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The Dangers of Under Fueling as a Plant-based Athlete

Kayla Slater

Nov 10, 2019

One of the biggest challenges for plant-based athletes is getting adequate calories to support performance. A study in 2015 at the University of Missouri with D1 Athletes found that only 1 out of 4 athletes eat enough calories. And these athletes were not necessarily plant-based.


For plant-based athletes, it can be more challenging because foods such as non-starchy vegetables, fruits, and beans are nutrient dense low-calorie foods i.e. high in nutrients, but low in calories.

Eating an adequate amount of calories based on your age, sex, current body weight, and activity level is not just important to fuel your workouts, but also can prevent negative effects in performance and harmful effects to your body.


Here are 10 dangers of under fueling:


 1. Low energy/fatigue

How you will feel: you have a hard time getting through a hard workout or bonk during a long run.

Reasoning: Your muscles don’t have enough energy to get through your workout or run.


 2. Poor workouts and/or recovery

How you will feel: Your workouts are slower than normal and you feel more sore than usual after your workouts which impacts your next run.

Reasoning: Your muscles are lacking energy from carbohydrates which are used in your muscles as glycogen. And your body doesn’t have carbohydrates or protein to help your body recover and prevent soreness in your muscles.


 3. Increase risk of injury and/or illness

How you will feel: You may feel sick or get a stress fracture.

Reasoning: Inadequate energy can lead to hormone changes which affects your bone health.


 4. Nutrient deficiencies

How you will feel: possible low energy/fatigue

Reasoning: Common nutrient deficiencies on a plant-based diet are iron, Vitamin B12, and vitamin D. Iron is found in your blood and transports oxygen throughout your body. Vitamin B12 is involved in nerve and blood cell functions. And vitamin D is involved with bone health. When you are eating a low variety of foods and your diet is not carefully planned out, you are more at risk of these deficiencies.


 5. Hormone imbalance

How you will feel: For women, they may lose their mentrual cycle and have poor bone health which increases the risk of bone fractures.

Reasoning: A hormone imbalance can occur when you chronically avoid carbohydrates. This can be irreversible and also affect reproductive functions.


 6. Poor sleep

How you feel: You can’t sleep throughout the night or you still feel tired in the morning.

Reasoning: Poor sleep prevents adequate recovery since during rest, your body repairs itself from the stress put on it during the day.


7. Low bone density and osteoporosis

How you will feel: You may not know you have low bone density unless you get a bone scan, but are more likely to break a bone.

Reasoning: Inadequate intake of calcium and vitamin D to promote healthy bones.


 8. Reduced cardiac output

How you will feel: hypotension, fatigue, palpitations, cardiac dysrhythmias, cardiac arrests

Reasoning: your heart rate lowers to limit the amount of energy your body is using


 9. Decreased metabolism

How you will feel: Weight gain

Reasoning: when your body is chronically under fueled, your metabolism slows down


 10. Disordered eating

How you will feel: irregular eating behaviors

Reasoning: Restriction of calories can become an obsession and lead to disordered eating patterns


When health and performance issues arise when athletes are not eating enough this is known as RED-S, a term coined by the International Olympic Committee to include men and women who experience these issues.

If you think you are experiencing RED-S or experience any of the above symptoms, it is possible that you are under fueling and in certain cases, you should seek out a professional to prevent irreversible damage to your body.


Bottom line: Fueling your body is not only important for performance, but not fueling your body enough can be harmful to your body.

If you would like guidance in fueling your body right for performance and wellness, contact me to schedule an appointment.

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