronutrient is important but eating a balanced meal that contains a variety of nutrients like minerals, vitamins and antioxidants is equally important. That’s where eating a well-rounded meal before you exercise comes in.

Combine your carbohydrates with a little bit of healthy fat to increase nutrient absorption. The perfect meal could look like a veggie quinoa power bowl.

Layer about 1/2 cup of cooked quinoa on the bottom of a bowl or plate. Top with roasted sweet potato, steamed broccoli, grated carrots, cherry tomatoes and a handful of baby spinach. Add half an avocado or a drizzle of tahini sauce for some healthy fat. And enjoy!

What to Eat During a Workout Lasting for Longer than 90 Minutes?

When exercise lasts for 90 minutes or longer, it’s important to eat during your workout, marathon or training. This is to sustain energy and to prevent a drop in blood sugar.

This is one of the few times when we actually want to eat high glycemic carbs. These quickly-absorbed carbs that would typically spike our blood sugar, provide much needed fuel as we quickly burn through our reserves.

Low blood sugar can lead to uncomfortable symptoms like nausea, weakness, dizziness and an inability to complete your workout or race. That’s why it’s important to know your body and gauge when it’s appropriate to take a quick break to refuel.

Depending on your size and the intensity of your workout, you’ll want to get about 30-60 grams of high glycemic carbohydrates during a workout. 

Examples of Healthy High Glycemic Carbohydrate Options

  • 1 cup boiled regular potato – 30g carbs
  • 1 cup steamed white rice – 45g carbs
  • 1 cup watermelon – 22g carbs
  • 1 cup pineapple – 22g carbs
  • 1 cup corn – 123g carbs
  • 1 medjool date – 18g carb

What to Eat to Promote Recovery After a Workout?

After an intense workout, we eat to replace the glycogen (stored sugar or energy) in our muscles and liver cells that has been used during exercise. We also eat to reduce cortisol levels. Cortisol hormone is the body’s response to stress. When we are stressed, cortisol levels increase. And whether we like to admit it or not, exercise is stressful to the body, especially long-distance sustained endurance type activities. We also eat to promote and aid muscle recovery.

For these reasons, high glycemic carbs are again helpful in this situation. We need to reduce cortisol levels, increase blood sugar and replenish energy in the muscle and liver cells as quickly as possible.

Immediately after your workout, aim for 30-60g of
high glycemic carbohydrates and a little bit of protein.


Omnivore options include a small piece of chicken, red meat or fish; alternatively, a great source for all eaters is a vegan protein powder like brown rice protein, hemp protein or a protein blend made of several grains.

The Perfect Meal After a Workout

A fruit smoothie with a little bit of healthy fat like full-fat coconut milk or an avocado, plus a high glycemic index fruit like pineapple or watermelon plus a scoop of protein powder will go a long way in helping to speed up recovery.

Plus it’s convenient and can be made ahead so it’s ready to drink as you finish your training session.

What About Protein?

Protein is another incredibly important nutrient when it comes to not only long-distance endurance sports, but also overall health. Protein aids in muscle recovery but it is also crucial for health skin, hormone production, digestion and more.

An appropriate serving size is 20-40g of protein per meal, depending on your size and how much your exercise. One serving is about 3 ounces of meat, which is the size of the palm of your hand and the thickness of a deck of cards. Alternatively, calculate gram quantities for vegetarian sources based on 20-40 grams, usually about 1 scoop of protein powder.

Examples of Healthy Protein Options

  • 3 ounces of chicken – 23g protein
  • 3 ounces of beef – 21g protein
  • 3 ounces of salmon – 17g protein
  • 1 egg – 6g protein
  • 1 scoop protein powder – 20-30g protein

We’ve Talked About Protein and Carbs, What About Healthy Fats?

I’m sure you know the importance of including healthy fats in your diet. What you may not know is how important this macronutrient is, specifically for endurance activities.

When it comes to long distance exercises, healthy fats increase performance by improving lung capacity. They also help to reduce excess body weight, help bring glucose and other nutrients into the cells (very important!), reduce inflammation and support healthy hormone secretions. Remember our friends cortisol and insulin, those are hormones, as is adrenaline.

You’re Eating All the Right Things But Here’s One More Crucial Piece

Water. Yes, without adequate hydration, your body can’t do all the amazing things it needs to do.

In an average 12hr period, you should be consuming 3L of water.
During exercise, this increases to 1/2 – 1 cup every 10-15min. 


This is important in preventing weakness, dizziness and low blood pressure.

Dehydration also prevents the stomach from emptying and forces your body to hold on to any partially digested food in the stomach. This can cause gas, bloating, cramping and gastrointestinal distress.

Preventing the One Thing That Could Ruin Your Race Day – GI Distress

Many people nowadays struggle with gastrointestinal (GI) tract disturbances at the best of times, but combine that with long-distance endurance exercise and you have a recipe for cramping, discomfort and even diarrhea. 

  • Reduced Blood Flow to the GI System

During physical activity, our bodies’ direct blood away from where it’s not needed, towards where it is needed. This means that as you exercise, your body draws your blood away from your GI tract, your stomach and other food-digesting organs, and moves it towards your muscles, where all the work is being done.

This leaves your GI system starved of fresh blood and can lead to cramping and bloating;
particularly if you have eaten too close to your workout and still have food remaining in your stomach.


One of the most effective ways to prevent this occurrence is by making sure you are drinking enough water. As we become dehydrated, our overall blood volume decreases. This means that not only is blood being drawn away from the GI tract, there is generally less of it to go around, this worsens the problem.

  • Stress and Anxiety

While not directly related to what you eat, stress and anxiety can have a big impact on your performance. If your stress hormone levels spike, this could be the deciding factor between a pleasant or not-so-pleasant race day experience.

In order to prevent unnecessary stress, pack everything the night before. This way you will not be rushing in the morning. Equally important is to arrive with plenty of time to check your bag and go to the washroom.

  • Fibre 

Typically, fibre is an important component of a healthy diet. It helps keep you regular, provides detoxification and keeps you full for longer after eating; however for one to two days leading up to race day and on race day, too much fibre can cause frequent trips to the bathroom. 

To prevent this, adjust your diet one to two days leading up to the race by decreasing the amount of fibre you consume. This will decrease the risk of any unwanted bowel movements at the start or during the race. Avoid high fibre bars and chose low residue foods like crackers or pretzels.

  • Fructose

While related to glucose, fructose is not absorbed in the intestines as a “ready-to-go” nutrient. Instead, fructose is absorbed more slowly in the intestines and then transported to the liver where is it converted into glucose.

This slow absorption and additional step in digestion can lead to cramping and diarrhea. To prevent this, avoid fructose on race day. 

Fructose is found in fruits but also in processed foods in the form of high fructose corn and in running gels. Instead, for an electrolyte boost, try making your own homemade gatorade.

The best way to prepare for a race is to get to know your own body. Experiment with your pre-race and race-day nutrition plan several times before the real day. This will allow you to figure out what does and does not work for you and your individual needs.

If you would like further insight into fuelling your body for exercise and beyond, please email Kate regarding 1-on-1 nutritional counselling services.




About the Author:

Kate Ortak is Certified Holistic Nutritionist and health writer. She is the founder of KO Nutrition Wellness. She focuses on clean living, healthy eating and detoxifying naturally through the Slim Down Detox program, her hands-on cooking classes, private nutritional counselling and her all-natural beauty line.

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