Nutrition: The Role of Fats and Water By Sheron S. Rowe, MSN, RN, LHRM

With the amount of nutritional information available today, many runners are attempting to improve their eating habits. In so doing, fat is often frowned upon and becomes the enemy that is severely reduced or eliminated from the daily intake of required nutrients. Additionally, when considering nutrition, hydration is often neglected. It is important for runners to understand that fat is an essential nutrient needed for overall well being and that adequate hydration is a given for runners.

A look at Fat and Water


Carbon, hydrogen, and oxygen are elements that make up fats. These are the same elements found in carbohydrates, but the ratio of oxygen to carbon and hydrogen is less in fat. The lower oxygen content in fats leads to their increased calorie content as compared to other nutrients.

Water is the principal component of the body, making up roughly 70% of the adult body weight. It is the solvent in which body salts, nutrients, and wastes are dissolved and transported. The chemical reactions that continually occur within the body mainly involve reactions that are in aqueous (water) solutions.

Fat cells contain less water than an equal volume of lean tissue. 70% of our muscles are composed of water, but this water content varies with gender, body mass, and age. The percentage of body weight composed of water is generally greater in men than women because men tend to have more lean body mass than women.

Types of fats

Researchers have discovered that Mediterranean diets consist of increased amounts of fat; however, these individuals do not have an increased risk for developing heart disease. The reason for this decreased risk stems from the fact that much of their fat comes from fish oils and olive oil which is a monounsaturated fat. Researchers have also discovered that individuals who live in areas where red meat and dairy products make up a substantial part of the diet have higher rates of heart disease. This is related to the saturated fats found in their diets.

Triglyceride is a simple fat compound consisting of three molecules of fatty acid and a glycerol. They make up most animal and vegetable fats and are the principal lipids (fatty acids and fats) in the blood.

Monounsaturated Fats
Monounsaturated fats are liquid at room temperature. They lower LDL (bad cholesterol) and raise HDL (good cholesterol) levels. Monounsaturated fats may also reduce the risk of developing certain cancers.

Polyunsaturated Fats
Polyunsaturated fats originate from plant sources and are liquid at room temperature. They are unsaturated fats that also lower LDL and raise HDL levels. These fats are known to decrease the possibility of developing heart disease.

Saturated Fats
Saturated fats, the beast of all fats, originate mostly from animals and are solid at room temperature. They are associated with both HDL and LDL. Saturated fats can aggregate and adhere to the inside of the arteries leading to plaque buildup. Individuals should make a concerted effort to reduce their saturated fat intake in order to help guard against heart disease, certain cancers, and other potential health problems.

Trans Fats
Trans fats raise LDL and lower HDL. Trans fats do not occur naturally but are created during the manufacturing process of various food items. At this time, manufacturers are not required to identify trans fats on nutrition labels, but if “shortening,” “partially hydrogenated oil,” or “hydrogenated oil” is on the label, trans fat is present in the product. In January 2006, the government will begin regulating trans fats which will mandate manufacturers to list them on nutrition labels. 




Beef fat




Coconut oil

Palm oil

Palm kernel oil

Dairy foods

Canola oil

Olive oil

Peanut oil
Sesame oil
Most nuts

 Corn oil

 Cottonseed oil

 Safflower oil

 Soybean oil

 Sunflower oil



 Fish oils

 Sesame oil

 Flaxseed oil


Why is fat important?
· Is the major source of energy.
· Aids in temperature regulation.
· Supports the cell wall within the body.
· Provides support and protection for vital organs.
· Lubricates body tissues.
· Allows body to circulate, store, and absorb fat-soluble vitamins (A, D, E, and K).
· Supplies essential fatty acid that the must obtain from the diet.
· Promotes healthy hair and skin.
· Provides a feeling of satiety after eating.

Why is water important?
· Enhances immune system.
· Aids in weight loss.
· Provides muscle tone and muscular appearance.
· Helps maintain skin.
· Metabolism requires water, leading to increase burning of calories; sleeping or running.
· Aids in maintaining body temperature.
· Removes waste products.

Athletic Performance: Can Fat and Water Affect Performance?

Runners are sometimes confused by fat consumption versus fat burning. Two prime examples of wrong ideas include 1) fats provide more calories than carbohydrates, so fats are the best source of fuel 2) running burns less fat than walking. Fats do
supply more calories per gram than carbohydrates, nevertheless, burning fat is not the preferred means of obtaining energy for the running body. It prefers carbohydrates which can be used much more efficiently than fats. Hence, runners should always eat carbohydrates before training and racing. During low intensity workouts, runners obtain greater than half of their required energy from fat while endurance runners utilize even greater amounts of fat as energy sources.

Peak performance and decreasing the risks of heat injuries requires the runner to maintain proper hydration during running. While running, the body produces increased amounts of heat which requires sweat to cool down. The body uses water to produce sweat, the sweat on the skin evaporates, and as the sweat evaporates the body is cooled. As runners sweat, they must consume increased amounts of water to keep the core temperature down. Also, adequate water is crucial for biological and chemical reactions to occur within the body to produce the required energy for running. Fluid intake should equal fluid output to maintain proper physiologic functioning. Increased thirst indicates an increase in fluid output leading to exhaustion and a decrease in performance. If individuals feel thirsty, their body is telling them it is on the way to becoming dehydrated so take precautions to avoid the ensuing complications. Then, post running, water aids in recovery by removing waste products through urination and defecation.

Fat and Water Recommendations

A very low fat diet is just as bad as a very high fat diet. Low fat diets may add to moodiness and depression. As runners, our bodies need fats as an energy source. Every five years the federal government revises the Dietary Guidelines for Americans. The 2005 updates recommend several changes related to fat. Old recommendations – keep the diet low in saturated fat and cholesterol and moderate in total fat. New recommendations – keep trans fat intake as low as possible. When manufacturers are required to include trans fats on nutrition labels, consumers will be able to monitor their daily trans fat intake. Also, individuals should get no more than 10% of their calories from saturated fat and consume no more than 300 mg of cholesterol per day. Endurance runners should include 25% of their calories from healthy types of fat.

Runners should never allow themselves to become thirsty, and the best hydration choice is usually water. When runners sweat, water and electrolytes such as potassium and sodium are lost so they should drink even if they are not thirsty. While beer is high in calories, much to a beer lover’s chagrin, it is not an appropriate source of hydration since alcohol has a diuretic and depressant effect. Additionally, soda is high in calories and has a slow absorption rate.

Water Intake Recommendations
· 2 hours prior to exercise = 16 – 24 ounces (2 – 3 cups)
· 15 – 30 minutes before exercise = 8 – 16 ounces (1 – 2 cups)
· 15 20 minutes during exercise = 4 – 8 ounces (1/2 – 1 cup)
· For every pound lost after exercise = 16 – 24 ounces (2 – 3 cups)

Hyponatremia (low sodium levels) results from either a loss of sodium containing fluids or water excess. Symptoms associated with sodium loss include irritability, apprehension, confusion, drop in blood pressure, increased heart rate, rapid and thready pulse, nausea and vomiting, dry mucous membranes, weight loss, tremors, seizures, coma, death; water excess – headache, apathy, weakness, confusion, nausea and vomiting, weight gain, increased blood pressure, muscle spasms, seizures, coma, death.

Formula: How Much Fat and Water do Runners Need?

Fats are a concentrated form of energy in which one gram of fat produces 9 calories. This is twice the amount of calories of either a carbohydrate or protein. Since fats are more difficult to metabolize, they are not the body’s ideal fuel source. An individual’s daily caloric requirement is influenced by body build, age, gender, and daily activity level. An average adult’s fat requirement is an estimated 20 to 35 calories per kilogram (1 kg = 2.2 lbs) of body weight per day. A runner would lean toward 25 – 35 % of their calories from fat. An example of converting 25% of fat into food consumption based on an 1800 calorie/day diet is: 0.25 x 1800 calorie/day diet = 450 calories of fat/day. There are 9 calories per gram of fat so divide 450 by 9 = 50 grams of fat/day.

A little water can be absorbed from the stomach, but the small intestine can absorb approximately 1 liter of water per hour. Five to ten liters of water is derived from food, drink, and digestive secretions and enter the small intestine each day while only about 0.5 liter enters the large intestine. The rest is absorbed, primarily through the upper small intestine. The large intestine absorbs 300 – 400 ml of water per day. Since one liter of water weighs 2.2 pounds, body weight change, especially sudden change, is an excellent indicator of overall fluid volume loss or gain. For example, if a person drinks 240 ml or 8 ounces (1 ounce = 30 ml) of fluid, weight gain will be 0.5 pounds.

Sports Drinks Versus Water

When running for 60 minutes or less, water alone should be sufficient for hydration. If running for greater than 60 minutes or in hot weather, electrolyte and carbohydrate replacement is necessary. Water provides straight hydration, but sports drinks will also provide the electrolytes and carbohydrates needed for adequate recovery. The carbohydrates are required for brain and muscles; sodium for water absorption and retention; water to replace sweat losses.

In conclusion, as runners, we must be aware of our nutrition and drinking habits every day and not just around our “big race.” In order to decrease the risk of adverse events, it is essential that we have a well planned stratagem for drink and food ingestion pre, during, and post endurance events.

* Sheron S. Rowe, MSN, RN, LHRM has a Masters of Science degree in nursing from the University of Central Florida and is a licensed healthcare risk manager. Currently, she is an Assistant Professor of Nursing at the Florida Hospital College of Health Science.

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