Nutrition - Part 1

Female endurance athletes are constantly under pressure to be as lean as possible. Excess weight can slow down an athlete, especially in the running component of a triathlon. Losing weight is achieved through decreasing calorie intake and increasing training. As triathletes are mainly fixed in the amount of training they can do by their coaches, the (unhealthy) focus becomes on decreasing the amount of food being consumed. The main problem? Food is the fuel for performance. Not only will under eating negatively affect your performance, it can lead to developing the athlete triad.

The Athlete Triad

Decreasing one’s dietary intake can leave the body with too little energy to maintain a regular menstrual function and/or healthy bone density. The second component – amenorrhea, is defined as the cessation of a women’s menstrual cycle for more than three months. This is caused when the hypothalamus stops producing gonadotropic hormones that stimulate the release of estrogen. Without estrogen, the menstrual cycle is disrupted. The third component – osteoporosis, is defined as compromised bone strength predisposing a person to an increased risk of fracture. Low estrogen levels and poor nutrition leads to a loss of bone mineral density, which causes bones to become brittle and susceptible to fracture. As athletes are extremely active and their bones are placed under mechanical stress, the likelihood of experiencing a bone fracture is high. The most worrisome part? Peak bone mass is accumulated between the ages of 18-25 and low bone density in youth could be detrimental for a person’s bone health throughout their lifetime. Therefore, it is vital for an athlete to make sure they are consuming a variety of foods so they are getting adequate macro and micro nutrients. How many calories should you consume? That depends on your resting metabolic rate and your activity level.

Lets briefly talk about the three macronutrients.

Carbohydrates

Carbohydrates are extremely important. They provide energy, regulate blood glucose and are required for proper brain function. Glucose is stored in muscles and the liver as glycogen as energy reserves and are primarily used for short bursts of exercise. For endurance activities, glycogen is used first before the body turns to burning fat.

Healthy sources: whole-wheat bread/pasta, barley, oatmeal, quinoa, fruit

Fats

Some stored fat is essential for normal functioning. Bone marrow, organs, the central nervous system and muscles all have a small amount of fat. Fats in the central nervous system keep nerve cells firing properly and fat stored in muscles is used as fuel during endurance activities. Women need more essential fat than men due to reproductive health. They should have a minimum of 10-13% body fat, in comparison to the 2-5% men need. Body fat percentage is a far superior tool than BMI for athletes. BMI only takes into account a person’s height and weight and fails to distinguish between fat and muscles, which tend to be heavier.

Healthy sources: avocados, salmon, nuts, olive oils

Proteins

Protein is needed to build and repair muscles. They are made up of amino acids, which are used to replace old proteins in cells and tissues that have been broken down and need to be replaced. Different animal and plant sources of protein provide different types of amino acids. Sedentary adult needs 0.5-0.7 grams of protein per pound of body weight whereas athletes need 1-1.5 grams of protein per pound of body weight.

Healthy sources: seafood, poultry, eggs, beans, lean beef

Minerals and Vitamins

It is important to make sure you are eating a diet that enables you to consume an adequate amount of all the minerals and vitamins. Here are the main ones that endurance athletes tend to be lacking in.

Vitamin D and Calcium (strong bones)

Vitamin D is needed to absorb calcium. Without it, the body must take calcium from it’s stores in the skeleton which weakens existing bone and prevents the formation of new bone.

Sources: sun, supplements, fortified food products

Calcium is needed for the heart, muscles and nerves to function properly as well as for blood clotting. Inadequate calcium intake leads to the development of osteoporosis.

Sources: milk, kale, yogurt, broccoli

Iron (blood cells to carry oxygen)

Iron is required to make the oxygen carrying proteins hemoglobin and myoglobin. Hemoglobin is found in red blood cells and myoglobin is found in muscles.

Sources: red meat, seafood, dark green leafy vegetables

Potassium and Sodium (electrolytes)

Potassium is essential for normal cell function, regulation of the heartbeat and the function of muscles. An abnormal increase or decrease in potassium can affect the nervous system and increase the chance of arrhythmias. Hypokalemia can arise due to heavy sweating, vomiting and eating disorders.

Sources: sweat potato, watermelon, spinach, beets

Sodium regulates the total amount of water in the body and plays a role in critical body functions. The movement of sodium into and out of individual cells causes electrical signals for communication, which is vital in the brain, nervous system and muscles. Increased sodium occurs whenever there is excess sodium in relation to water and is caused by too little water intake or loss of water due to vomiting. Decreased sodium occurs whenever there is a relative increase in the amount of body water relative to sodium and can be caused by drinking too much water.

Sources: table salt

Remember - food can be nutritious and delicious!