One of the limitations is the lack of the equipment used to determine the amount of macronutrients in food. Some food has many ingredients mixed in and it is difficult to determine without a given apparatus or technique to determine the correct amount of macronutrients in that particular food. This affects the method as when estimation is made on the content of protein, carbohydrate and fats in the food; the result when calculating the weekly percentage is affected as the level of accuracy on the value is decreased.
Results
Food Dairy
Nutrition Contents
Week 1
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Amount of Calories from Nutrition
Day 1
Total Calories = 1113.4 calories/day
Nutrition Percentage Based on the Total Daily Calorie
Day 2
Total Calories = 1543.66 calories/day
Nutrition Percentage Based on the Total Daily Calorie
Day 3
Total Calories = 1488.5 calories/day
Nutrition Percentage Based on the Total Daily Calorie
Day 4
Total Calories = 1161.1 calories/day
Nutrition Percentage Based on the Total Daily Calorie
Day 5
Total Calories = 1160.2 calories/day
Nutrition Percentage Based on the Total Daily Calorie
Day 6
Total Calories = 1488.5 calories/day
Nutrition Percentage Based on the Total Daily Calorie
Day 7
Total Calories = 1168.4 calories/day
Nutrition Percentage Based on the Total Daily Calorie
Calories from the Nutrition Component from Days 1-7
From the result it is shown that the total calorie intake for the week is 8767 calories, where 41% of it comes from protein, 35% comes from carbohydrates, 24% comes from fats and since there were no intake of alcohol, it did not make any contribution towards the total calories. It can be seen that the amount of protein taken is nearly half of the total calories, where the fats and carbohydrates contribute approximately half each of the rest of the total weekly calories intake.
Week 2
Day 8
Day 9
Day 10
Day 11
Day 12
Day 13
Day 14
Amount of Calories from Nutrition
Day 8
Total Calories = 1489.4 calories/day
Day 9
Total Calories = 986.8 calories/day
Day 10
Total Calories = 1300 .3 calories/day
Day 11
Total Calories = 970.7 calories/day
Day 12
Total Calories = 1535.8 calories/day
Day 13
Total Calories = 1488.5 calories/day
Day 14
Total Calories = 986.8 calories/day
Calories from the Nutrition Component from Days 8-14
It can be seen that 8758 calories is the total calorie intake for the week. Protein takes up nearly half of the total calorie intake at 47%, where carbohydrates and fats contribute towards the other half at 25% and 28% respectively. As there were no consumption of alcohol, it did not add any calories to the total calories intake, hence contributed to 0% of the total weekly calorie.
Calculating Basal Metabolic Rate (BMR)
Week 1
Personal Characteristics
Sex = Male
Weight = 81kg
Height = 175cm
Age = 18
BMR (Men) = 66 + (13.7 x 79) + (5 x 175) - (6.8 x 18)
= 1928 calories/day
= 13496 calories/week
Week 2
Personal Characteristics
Sex = Male
Weight = 79kg
Height = 175cm
Age = 18
BMR (Men) = 66 + (13.7 x 79) + (5 x 175) - (6.8 x 18)
= 1901 calories/day
=13307 calories/week
The basal metabolic rate for week 1 is 13496 calories per week, whereas it is 13307 calories per week for week 2. There is slight change in the BMR value with a 189 calories difference.
Calculating Active Metabolic Rate (AMR)
Week 1
Activity Level: Moderate (Moderate exercise/sports 3-5 days/week), conversion factor – 1.55
AMR = BMR x Conversion Factor
AMR = 1928 x 1.55
= 2988 calories/day
= 20916 calories/week
Week 2
Activity Level: Heavy (Hard exercise/sports 6-7 days/week), conversion factor – 1.725
AMR = BMR x Conversion Factor
AMR = 1901 x 1.725
= 3279 calories/day
= 22953 calories/week
The active metabolic rate in week 1 is 20916 calories per week and 22953 calories per week in week 2. There is an incline in the value of calorie by 2037 calories.
Discussion
In everyday life, human uses energy in order to perform daily activity. The energy required comes from macronutrients in forms of calories and this is necessarily for the body to operate appropriately. The BMR is responsible for burning up to 60%-70% (NHMRC 2005) of the total calories expended for basic use such as breathing.
When macronutrients are taken into the body, they undergo several digestion process, however each macronutrients undergo different series of digestion.
The metabolism either breaks the macronutrients into smaller substance or building it up. The cells then use a small portion of their energy to absorb a much higher energy from the macronutrients during this process.
There are two processes of metabolism, the anabolism and catabolism. The bonds within each individual macronutrients are usually broken down, so gets torn down into a much smaller macronutrients through method such as hydrolysis (Marieb & Hoehn 2010). This process is known as the catabolism (Marieb & Hoehn 2010) where substances are broken down into smaller substances. Energy in forms of ATP is released this way when glucose is broken down.
When macronutrients are broken down into, they are presented as chyme. Chyme gets released from the stomach into the small intestine during the intestinal phase. During this phase, hormones are released from the pancreas to aid the digestive process. The amino acid from denatured protein is split into individual acid by the pancreatic and brush boarder enzyme, carboxypeptidase (Marieb & Hoehn 2010). Another brush boarder enzymes, aminopeptidase digests the enzyme.
Lipids (Fats) are digested in the small intestine. Lipase digests the fat by catalyzing it. It breaks down the fats by removing two fatty acid (Marieb & Hoehn 2010), consequently yielding fatty acids and monoglycerides.
Carbohydrates are mainly broken down into the small intestine. Within the small intestine, pancreatic amylase breaks down the polysaccharide carbohydrates down into disaccharide (McCarter 2003). It then produced lactase, sucrose and maltose, which break down those disaccharides into monosaccharide. This can now be absorbed in the small intestine.
To maintain good health, the recommended dietary requirement for protein, carbohydrates and fats has to be adequate. According to Marieb and Hoehn (2010), the recommended amount of protein intake is 0.8g per kilograms of body weight, however the amount of carbohydrates varies between 45-65% of a person’s total calories. The recommended intake for fats is researched to be 30% or less of the total daily calorie intake according to the American Heart Association (Marieb & Hoehn 2010), however saturated fat should be 10% or less. If a balanced diet is not maintained, such as eating excess protein, it could cause the body to undergo seizures and bone loss (Marieb & Hoehn 2010). It also increases the risk of heart disease (NHMRC 2005).
Moreover over consuming carbohydrates increases the chance of obesity (NHMRC 2005) and diabetes as there is large excess of sugar within the body, but under consuming causes the body to digest internal organs such as muscle for energy. Lastly eating excess amount of fat increases the chance of weight gain as fat contains double the calorie of carbohydrates and protein. It also increases the chance of having high cholesterol within the blood, which also increases the risk for heart disease (NHMRC 2005).
In week 1, from figure 1.1, it shows that the amount of protein intake for the whole 7 days was 47% of the total weekly calorie intake of 8767 calories. Consequently approximately 3594 calories and 899 grams are allocated to protein during the first 7 days. This is approximately two times higher than the recommended daily intake of 65grams per day and 454 grams per 7 days. This is also the same for the following 7 days, where 47% of the total weekly calorie intake of 8758.3 is from protein, in figure 1.2. However since the some body weight of 2kg was lost during the second week, the required daily protein intake is 63 grams per day and 442 grams per 7 days.
This evidently showed that for the first week and second week, the daily intake of protein is higher than the recommended intake and as there were dramatic amount of protein intake in excess, this could increase weight gain as the excess protein are stored as fat but this depends on the intake of carbohydrates and fat as well.
Furthermore, it leads to bone loss. The metabolising of the sulfur-containing amino acids increases the blood acidity (Marieb & Hoehn 2010), consequently calcium is pulled forms the bones to buffer the acids. This causes a lack in calcium within the bone, hence disrupting the bone’s homeostasis and causes bone to become fragile.
Nevertheless, eating excess protein is usually acceptable for athletes and bodybuilders. This is due to the fact that their muscle cells get worn from the physical exercises. By consuming high protein in this case it is not severely concerned as it is known from the conversion factor during the calculation of AMR that moderate exercise was performed 5 days a week for week 1 and 7 days a week for week 2. The exercises cause the muscle cell to become worn out and break down, due to cardio and weight lifting. New muscle cell are then rebuilt, in which protein is used to support its growth (Layman 2009). This is due to the process known as hypertrophy (Marieb & Hoehn 2010), where the muscle tends to increase in size as the muscle fibers increases in side to be able to lift the intended load (weight).
It is also said from studies conducted by Layman (2009) that adults benefit from protein intake that is above their daily minimum. This is due to that protein maintains the body composition and motility as well as improving blood lipids and help control food intake.
The carbohydrate intake for week 1 and 2, at 25%, from figure 1.1 and figure 1.2, is approximately less than twice the amount of the recommended minimum carbohydrate intake at 45% of the total calorie. By lacking carbohydrate, this could cause the body to undergo into a condition called ketosis. This happens when the body uses the stored fat energy fast and in extreme cases absorbs nutrient from internal organs such as the muscle. Though, from research conducted by McCarter (2003), those who consume less than the recommended carbohydrate intake tends to lose more fat mass at 7.6kg in 3 months than those eating within the calorie deficit zone at 4.2kg in 3 months. This shows that by consuming low carbohydrates, it does not potentially cause a health risk to those with medium to high body fat percentage, but those with low body fat percentage has a greater chance of undergoing ketosis (McCarter 2003).
Also from figure 1.1 and 1.2, the weekly fats intake is said to be both 28% of the total weekly calorie intake, which is within the required recommended fats intake. This shows that the intake for fats meet the body’s energy needs. Since fat has the highest energy density (NHMRC 2005) out of the other micronutrients, the adequate intake met the need for essential fatty acids and the amount of fat in the diet that is needed to absorb fat-soluble vitamins. From recent studies, conducted by Jequier (2004), by consuming fat content within the recommended amount, it increases disease prevention.
Furthermore it was found from the BMR results that the recommended basal metabolic rate is 13496 calories for the first 7 days and 13307 calories for the following 7 days. However, from calculation, the amount of calorie consumed in the first 7 days was 8767 calories and 8758 for the following 7 days. This is considered unhealthy because the body will not have enough calories to use as energy to function normally. This could cause the rate of the metabolism to slow (Cook 2002), could cause the body to absorb macronutrients from the muscle in replacement, consequently undergoing ketosis.
Also, the calories consumed did not meet the recommended requirement for the active metabolic rate. For the first 7 days, the AMR was calculated to be 20916 calories, and 22953 calories for the following week from the AMR results. For this reason the AMR for week 1 and 2 is much higher than the calories consumed. This shows that not only were there not enough calories to cover the basic body function such as digestion and breathing, but also not enough calories to cover the daily activity performed such as exercises and walking.
Generally it is acceptable consume less calories than the daily recommended calorie intake for fat lost, but in extreme cases such as this where the consumed calorie was over 1000 calories less than the active metabolic rate, the body could potentially undergo into a condition called ‘starvation mode’ (Hanson 2003). This is the body’s way to defend against starvation, and when this happens, the stored fat, which contains a rich amount of calories in the body, is protected, hence the body uses lean tissue or muscle (Hanson 2003) to provide it with some of the calories needed to keep the body functioning. This process increases muscle loss as well as lowering metabolic rate.
Nevertheless, from the AMR results it can also be seen that the active metabolic rate for the first week is lower than the active metabolic rate for the second week, but the amount of calories consumed for the first week is approximately 9 calories more than the second week. The incline in AMR in week 2 from week 1 is due to the rising in physical activity. This result supported the hypothesis, ‘as the level of physical activity increases, the active metabolic rate also increases’.
In week 1, the activity level was moderately performed with a conversion factor of 1.55, however during the second week, the activity level was heavily performed with a conversion factor of 1.725. This causes the AMR to rise to 2037 calories more as the body requires more energy to cover the extra hard work such as exercising 6-7 days as oppose to 3-5 days.
An increase in physical activity causes the body to work more often. Such as that the heart beats faster, more muscle movement, and more breathing involved. The movements of these muscles are operated by aerobic and anaerobic respiration. Both respirations are generated by the breakdown (catabolism) of glucose to create energy in the forms of ATP (Marieb & Hoehn 2010). When the level of physical activity was increased, the body requires more energy to aid the activity; hence AMR also rises, as more calories are required to convert to glucose for the respirations.
Though, if the calorie intake were to increase dramatically well above both BMR and AMR, a medical condition called obesity occurs. Obesity occurs when there is a lack of energy balance (Melbourne Bariatrics 2011). This is due to that there are more energy consumed than the energy burnt. This causes a collection of energy which then gets stored as fat. When this occurs often, more energy are stored as fat, which makes the person become severely overweight and obese.
The amount of calorie consumed should be close the recommended AMR, where consuming well below causes anorexia and consuming well above daily causes obesity (Melbourne Bariatrics 2011). It is difficult to consume well above AMR while doing high intensive exercise, as AMR is proportional to the physical activity level, consequently as physical activity level increases, AMR also increases. Obesity occurs to those people that have an inactivate lifestyle but are actively eating. It could also occur through genetics.
To reduce the chance of obesity, it is vital to consume the same or less calorie coming in than going out. This can be done through actively performing exercises (Melbounrne Bariatrics 2011), which uses more calories (glucose) to created energy or eating a healthy balanced diet.
Overall, the investigation gives a clear view of a person’s nutrition, metabolism and energy balance, in which is shown to be poor as there are more calories out than in, however there are some limitations presented. The limitation was that, since the food diary is based on a 2 weeks diet, it does not determine the person’s overall health, but rather just the health condition between the 2 weeks period. Also another limitation is not being able to monitor the exercise. Since it is based on the conversion factor, it could be that even though in week 1 the exercise was considered moderate as it was performed 3-5 days a week, but the workout could have been more intense than when the exercise was performed 6-7 days a week in week 2. This affects the level of accuracy of the AMR calculations.
However, the aim of the investigation was achieved through performing the experimental method on calculating the nutrition values, and BMR and AMR for the first and second week.
Conclusion
Overall the aim of the investigation was supported through the findings in the result by following the experimental method. Though there were some limitations, such as not being able to accurately monitor the exercises and only being able to observe the amount of nutrition taken over a 2 week period, it was found that the hypothesis, ‘As the level of physical activity increases, the active metabolic rate also increases’ was supported by the results. Where it shows that the value for AMR in week 1 is much lower than the value for AMR in week 2 due to the increased in physical activity level. Lastly, from previous research on the recommended macronutrients intake, it was also found that the nutrition consumed over the two weeks period such as protein was higher than the recommended daily intake, whereas the carbohydrates consumed did not meet the intake, but the amount of fats consumed was within the recommended range.
Reference
Cook, N 2002, Starvation; Medical Department Have Provided New Data on Starvation, The MIT Press, Massachusetts, USA
Hanson, S 2003, ‘Your BMR and what you can do about it’, Vibrant Life, vol. 19, no. 2, pp. 16, viewed 21 August 2013, via Academic OneFile
Jequier, E 2004 ‘Response to and range of acceptable fat intake in adults’, European Journal of Clinical Nutrition, vol. 53, no. 4, pp. 84-94, viewed 21 August 2013, via Academic Search Premier
Layman, D 2009, ‘Dietary Guidelines should reflect new understandings about adult protein needs’, Nutrition & Metabolism, vol. 6, no. 12, pp. 6-12, viewed 21 August 2013, <http://www.nutritionandmetabolism.com/content/6/1/12>
Marieb, E & Hoehn, K 2010, Human Anatomy & Physiology, Pearson Education, San Francisco, CA.
McCarter, D 2003, ‘Low carbohydrate diet effective for adults’, Journal of Family Practice, vol. 52, no. 7, pp. 515, viewed 21 August 2013, via OneFile
Melbourne Bariatrics 2011, ‘Problems With Obesity’,’ Causes of Obesity, vol. 1, no.3, pp. 1-1, viewed 21 August 2013,
<http://www.melbournebariatrics.com.au/causes-of-obesity.html>
NHMRC 2005, ‘Nutrient Reference Values For Australia and New Zealand’, Recommended Dietary Intakes, vol. 1, no. 1, pp. 1-317, viewed 21 August 2013,
<http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n35.pdf>