1a) Name and describe sex-specific forms of obesity with regard to body shape. What are the differences, if any, in health risks, associated with each shape?
Answer : There are various forms of obesity that are signified by age, gender and genetic predisposition. The sex-specific forms of obesity include Android obesity and Gynoid obesity. Both are in contrast with each other with respect to human tendency of developing adipose tissue in the body. The Android obesity is signified by fat deposit in "apple-shape" including shoulder, nape of neck, chest in the upper abdomen which is more evident in males than females. On the other hand, gynoid distribution of fat is signified by causing a "pear-shape" fat deposit around the hip, waist and love handles in the lower abdomen. Gynoid obesity is more prevalent in females than males (Insel, Turner & Ross, 2003).
1b) Name and describe three different methods—among the various existing methods—of assessing body fatness (not BMI). What are some of the key strengths and limitations of each method?
Answer: There are many ways of fat assessment that is level of obesity in a body of a specific individual with respect to nutrition assessment, ways other than BMI include;
Skin fold Thickness - This refers to the measurement of fat in the subcutaneous layers of skin. It is measured using calipers by grasping a fold of skin in the caliper teeth. Is an easy and quick way to measure body fat
Just measures the relative percentage of fat
Requires instrument and some training
Waist to Hip Ratio
This is the ratio of waist and hip measurements; it helps to evaluate fat distribution as well as helps in identification of potential risks to health with respect to level of obesity. Very easy, requires minimal calculation
No training required
This is a technical method that involves opposition or impedance of the body against a minimal electrical current that passes through the body. The lean tissue mass in the body acts as a conductor while the fat mass acts as an insulator hence depicting changes in voltage which in turn signify body fat.
Measures from legs only thus may be inaccurate
1c) See the attached body mass index (BMI) growth chart. This graph has been plotted for an individual. What can you describe about this individual (including sex, age, height, weight, BMI, and BMI percentile)? How would you evaluate her or his health risks with regard to BMI percentile? Is there an indication, based on current understanding, for further assessment for this individual?
Answer: The growth chart shows statistical data of a 16 year old boy with weight 160.6 pounds and height 67inches. According to the Harris benedict BMI formula, his BMI calculates to 25.1 kg’s per meter square. The BMI percentile of this individual falls in the 75th percentile. The BMI signifies a trend towards obesity since it is already in the overweight range (Insel, Turner & Ross, 2003).
1d) For the same individual above, what are the known health risks going into adulthood if his or her condition remains unchecked, compared to an individual who doesn't have any of the health risks outlined in 1c? What does the CDC say about this?
Answer: The BMI signifies a tendency of obesity. The individual is already over weight which indicates a further vulnerability to fat related diseases and illnesses including high blood pressure and high blood cholesterol levels. This indication can reiterate the fact and need of further assessment of blood lipid profile and blood pressure to check out the fat and obesity status. CDC suggests close dietary monitoring as the risk of weight gain increases with increased consumption of energy yielding nutrients. Physical activity on regular basis is also advised (Insel, Turner & Ross, 2003).
1e) Select just one of the factors leading to obesity and describe its characteristics, explaining why it may be important in an individual's development of obesity.
Answer: The prime cause of obesity is the lifestyle pattern of the individual. This includes dietary habits as well as the inclusion of physical activity in the routine. Dietary habits based on consumption of energy dense foods, high saturated fat intake and more of junk food that is not nutrient dense leads to fat deposition in the adipose tissue of body (Insel, Turner & Ross, 2003). Similarly, lack of daily physical activity in routine on regular basis also contributes to inability of fat loss, and weigh gain. These factors are extremely important and crucial to an individual's tendency of developing obesity since these are major contributive factors which increase the risk of weight gain drastically.
2. Four specific pathways have been outlined for the metabolism of carbohydrate (glucose). In your own words, list and describe key components / characteristics of each:2a) Glycolysis: The other name for glucose degradation which converts glucose C6H12O6, into pyruvate, CH3COCOO− + H+. This process thus produces free energy which is then used to make high energy compounds like ATP- Adenosine Triphosphate. In simpler words, glycolysis is a non-oxygen dependent metabolic pathway which ensures that energy is provided to the body at all times throughout the day and night (Insel, Turner & Ross, 2003). 2b) Pyruvate to acetyl CoA: Pyruvate is a complex compound that helps the transformation of acetyl Co enzyme A as part of a characteristic phase in the citric acid cycle. It acts as a catalyst to complete the cycle and make energy utilization possible. 2c) Citric acid cycle: This is a successive sequence of reactions chemically taking place in all aerobic i.e. oxygen dependent organisms in order to ensure smooth generation of energy through the oxidation of acetate. This acetate is derived from energy yielding nutrients such as proteins, fats and carbohydrates into chemical energy. 2d) Electron transport chain: An Electron Transport Chain, also known as ETC is a successive sequence of reactions chemically taking place through compounds that transfer electrons from electron donors to electron receivers. This process takes place through redox reactions with the help of a membrane creating an electrochemical gradient of protons. Eventually it reaches molecular oxygen to complete the process
2e) In sports/fitness nutrition, what is meant by carbohydrate loading? When is considered useful, if at all? Give an example.
Answer: Carbohydrate also known as the Carb-Loading is usually used by sport men and endurance building athletes. It helps them in maximizing the energy stored in muscles. This stored form energy called glycogen found in liver as well as muscles is maximized by consumption of low glycemic index foods that slowly release glucose in the blood without causing disturbance in the serum glucose level. An example is an athlete consuming large meals in diet including fruits, vegetables and whole grains a day before his race so that he can 'load' his carbohydrate store for the upcoming exertion in marathon (Insel, Turner & Ross, 2003).
Question 3: Please provide a detailed explanation of how the body derives energy from the fat at cellular level? List the key steps (e.g. Beta-Oxidation), the part of cell in which the reaction occurs. What is meant by term ‘lipo-genesis’?
The body derives its energy from fats in the form of fatty acids, as they are stored as triglycerides. Fatty acids are both reduced and anhydrous, giving energy to the body. The fatty acids are found in the form of molecules that are water free. One gram of fatty acid generates 9kcal of energy as compared to 4kcal energy from a gram of carbohydrates. Lipases carry out the lipolysis and then the fatty acids are freed from the glycerol. The free fatty acids can easily enter into blood stream and provide energy to the body. The next step involves Beta-Oxidation, in which the long carbon chains of the fatty acid are broken down into acetyl CoA, enabling the latter enter the TCA cycle. This process takes place in ‘mitochondria’ of the cell. Lipogenesis means such a process that converts acetyl-CoA to fatty acids. This is a stage where the energy is stored in the form of fats, as in acetyl-CoA, energy is present in the form of sugars only. Triglyceride synthesis is an integral part of lipogenesis.
Insel, P., Turner, R., & Ross, D. (2003). Discovering nutrition. Sudbury, Mass.: Jones and Bartlett Publishers.