Essay: Digestive System, Chewing, and Mechanical Digestion

Pages: 4 (1447 words)  ·  Bibliography Sources: 4  ·  Level: College Senior  ·  Topic: Nutrition  ·  Buy This Paper


[. . .] Such reactions can produce muscle loss and put extra strain on the kidneys as the body works to dispose of unused protein by-products" (Hawk 2003). In general, adults should aim to eat a diet composed 40-60% of carbohydrates (Hawk 2003). Carbohydrates are classified as 'simple' or 'complex' and in general it is better to consume complex carbohydrates such as whole grains vs. refined 'simple' sugars because of their higher levels of nutrients and the greater satiety they convey because they take longer to 'break down' within the digestive system (Carbohydrates, 2012, NIH).

Q4.Nutrition & Physical Activity

Most people are aware of the benefits of physical activity as a source of calorie burn. Exercise improves heart health by elevating good (high-density lipoprotein) cholesterol and decreasing unhealthy triglycerides or 'bad' cholesterol (Exercise, 2013, Mayo Clinic). It improves lung function, reduces high blood pressure, contributes to regular digestion, and generally improves all aspects of physical functioning. By building muscle, it increases strength and can protect against bone breaks and fractures. It also increases bone density. It improves mood functions by boosting 'feel good' neurotransmitters in the brain and can be an important component of stress reduction, as well as give a feeling of empowerment to the exerciser. It can provide a source of social engagement and accomplishment.

Q5. Lipids

"Fat provides a more concentrated source of energy than carbohydrate or protein (providing 9 calories per gram vs. 4 calories per gram)" (Barke 2005). This is why fat often has a reputation as a 'bad' nutrient, but it is vitally necessary to human health and survival. As well as satisfying caloric needs, fat plays a vital role in the ability of the body to absorb nutrients. "Fat is required to transport vitamins A, D, E and K, produce hormones, store energy, maintain healthy skin, and protect organs" (Facts about fat, 2010, McKinley Health Center). Consuming unsaturated vs. saturated fats actually lowers rather than elevated 'bad' blood cholesterol. Up to 20-25% of the diet can come from fats, ideally from healthy sources such as vegetable oils, avocados, and nuts and seeds rather than primarily from saturated sources in the form of animal proteins which elevate the 'bad' cholesterol levels (Barke 2005).


Proteins are often called the 'building blocks' of the body and are essential for the construction of immune cells, skin cells, blood cells, and muscle cells (Barke 2005). Proteins are made up of essential amino acids in the form of carbon, hydrogen, and oxygen atoms and a nitrogen (amino) group (Why you need protein in your diet, 2012, For Dummies). Maintaining adequate skin, muscle tissue, bone, red blood cells, and creating new cells all requires protein. Even the neurotransmitters of the brain require protein to function. In general, approximately 15-20% of total calories of the diet should be composed of proteins (Barke 2005). 'More' protein is not necessarily better, contrary to what some athletes believe -- it can put a strain on the body's kidneys and result in the inadequate consumption of other vital nutrients required for daily functioning (Barke 2005).


Barke, Sheri. (2005). Eating for exercise & sports. College of the Canyons. Retrieved:

The basic principles of food safety. (2006). NH Department of Health & Human Services. Retrieved:

Carbohydrates. (2012). NIH. Retrieved:

Causes of the spoilage of food. (n.d.). Food Preservation. Retrieved:

Exercise. (2013). Mayo Clinic. Retrieved:

Facts about fat. (2010). McKinley Health Center. Retrieved:

Haas, Elson. (2012). Digestive aids: Hydrochloric acid. (2012). Healthy Net. Retrieved:

Hawk, Kimra. (2003). Ask an expert: Protein vs. carbohydrates. Providence Health

Services. Retrieved:

Lab: Mechanical and chemical digestion (n.d.). Chapter 38. Retrieved:

Organic FAQ. (2013). Retrieved:

Organs: Large and small intestines. (2012). Children's Hospital of Pittsburgh. Retrieved:

Why you need protein in your diet. (2012). For Dummies. Retrieved: [END OF PREVIEW]

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Digestive System, Chewing, and Mechanical Digestion.  (2013, January 22).  Retrieved October 14, 2019, from

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"Digestive System, Chewing, and Mechanical Digestion."  January 22, 2013.  Accessed October 14, 2019.