Fundamentals of Human Nutrition/Diet and Fitness
14.3 Diet and Fitness
Diet and fitness work hand in hand meaning that in order to maximize the potential of one you must work on perfecting the other as well. Someone with a bad diet would not be able to achieve a ‘fit” or “in shape” body and conversely someone who trains hard and devotes a lot of time to training would be weak without a stable diet to support them. Currently the general trend of society is towards an un-fit lifestyle that consists of terrible eating habits and neglect towards key recommendations in regards to nutrient intakes. In order to have good fitness one needs to be physically active. Physical activity can produce long-term health benefits such as: reduce fat, lower risk of heart disease, strengthen bones, improve mental health, etc. (1, 2) In order to have the proper energy supply for physical activity, one needs to keep their diet in check. This means reaching all the proper recommended values of each nutrient for your body type and age. Eating at the correct times of day, this means eating before the times of increased physical activity. However, eating too much before you exercise can cause you to fee slow and sluggish. (3) Some simple suggestions in order to keep your diet and physical activity in sync would be to drink plenty of fluids, eat carbohydrates and protein to help your muscles recover, stray away from large meals and instead eat smaller meals more frequently. (3) One way to increase your physical activity and your overall fitness would be to make physical activity a part of your life. (2) This means to work in movement and activity into your everyday schedule. This could mean to take the stair instead of elevator, bike to your destination or even join a gym to take fitness classes. With this increased activity you will need to make sure that you are meeting your proper amount of kilocalories to supply energy to fulfill this activities. Always keep in mind that without the proper amount of calories, you will feel weak and unable to perform. This is different for everybody so in order to truly find out what is the correct balance of diet and activity you will have to test it out for yourself. Food choices dictate your overall health and well-being. Diet can determine how you feel at this moment and also in the future. A good diet will always go hand in hand with an optimal amount of physical activity or fitness.
Sources: (1) President's Council on Fitness, Sports & Nutrition. (n.d.). Retrieved November 30, 2015, from http://www.fitness.gov/be-active/why-is-it-important/ (2) Be Active Your Way. (n.d.). Retrieved November 30, 2015, from http://health.gov/paguidelines/pdf/adultguide.pdf (3) Fitness. (n.d.). Retrieved November 30, 2015, from http://www.mayoclinic.org/exercise/ART-20045506?p=1
14.3.1 Carbohydrate loading
Carbohydrate loading is a diet strategy that involves greatly increasing carbohydrate intake before high intensity physical activity. It was first developed in the late 1960s and was made up of a 3-4 day depletion phase followed by 3-4 day loading phase (RSM-AH, 2012). During the depletion phase the athlete would engage in hard training with very low carbohydrate intake. It was believed that this would stimulate the enzyme glucose synthase, but with further research it was discovered that the depletion phase is not required for carbohydrate loading to have its desired effect. The current method of carbohydrate loading involves only part two, the loading phase. The loading phase involves a high carbohydrate diet of about 7-12g/kg of body weight and is usually done for a few days before a high intensity athletic event. The goal is to increase the body’s fuel storage in the muscles, and as a result improve athletic performance (Mayo Clinic Staff, 2013). Carbohydrate loading is usually coupled with reducing physical activity for 1–4 days and resting up for the high-intensity endurance athletic event. As a result of the increased fuel storage, the athlete will have more energy and experience less fatigue during the completion of the high-intensity athletic event. Carbohydrate loading is only necessary for moderate to high intensity endurance events that last more than 90 minutes. Marathon runners, endurance swimmers, long distance triathletes, cross-country skiers, and cyclists are the athletes that benefit the most from carbohydrate loading. Most other athletes do not need to do carbohydrate loading, as the body can use its existing energy storage for most recreational activity. For most other athletes as long as their diet is 50% or more carbohydrates, they will not need carbohydrate loading and can participate and excel in athletic events. The most common mistakes made by athletes participating in carbohydrate loading can be attributed to not coupling it with an exercise taper, failing to eat enough carbohydrates, consuming too much fiber, fear of weight gain, and eating too many high fat foods. Since athletes are used to continuous training, they can find it difficult to cut back on training for 1–4 days. Carbohydrate loading requires athletes to reduce fiber intake to avoid digestive discomfort. During carbohydrate loading athletes can gain about 2 kg in body mass, an athlete’s fear of gaining excess weight can prevent them from doing carbohydrate loading properly (AIS). It is also important to make sure that carbohydrate loading is made up of high carbohydrate and low fat foods. Some of the risks involved with carbohydrate loading are weight gain, blood sugar changes, and stomach upset. Therefore, athletes, especially diabetics, should consult with their physician before engaging in carbohydrate loading.
Advice Given to Athletes on Carbohydrate Loading Has Changed since the 1960's. (n.d.). Retrieved from http://www.gssiweb.org/video/carbohydrate-loading-has-been-used-since-the-1960s-has-anything-changed-in-the-advice-given-to-athletes- Australian Sports Commission | AIS. (n.d.). Retrieved from http://www.ausport.gov.au/ais/nutrition/factsheets/competition_and_training/carbohydrate_loading Carbohydrate Loading for Endurance Athletes. (2012, May 23). Retrieved from http://regionalsportsmedicine.org/sports-medicine/carbohydrate-loading-for-endurance-athletes/ Nutrition and healthy eating. (2013, January 23). Retrieved from http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/carbohydrate-loading/art-20048518
14.3.3 Micro-nutrient needs
Micronutrients consist of fat-soluble vitamins, water-soluble vitamins, and trace minerals. Micronutrients are essential to our diets because they help with the transportation of oxygen and energy release during daily activities. During strenuous exercise, energy is turned over into the skeletal muscles meaning there is a greater need for micronutrients to provide more energy (Maughan, 1999). Athletes need their daily nutrients because of how much energy they expend during exercise. Many athletes believe the common myth that taking vitamin and mineral supplements before a competition will enhance their performance (Whitney & Rolfes, 2014). In reality, vitamin and minerals require a few days before they can function in helping the body’s energy. A typical athlete who eats nutrient-rich foods will gain all the necessary micronutrients in their diet. In Maughan’s article, he stated “Vitamin supplementation is generally unnecessary” (Maughan, 1999). Today researchers can agree that those who suffer from any deficiencies may take supplements to help with the deficiency but not to increase performance (Whitney & Rolfes, 2014). Further research about the benefits of taking supplements is still being performed today.
Water-soluble vitamins are most involved in energy metabolism in the body (Maughan, 1999). Athletes should pay attention to their intake of water-soluble vitamins in order to have a proper amount of energy. Important water-soluble vitamins that are expended during exercise include folate, riboflavin, niacin, thiamin and the B vitamins. If an athlete chooses to use supplements, then they may want to focus on supplements that will provide the necessary amounts of each of these micronutrients.
Vitamin E and Iron
Some athletes may want to pay attention to their Vitamin E and Iron intakes due to the higher chances for deficiency of these nutrients. Exercises that require a lot of energy usually cause the muscles to consume more oxygen, which in turn increases free radicals in the body. Antioxidants, specifically Vitamin E, help defend cells against any free radical damage that may occur. When free radicals are being produced more than antioxidants, oxidative stress will occur (Lobo et al., 2010). Oxidative stress can result in the damage of lipids, nucleic acids, and proteins which may interfere with DNA formation and the Electron Transport Chain. Vitamin E is necessary to reduce the chances of important cells being damaged in the body. Another micronutrient that needs attention is iron. Many young, active women are vulnerable to iron deficiency because the muscles absorb iron during strenuous exercise (Whitney & Rolfes, 2014). Women also lose a decent amount of iron through menstruation. Iron deficiencies can cause anemia which can result in an individual becoming more easily worn out during exercise. Individuals with an iron deficiency may be prescribed supplementation if needed, but many can obtain the necessary amounts of iron through a diet high in meats (especially red meat).
Lobo, V., Patil, A., Phatak, A., & Chandra, N. (2010). Free radicals, antioxidants and functional foods: Impact on human health. Pharmacognosy Reviews, 4(8), 118–126. http://doi.org/10.4103/0973-7847.70902
Maughan, R. J. (1999). Role of micronutrients in sport and physical activity. British Medical Bulletin, 55 (3), 683-690. http://bmb.oxfordjournals.org/
Whitney, E. N., Rolfes S. R. (2016). Fitness: Physical Activity, Nutrients, and Body Adaptations.Understanding Nutrition. (pp. 455–462). Stamford, CT: Cengage Learning
Anemia is a condition that occurs when there is some malfunction in regards to a person’s hemoglobin – they either don’t produce enough of it, or any at all, their hemoglobin is ineffective in some aspect, or the body breaks it down too quickly. The result of all of these scenarios is that the body does not receive enough oxygen to its tissues. (1, 4) Although there are several causes of anemia, the leading cause is due to iron deficiency, which is also the most common nutrient deficiency worldwide. (2) According to the National Heart, Lung, and Blood Institute, anemia is the most frequently occurring blood disorder, affecting greater than 3 million Americans. (3)
There are several symptoms indicative of anemia, these include: • Weakness/feeling fatigued • Dizziness • Headaches • Difficulty breathing • Pounding or “whooshing” sound in ears • Pale or yellow appearance • Feeling cold • Cognitive problems • Fast or irregular heartbeat • Chest pain (3, 4)
Common types of anemia
There are several types of anemia that can occur as a result of different causes. Iron-deficiency anemia – As mentioned, iron-deficiency anemia is the most commonly occurring form. As the name suggests, this form anemia occurs when there isn’t enough iron in the body. Iron is necessary for the production of hemoglobin for red blood cells. This form of anemia is almost always caused by blood loss or the inadequate absorption of iron. Vitamin-deficiency anemia – Vitamin-deficiency anemia occurs when there are low levels of vitamin B12 or folic acid, both of which are essential components of healthy red blood cells. The result of this form of anemia is decreased red blood cell production as a result of poor absorption or inadequate intake of these vitamins. Anemia due to chronic disease – Certain types of diseases (like HIV/AIDS, rheumatoid arthritis, Crohn’s disease, bone marrow diseases, etc.) can result in anemia in those affected by them because the disease may alter the body’s ability to make red blood cells. For example, some patients with kidney disease may find themselves in an anemic state as the kidneys are affected in such a way that they do not make enough of the erythropoietin hormone, which signals bone marrow to make more red blood cells. Thus, without sufficient amounts of this hormone, the body lacks red blood cells. Chemotherapy for cancers also causes the same effect. Aplastic anemia – While relatively rare, aplastic anemia occurs when the body ceases to make enough red blood cells, or any red blood cells. Viral infections, autoimmune diseases, drugs, and exposure to toxic chemicals cause this type of anemia. Hemolytic anemia – Hemolytic anemia arises when red blood cells are broken up in the bloodstream or spleen. This breakdown occurs faster than the rate at which bone marrow is able to reproduce the red blood cells. Certain blood diseases, congenital abnormalities, infections, or mechanical causes (such as leaky heart valves or aneurysms) are commonly the cause of hemolytic anemia. Sickle cell anemia – This form of anemia occurs when red blood cells assume an abnormal, crescent shape. This unusual shape causes the cells to become rigid and stick together in the cells, causing clogs, commonly in small blood vessels – which can be fatal to those affected. Sickle cell anemia is an inherited, genetic disorder occurring in African Americans. (1, 3, 4)
The treatment for anemia depends on the type of anemia diagnosed by the doctor. Iron- and vitamin-deficiency anemia may be treated (and prevented) by a change of diet to include foods higher in those components. Since iron-deficiency anemia may also be caused by blood loss somewhere in the body, the doctor may perform more extensive tests to investigate this and treat accordingly. For anemia caused by chronic disease and hemolytic anemia, management/treatment of the disease, or cause, will likely improve the effects of anemia. Aplastic anemia stems from bone marrow malfunctioning so this treatment may include medications or blood transfusions to try to manage the disorder. Sickle cell anemia doesn’t seem to have any current treatment; rather one with this disorder must adjust their lifestyle in such a way to diminish the risks associated. (1, 2, 3, 4)
1. Anemia. (2014, August 19). Mayo Clinic. Retrieved from http://www.mayoclinic.org/diseases-conditions/anemia/basics/definition/con-20026209
2. Iron Deficiency Anemia. (2009). Iron Disorders Institute. Retrieved from http://www.irondisorders.org/iron-deficiency-anemia
3. Anemia. American Society of Hematology. Retrieved from http://www.hematology.org/Patients/Anemia/
4. Diseases and Conditions: Anemia. (2014). Cleveland Clinic. Retrieved from http://my.clevelandclinic.org/health/diseases_conditions/hic_Anemia
Diet and Fitness Intense Physical Activity on Female Athletes Over the last several decades, it has become more common for women to participate in collegiate, professional, and competitive sports. Being such an athlete requires intense training, extensive physical strain on the body, as well as in some cases restricted diets. Although this can be taxing on any athlete, many studies show there are specific health risks for female athletes specifically competing at this level. Who is at Risk? Female athletes that train intensely and or do not get all of the nutrients they burn throughout their day. Women involved in sports dependent on low body mass and minimum body fat typically have more health problems (Fruth, Worrell, 1995). Female cyclists, ballet dancers, cyclists, gymnasts, and swimmers are the sports that require intense endurance training and low body weight. Also women that are genetically predisposed to have certain health conditions can have a higher risk of those conditions coming to fruition. An individual’s body that produces little estrogen regardless of activity level is also associated with having more health risks as a result of intense training (Fruth, Worrell, 1995). Health Risks for Female Athletes Of the negative affects of intense training, a common condition that can arise is athletic amenorrhea, also known as hypothalamic hypogonadism. This is a condition where the individual’s monthly menstruation has ceased for anywhere from 3 to 12 months straight. Though this may seem like a positive affect of physical activity, it can have long-term detriments. Women with this condition have a decrease in bone density and may even never be able to achieve their peak bone density. This is a slow and subtle process leading to premature osteoporosis (Clark, 1997). This makes it difficult to catch and treat before injuries occur. Athletes with amenorrhea are also at a three times greater risk for stress fractures as a result of the decrease in their bone density (Clark, 1997). Also women who have amenorrhea and participate in extreme amounts of training are extremely likely to have low amounts of estradiol in their bodies. Estradiol is the main form of the hormone estrogen in females’ bloodstreams. These levels are almost always too low because adipose fat tissue is a place where this hormone is converted from androgens. Since these individuals have such low amounts of body fat these hormones are extremely lower than normal (Fruth, Worrell, 1995). As well as decreasing bone density and causing amenorrhea, intense physical activity has been associated with infertility. There was a study done in 1979 that compared the ovulations of runner athletes with those of a control group. Only 50%
of the runner athletes ovulated at all, compared to the 83% of the control group that did (Dale, 1979). This can be a major health concern for women of childbearing age who wish to be pregnant. Treatment Most sources agree that either eating a bit more or exercising a bit less will reverse some of the affects of intense physical activity and inadequate diets. Diets are very important for individuals who expend so many nutrients, such as endurance athletes. It is beneficial to eat 0.5- 0.75 grams of additional protein each day or decrease activity level by 5-15% (Clark, 2001). Also gaining 1–2 kg of body weight can reverse amenorrhea and improve bone health. However, these recommendations are often hard to follow, as many athletes don’t want to jeopardize their athletic performance or appearance. References Fruth, S. & Worrell, T. (1995). Factors Associated With Menstrual Irregularities and Decreased Bone Mineral Density in Female Athletes. Journal of Orthopaedic & Sports Physical Therapy, 22(1), 26-38. doi: 10.2519/jospt.1918.104.22.168 Clark, N. (1997). Nutrition Advice for Active Women with Amenorrhea. SportsMedicine Brookline, Brookline. Retrieved from: https://www.cals.ncsu.edu/course/ntr301/AMNRRHA.HTM Warren, M., & Perlroth, N. (2001). Hormones and Sport: The Effects of Intense Exercise on the Female Reproductive System. Journal of Endocrinology, 170(1), 3-11. doi: 0022- 0795/01/0170-003 Dale, E., Gerlach, D., & Wilhite, A. (1979). Menstrual Dysfunction in Distance Runners. The American College of Obstetricians and Gynecologists. 54(1). doi: http://journals.lww.com/greenjournal/Abstract/1979/07000/Menstrual_Dysfuncti on_in_Distance_Runners.13.aspx
14.3.5 Fluid and Electrolytes to Support Activity Added by Emma Hovey
Due to a high metabolic rate, the sweat level of athletes is high (Fischer-Colbrie, 2015). If exercise is frequent and intense, athletes need to be consuming appropriate liquids to compromise for the lost fluids. The lack of fluid intake can lead to dehydration. Dehydration can not only impair an athlete’s performance, but also have serious health implications. Hydration is an important way to maintain endurance levels and keep the body at equilibrium. Dehydration impacts a workout by leading to lower performance levels, increases perceived exertion, and can cause an individual fatigue. Not only does the overall performance of an athlete decline when dehydration, but post-exercise recovery suffers as well. When deprived of fluids, the body has to work harder to repair muscle tissues and remove bloodstream waste.
Fluid and Electrolyte Balance
Physical exercise increases the contraction of skeletal muscles. This action raises the body’s total metabolism to function at least five times the rate of an individual’s resting heart rate. The majority of this energy is given off by heat. In particularly warm environments, body fluids may be lost through sweat, cooling off the body, therefore aiding in equilibrium (Mountain&Sawka, 2000). Electrolytes, along with water, are lost in sweat. Sodium chloride is the major electrolyte lost in sweat. The minor electrolytes lost are calcium, potassium, and magnesium. The balance of these minerals lost via sweat varies on the individual. During exercise, it is important rehydrate the body with fluids lost by sweating. Thirst is a poor indicator of dehydration. Once an individual experiences the sensation, they have lost up to two percent of their body fluid.
Replacement of Lost Fluids and Electrolytes'
Replacing electrolytes and fluids lost during exercise is critical for an athlete’s performance and recovery. Specific electrolytes are time sensitive, being better absorbed before, during, or after exercise (Dolan, n.d.). Electrolytes are used to maintain fluid balance in the human body. They play a role in conducting electrical activity and are charged ions. Having a proper balance of electrolytes allows the body to not only regulate the balance of fluids, but muscle and neural activity as well. The main organs assisting in fluid regularity are the kidneys. They balance electrolyte levels by conserving or excreting electrolytes. Due to the polarity of water molecules, they follow the locations in the body that are highly concentrated with electrolytes. Specific foods help to replace specific electrolytes. A deficiency in sodium, for example, may manifest as a muscle cramp. Food sources to replace this lost electrolyte range from a dill pickle to a glass of tomato juice.
1. Fischer-Colbrie, M. (2015). Athletes, Sweat, and Why You Need Electrolytes. Retrieved April, 2017, from http://blog.bridgeathletic.com/athletes-sweat-and-why-you-need-electrolytes-bridgeathletic 2. Sawka, M. N., & Montain, S. J. (2000). Fluid and electrolyte supplementation for exercise heat stress. Retrieved April, 2017, from http://ajcn.nutrition.org/content/72/2/564s.full.pdf html 3. Dolan. (n.d.). Electrolytes: Understanding Replacement Options. Retrieved April, 2017, from https://www.acefitness.org/certifiednewsarticle/715/electrolytes-understanding-replacement-options/