As humans we get energy from calories in food. When speaking of the energy found in foods, the unit of measure is called a kilocalorie or 1000 calories. There are six essential nutrients the body needs in order to survive. They are carbohydrates, fats, proteins, vitamins, minerals, and water. Each nutrient has a specific function and is used by the body differently.
Carbohydrates: Typically known as carbs, this nutrient's basic building block is a sugar molecule. Carbohydrates are the body's main source of energy and provide 4 calories for every one gram. It is recommended that 55-60% of a daily diet should consist of carbohydrates. There are two types of carbohydrates: simple sugars and complex carbohydrates.
Simple sugars are made of one or two sugar molecules and complex carbohydrates, also known as starches and fibers, are made of long chains of sugar molecules. When carbohydrate is ingested, the body breaks it down into a single sugar molecule called glucose. It will then enter the blood for distribution to working muscles, the nervous system, or other organs in need.
If there is an excess of glucose, the body will store it. Glucose can be stored in the liver, muscles, or it can be converted to fat and stored in adipose tissue, otherwise known as fat cells. The body will fill up the liver and muscle reserves first. When those are full it will convert excess glucose to fat and store it in the adipose tissue.
Simple sugars are found in foods such as juices, honey, jams, candy, and enriched processed foods such as white bread and pasta. These carbohydrates are quickly digested and dispersed in the blood. For this reason, the body can experience high spikes in blood glucose which may cause a quick burst of energy. Following this quick burst of energy, the glucose content in the blood can drop dramatically and one may feel hungry or fatigued within a few hours after consuming. Simple sugars should be eaten in moderation.
Complex carbohydrates are found in foods such as whole wheat bread, brown rice, wheat crackers, oatmeal, vegetables, and whole grains. This type of carbohydrate should formulate 55-60% of daily carbohydrate intake. Complex carbohydrates take longer for the body to digest and distribute to the blood, therefore avoiding the blood glucose spikes experienced when eating simple sugars.
The rebirth of the low-carbohydrate diet has many people confused as to what to eat. Low-carbohydrate diets can be very dangerous for a variety of reasons. First, carbohydrate is the preferred source of energy when exercising at a high intensity and supplies 40% of energy at rest. When carbohydrate is low, the body will start depleting its liver and muscle glucose stores. When those are empty and the body has no other means of getting energy quickly, it will start depleting its fat stores. The body will also believe it is being starved and will lower its metabolic rate.
As soon as carbohydrates are introduced back into the diet the body will start replacing all of the stores it used up just in case it experiences this starvation period again. Weight gain is inevitable. Other complications of low-carbohydrate diets are water loss, electrolyte imbalance, decreased muscle mass, increased blood fat/cholesterol and liver fat, and decreased bone calcium. For these reasons it is better to eat a balanced diet and exercise daily for weight loss.
Fats: Yes, fats are essential to the body! You can get the most energy from fats which provide 9 calories per gram. The basic building blocks of fat are lipids. There are two types of fat found in food and in the body: triglycerides and cholesterol. Triglycerides can be classified as saturated or unsaturated. Saturated fats come from animal products and some oils and are solid at room temperature. Foods high in saturated fat should be avoided! Unsaturated fats come from plant substances and are liquid at room temperature.
Unsaturated fats consumed in adequate amounts are healthy and can lead to health benefits.
Cholesterol is a waxy fat substance found in animal products. This type of fat is not essential because the body produces cholesterol in the liver. High levels of blood cholesterol can lead to coronary heart disease. A healthy cholesterol count for the average person is below 200 mg/dl.
Fats do more than just provide energy. They enhance the flavor of food and contribute to feelings of satiety during and following a meal. The body needs controlled amounts of fat because it helps protect vital organs and insulates the body from cold environments. It also assists in cell membrane formation and absorption of fat-soluble vitamins. The average person's diet should consist of 15-20% fat. Dietary fat is found in animal products such as meat, eggs, and dairy products as well as plant products such as nuts, seeds and grains.
Proteins: Proteins are formed by long chains of amino acids. They provide 4 calories per gram. The average diet should consist of 15-20% protein depending on activity levels. There are 20 amino acids in all; 8 are essential. Proteins are classified as complete or incomplete. Complete proteins come from animal and soy products. They are labeled complete because they contain all 8 essential amino acids. Incomplete proteins come from plant products. These proteins are missing one of more of the 8 essential amino acids.
It is important to consume adequate amounts of protein when exercising. Protein is a structural basis for many tissues in the body, particularly muscle tissue. Protein helps synthesize muscle tissue when stressed or damaged. There is a misconception, that when participating in heavy weight lifting, protein levels need to be significantly increased. Research has not concluded this to be true although it has proved that recommended protein intake for an average person is insufficient for those who participate in strenuous exercise or lifting.
If excess amounts of protein are consumed and not used by the body, they will be converted into carbohydrates or fats and stored. It is suggested that regular exercisers should consume 1.5-1.8 grams of protein per kilogram of body weight for optimum tissue synthesis.
Vitamins: Vitamins are organic substances that are essential for proper function of body systems. They help facilitate certain chemical reactions in cells. Vitamins aid in functions such as digestion, muscle movement, energy production, and tissue repair. They are an essential nutrient because the body does not produce enough to meet its demands. We obtain vitamins from diet and supplements. There are two types of vitamins:
fat-soluble and water-soluble. Fat-soluble vitamins dissolve in fat before the body absorbs them into the blood stream, are excreted slowly, and are stored in the liver. Water-soluble vitamins dissolve in water, are not stored, and are frequently excreted through urination. This type of vitamin needs regular replacement through diet.
Since fat-soluble vitamins are stored, excess amounts can be toxic to the body. A balanced diet should supply the recommended daily allowance for each vitamin in otherwise healthy individuals. Vitamin supplements that contain mega doses of fat-soluble vitamins may lead to toxicity. Fat-soluble vitamins are A, D, E, and K. Water-soluble vitamins are the B-complex vitamins and vitamin C.
Minerals: Minerals are inorganic substances that also aid in body functions and are found in teeth, bones, and nails. Some common minerals are calcium, iron, magnesium, and phosphorus.
Calcium is used in the body for bone formation, nerve impulse transmission, and muscle contraction. A depletion of calcium over time can lead to osteoporosis, a weakening of the bones. Calcium is found in dairy products and dark green leafy products.
Iron is important for oxygen transportation and utilization. The majority of iron is used to form hemoglobin which carries oxygen in the blood. Hemoglobin resides in red blood cells. Iron is a common mineral deficiency in the American diet. It is more common for women than men to have an iron insufficiency because a large amount of iron is lost during the monthly menstruation.
When iron is low in the body it can cause anemia, a decreased amount of red blood cells. Tiredness, inability to regulate body temperature, and pale skin are some symptoms caused by low iron levels. Iron is found is dark green leafy vegetables, meat, poultry, and fish.
Magnesium helps facilitate protein synthesis, muscle contraction, and the breakdown of glucose into energy. Fifty to sixty percent of magnesium is stored in the bones. A magnesium deficiency can lead to muscle weakness and soreness. It is found in whole-grain products, milk, yogurt, fruits and vegetables.
Phosphorus also aids in bone formation. Eighty to ninety percent of phosphorus combines with calcium to form calcium phosphate which is used in the development of bones and teeth. Phosphate is also used in cell membrane formation. A deficiency in phosphate can lead to the same symptoms as calcium but rarely occurs. It is found in all protein products.
Water: Water is a key essential to a healthy body. The body is roughly 60% water! An average person needs about 8 cups of water per day depending on their activity levels. For most people drinking .5-1 cup every 10 minutes of intense exercise will replace the amount of water lost in sweat. It is essential that water is replaced when exercising because it is a key ingredient in keeping body temperature cool when the environment temperature is elevated.
Typically, the thirst mechanism is not a good sign to indicate when the body needs water. This mechanism is activated when dehydration has already occurred. Dehydration can lead to heat illnesses such as heat exhaustion and heat stroke because of the inability to sweat. It also can cause electrolyte imbalance and malfunction of the body systems. This can lead to decreases in energy and performance.
Water is found in vegetables, fruits, and other liquids. For exercise lasting less than 60 minutes in duration, 16 oz. of fluid is adequate to hydrate the body before activity. This should be consumed 1-2 hours prior to exercise. Six to eight ounces should be consumed during exercise every 10-15 minutes. Hydration post exercise should occur within 24 hours of exercise. Drink enough water to replace body weight lost during exercise. This figures to be 24 ounces to every 16 ounces lost.
Nutrition is a key factor in maintaining a healthy body along with regular exercise. It is important to eat a variety of foods for balance and to make sure that all essential nutrients are available for the body. The body will function better when its needs are met!