Sample Essay On No-Fat Diet

The fats in our diet are often accused of causing many health problems. Fats, however, are a vital nutrient for ideal fitness. To know more about how fats help in our diet, let us first understand how our bodies consume the food that we eat and how we store them as energy for later use. Whenever we eat food, the stomach mixes sugars, fats or proteins with fluids containing enzymes and acids. These are then digested these larger molecules are broken down and absorbed into the intestine and transferred to the blood. If they are fat then they could be triacyglycerides, cholesterol and free fatty acids and the triglycerides will break down and be discharged to the bloodstream and can be immediately utilized or stored for later use. Carbohydrate-rich foods are broken down into glucose, and fats are stored as triglycerides (McCullogh, 2014; NHS, 2015).
Carbohydrates are usually the first to be broken down but when there is a low blood sugar level decreasing insulin it triggers a hormone sensitive lipase for fats to be broken down. Fats are stored in adipose tissue as triglycerides but they can also be ingested by eating. In the latter they have to go through the gastrointestinal tract to the duodenum and ileum in the gut. However, the triglycerides cannot pass through the gut wall and an enzyme called lipase needs to cleave (lipolysis) the triglycerides into smaller units of glycerol and free fatty acid (Leninger, 1993). This enables the fats to pass through the gut and into the body via a transporter. Once inside they reform into triglycerols.
These triacyglycerides are stored in lipid droplets are also broken down by a lipoprotein lipase which goes into the surrounding tissues. The lipid droplets (and could be packaged in lipoproteins like HDL or LDL) are found in all cell types including adipose tissue. Once broken down into glycerol and free fatty acid the latter is transferred into the mitochondrial matrix after binding Coenzyme A. The process called beta oxidation is the process of breaking down the carbon chain and starts first at the tail end then four enzymes act viz. acyl coA dehydrogenase, enoyl Co-A hydratase, 3-hydroxy CoA dehydrogenase, thiolase (Leninger, 1993) to reduce it. These enzymes add and subtract hydrogen and donate them to two coenzymes: flavin or nicotinamide (FADH and NADH). The final unit is acetyl-CoA (acetyl is the basic unit that used in respiration) which goes through the Citric Acid cycle.
The Citric Acid Cycle is a series of chemical reactions that happen inside the mitochondria. In this cycle they use acetyl-CoA as a starting block which can be derived from fats, sugars or protein. The name comes from the fact that a citric acid is used at the start of the process then regenerated at the end. The reactants are Acetyl-CoA, 3 NAD+, Coenzyme Q, ATP, Pi, 2 waters. The final products are CoenzymeA, 3 NADH + 3 Hydrogens + Hydrogenated Coenzyme Q + 2 carbon dioxide + ATP. However, with the Citric Acid Cycle you don’t get a huge influx of ATP. Most ATP generated are made with the electron transport chain which goes from the internal mitochondrial membrane. It uses the 3 NADH, and hydrogens to transfer electrons from electron donors to electron acceptors via redox reactions. An electrochemical gradient is formed which drives ATP synthesis ADP + Pi = ATP. This is one reason as aerobic respirators we need oxygen as it the final acceptor in this chain (Leninger 1993).
The fatty acid will be two carbons shorter and then it can repeat. Many free fatty acids are 16 carbons long which would make 7 cycles of beta oxidation after after the citric acid cycle and the electron transport chain it translates to 131 ATP. The ATP is the energy unit which helps to drives things like our muscles. Fatty acids thus are highly energetic. Firstly they can be stored nicely in a highly compact area of fatty droplets because they contain no water (whereas carbohydrates are more hydrated). Secondly, when they are reduced they release 9 kcal/gram (this is far more than carbohydrates). So fats have a very high yield of energy per gram compared to any other source of nutrients.
When we do not use much energy, especially the ones from fats, it would be deposited in the adipose tissue and lipid droplets in the cells. The adipose tissue, also known as stored fat, covers the nerves, offers insulation and cushion to internal organs, and transports vitamins such as A, D, E, and K in the body. It is also the main storage of energy, which is accessible to activities that require more energy. Too much consumption of calories without burning enough of them would likely result increased weight. This is when health is at higher risk. However, we must not stop consuming fats altogether due to the reasons discussed above. It should be kept in mind that not all fats are risky (McCullogh, 2014; NHS, 2015).
There are three types of fats. The first is the saturated fat (see Figure 1). It is commonly found in animal products such as meat, milk, and eggs. It is the culprit for increasing the bad cholesterol in the body, which accumulates and blocks the bloodstream. This is because cells latch onto them to live with the fat. The cholesterol is taken from the liver and distributed to the body as opposed to being taken from body tissue and being brought back to the liver. The second type of fat is trans fat. It takes shape when oils harden. It is usually found in processed foods, fried foods, baked goods, and spreads.This is also associated to bad cholesterol. Both the saturated fat and the trans fat must be taken in moderation, monitored, and even limited in one’s diet (Rustan & Drevon, 2005; NHS, 2015; Harvard T.H. Chan, 2015).
Figure 1 Saturated fat (made with ChemDoodle online web.chemdoodle.com)
The last type of fat is the unsaturated fat (see Figure 2). It is usually found in high quality oils such as olive oil, vegetable oil, and canola oil. It can also be found in nuts and fish. Furthermore, it is pertained to as the good fat or good cholesterol. This cholesterol is taken from the body tissue in the same way that a garbage truck takes trash and brought to the liver for proper disposal (Rustan & Drevon, 2005; NHS, 2015; Harvard T.H. Chan, 2015).
Figure 2 Unsaturated Fat (made with ChemDoodle online software webchemdoodle.com)
Each of these fats consists of fatty acids. They are significant in metabolism, enabling the transport and storage of energy. They are also the vital element of all membranes. The basic structure of fatty acid consists of carbon chains, along with the methyl group on one end and the carboxyl group on the other end. The saturated type of fatty acids is saturated with hydrogen. These fatty acids are commonly straight hydrocarbon chains, having an even amount of carbon atoms of about 12 to 22. Trans fatty acids form through hydrogenation. It mimics saturated fats (Rustan & Drevon, 2005).
Unsaturated fatty acids, on the other hand, consist of a carbon and carbon double bond occurring in a variety of positions. This is the case with the monounsaturated type. It has a chain length consisting of 16 to 22 carbon atoms and a double bond that has cis configuration. The double bond has hydrogen atoms on each side, facing a similar direction. Due to the double bond, the acyl chain is restricted. As for the polyunsaturated type, the initial double bond can be found along the third and fourth carbon atom. The initial bond could also be found along the sixth and seventh carbon atom. Its double bonds are detached from one another through methylene grouping (Rustan & Drevon, 2005).
Lipids or fats may be envisioned in the illustration below. It is the fluid-mosaic model of the membrane structure of 1972. The illustration is composed of a figure similar to a sandwich where there are two surfaces holding everything together. These two surfaces are the fats in the fluid bilayer phase, which hold in integral proteins (Nicolson, 2014).
No fat in a diet would cause people to rely on fat reserves internally. If there are little fat reserves and if you are quickly respiring carbohydrates you may need to burn the next best thing proteins. Other than creating energy there are several fats that serve several purposes in the body e.g. arachnidonic acid is needed for signaling, docohexanoic acid is important in the brain (so eat more fish) and omega fatty acids are important. So the best answer is to consume monounsaturated and polyunsaturated fats rather than trans and saturated fat but in moderation.

References

Harvard T.H. Chan. (2015). Fats and cholesterol: Out with the bad, in with the good. Retrieved from http://www.hsph.harvard.edu/nutritionsource/fats-full-story/
McCullogh, D. (2014). How our bodies turn food into energy. Group Health Cooperative.Retrieved from http://www.ghc.org/healthAndWellness/?item=/common/healthAndWellness/conditions/diabetes/foodProcess.html
NHS. (2015). Fat: The facts. Retrieved from http://www.nhs.uk/Livewell/Goodfood/Pages/Fat.aspx
Nicolson, G. L. (2014). The fluid-mosaic model of membrane structure: Still relevant to understanding the structure, function, and dynamics of biological membranes after more than 40 years. BiochemicaetBiophysicaActa, pp. 1451-1466.
Rustan, A. C., &Drevon, C. A. (2005). Fatty acids: Structures and properties. Encyclopedia of Life Sciences.New Jersey: John Wiley & Sons, Ltd.
Chemdoodle. Retrieved from web.chemdoodle.com
Leninger, A. L., Dalud L. Nelson, and Michel M. Cox. "Principles of biochemistry." New York: Worth Publishers (1993).