Analysis of Energy Balance for University Student Cohort

This report provides a comprehensive analysis of energy balance, a critical concept encompassing the relationship between energy intake and expenditure. It begins by defining energy balance and its significance, emphasizing the consequences of imbalances such as undernutrition and overnutrition, including obesity. The report then delves into the first law of thermodynamics, explaining its relevance to energy conversion within the body. It explores the Body Mass Index (BMI) as a key metric for assessing weight relative to height, discussing its measurement, importance, and links to various health risks. Furthermore, the report examines total energy expenditure (TEE), its components (BMR, thermogenesis, and physical activity), and how these factors influence body composition and weight management. It differentiates between direct and indirect calorimetry methods for measuring energy expenditure, with a focus on the factorial method. The report also discusses energy intake from food, the role of appetite regulation, and the hormones involved. Overall, the report aims to identify whether a cohort of students are in energy balance.

Running head: ENERGY BALANCE
ENERGY BALANCE
Name of the Student:
Name of the University:
Author’s Note:

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Table of Contents
Introduction................................................................................................................................2
Reference....................................................................................................................................5
Table of Figures
Figure 1: BMI Chart...................................................................................................................3

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Introduction
Energy balance refers to the balance between the energy intake as well as the energy
intake. Moreover, it helps to balance the calories taken by food consumption compared to the
calories burnt by physical activity (Romieu et al. 2017).
Energy balance is important to maintain the BMI range to normal. Due to insufficient
energy balance, the person may suffer from undernutrition or overnutrition. When energy
intake is more than energy expenditure, one can gain a positive energy balance; as a result
weight gain occurs (Caldwell, Eaton and Konner 2019). On the other hand, if the energy
intake is less than energy expenditure, one can have negative energy balance; as a result,
weight loss occurs (Romieu et al. 2017). Both undernutrition and overnutrition are types of
malnutrition. Positive energy balance causes over nutrition that is when one consumes more
nutrients than the daily need every day. On the other hand, negative energy balance causes
undernutrition that is when, one consumes fewer nutrients than the daily need every day.
1st law of thermodynamic is the law of energy conversion. There are two types of
energy conversion, which includes heat and thermodynamic work. According to the first law
of thermodynamics, of the isolated system, the total energy is always constant (Wang 2020).
Energy transforms from one state to another, but it cannot be destroyed or created; all energy
transformed to heat at the end. The formula of the first law is ∆U= Q-W; where Q is supplied
energy quantity and W is the amount of thermodynamic activity and U refers to change in
internal energy of the closed system.
BMI or Body Mass Index refers to the value that is derived from the weight (mass)
and the height of an individual. It is a key index to relate weight with height. The ‘BMI=
weight in kg/ height in m2’. BMI can indicate whether an individual is underweight; normal
weight; overweight and obese. WHO has provided a standard BMI chart to record the obesity
statistics from early 1980 (WHO 2020).

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Figure 1: BMI Chart
(Source: WHO 2020)
It is necessary to measure the accurate BMI as it has a link with the risk of various
diseases and early death. As mentioned by WHO (2020), BMI helps to assess the health risk
of general population. With the increased BMI, the risk of diseases likes diabetes;
cardiovascular disease; hypertension; stroke; osteoarthritis and some cancer increases. It is
considered as the benchmark to decide whether the person is overweight to control the
medical conditions relating to obesity.
Total Energy Expenditure (TEE) refers to the energy amount, which an individual
requires to carry out the physical functions; for example, circulating blood; breathing;
exercising and digesting food (Caldwell, Eaton and Konner 2019). It helps to prevent weight
gaining as the energy intake can be balanced with the energy expenditure. The basic
components of TEE are BMR; physical activity and thermogenesis. If the physical activity
level of a person is high, then the BMR level will also increase with the thermogenesis; as a
result, the weight gain cannot occur and the risk of overweight will be reduced.
Physical activity level depends on age; gender and body composition. With the
increased physical activity, the body composition of an individual will be changed as it
promotes fat loss and maintains the lean-tissue mass. Moreover, moderate physical activity
helps to regulate the blood circulation, for which physical and psychological consequences
can be counteracted (Wang 2020).
Direct calorimetry helps assessing energy expenditure by measuring the heat
production of body. On the other hand, in indirect calorimetry, the energy expenditure can be
determined by calculating the oxygen consumption amount and production of carbon dioxide

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(Romieu et al. 2017). In the case of food and nutrition, the direct calorimetry is used vastly to
measure the heat production and in biochemistry, the indirect calorimetry is used vastly to
measure the intake of O2 and output of CO2.
Energy is necessary to live and to do the works, which one gets from food. Energy
intake refers to the total energy of consumed foods that an individual gets from the major
source of the dietary energy, including carbohydrate; protein; fat as well as alcohol (Ingram
et al. 2016). The requirement is different among individuals. Food energy helps to meet the
needs of body, includes protein synthesis; maintaining body temperature; muscle function;
respiratory and cardiac function.
The Hypothalamus controls appetite regulation. There are various types of hormones,
which regulate the appetite. It includes:
Leptin: adipose tissue secretes the hormone to increase the food intake capacity to
reduce hunger (Ingram et al. 2016).
Ghrelin: The Stomach and small intestine produce the hormone when the stomach is
empty and increases hunger.

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Reference
Caldwell, A.E., Eaton, S.B. and Konner, M., 2019. Nutrition, Energy Expenditure, Physical
Activity, and Body Composition. Oxford Handbook of Evolutionary Medicine, p.209.
Ingram, J.R., Walker, E.G., Pahl, M.C., Lo, K.R., Shin, H.S., Lang, C., Wohlers, M.W.,
Poppitt, S. and Sutton, K.H., 2016. Activation of gastrointestinal bitter taste receptors
suppresses food intake and stimulates secretion of gastrointestinal peptide hormones in
healthy men. European Obesity Summit (EOS).
Romieu, I., Dossus, L., Barquera, S., Blottière, H.M., Franks, P.W., Gunter, M., Hwalla, N.,
Hursting, S.D., Leitzmann, M., Margetts, B. and Nishida, C., 2017. Energy balance and
obesity: what are the main drivers?. Cancer Causes & Control, 28(3), pp.247-258.
Wang, L.S., 2020. The First Law: The Production of Heat and the Principle of Conservation
of Energy. In A Treatise of Heat and Energy (pp. 37-59). Springer, Cham.
WHO 2020. Body Mass Index - BMI. [online] Euro.who.int. Available at:
<http://www.euro.who.int/en/health-topics/disease-prevention/nutrition/a-healthy-lifestyle/
body-mass-index-bmi> [Accessed 2 April 2020].