Session 1 Lectures 1.1/1.2 Flashcards
(28 cards)
Define and give approximate values to the components of your daily energy expenditure
The daily energy expenditure of a 70kg male is around 12000kJ and that of a 58kg adult female is around 9500kJ
This expenditure consists of three components:
- Basal metabolic rate
- Energy fir voluntary physical activities
- Diet induced thermogenesis
Define and explain the Basal metabolic rate
The BMR is a measure of the basal energy ( the basic energy needed to sustain all the basic functions of an organism) required to maintain life and the functioning of the various tissues of the body at physical, digestive ad emotional rest.
The major tissues contributing to the BMR :
- Skeletal muscle 30%
- Central nervous system - 20%
- Liver - 20%
- Heart - 10%
How can you calculate the BMR
A rough estimate of the BMR in Kj/24hr of non obese individuals can be calculated using
BMR = 100 x weight in Kg
Define and explain energy expenditure through voluntary physical activity
The energy required by skeletal and cardiac muscle for voluntary physical activity contributes to our daily energy expenditure
How can you calculate the total daily energy required for physical activity
An estimate can be made using the following rules:
- BMR + 30% of the BMR for a sedentary person
- BMR + 60-70% of the BMR for a person who engages in 2hrs of moderate exercise a day
- BMR + 100% of the BMR for a person who does several hours of heavy exercise a day.
Define and explain Diet induced thermogenesis
Our daily energy expenditure includes a component related to processing the food we eat. Following ingestion our metabolic rate increases because rage energy is requires to digest, absorb, distribute and store nutrients.
The energy needed to process the food is equal to approximately 10% of the ingested food.
How do you calculate the daily energy expenditure
The Sum of the BMR plus the dry required for the amount of time spent in each of the various physical activities plus 10% of these values to reflect diet induced thermogenesis
Why is Fat an essential component of the diet
- Fat has an energy content of 37Kj/g and is one of the major energy containing components of the diet. In a typical western diet 45% of the energy requirement id derived from fat.
- Fats have an energy yield 2.2 times greater than carbohydrates or proteins.
- Fat is necessary of the absorbtion of the fat soluble vitamins - A,D,E,K from the gut.
- Certain polyunsaturated fatty acids are not synthesised in the body and must be consumed in the diet.
Why are carbohydrates an essential component of the diet
Carbohydrates are one of the major energy containing components of the diet. In a typical western diet 40% of the energy requirement oil derived from carbs.
Why is glucose essential ?
Tissues such as the brain and red blood cells need a constant supply of glucose as a source of energy. However there is no requirement for glucose in the diet as the body can make glucose by the process of gluconeogenesis and also from the glycerol released from the hydrolysis of triacylglycerol
Why is protein an essential component of the diet
The digestion of proteins results in amino acids which are used in the synthesis of a number of essential N- containing components
- the metabolism of proteins can also be used to derive energy
Why is water an essential component of the diet ?
In an adult 50-60% of the body weight is water. Water is lost from the body through processes such as urination, expired air, through the skin, faeces etc. part of this water is produced during cellular metabolism and the remainder must be made up by drinking to maintain the body’s fluid balance .
Why is dietry fibre necessary in the diet
Non digestible plant material such as cellulose is necessary for normal Bowel function.
Why are minerals and vitamins necessary in the diet ?
Absence of vitamins can lead to deficiency diseases
Explain the clinical consequences of protein and energy deficiency in humans.
Marasmus - protein energy malnutrition most commonly seen in under the age of 5.
Kwashiokor - occurs in a young child when they are displaced from breastfeeding and fed a diet with some carbohydrate, but low protein content.
How do you calculate BMI ?
Weight (Kg) / Height^2 (m^2)
Interpret BMI values
- Underweight <18.5 (men and women)
• Desirable range = 18.5 - 24.9 (men and women)
• Overweight = 25 - 29.9 (men and women)
• Obese = 30 - 34.9 (men and women)
• Severely Obese >35 (men and women)
What is the waist to hip ratio
Health professionals are increasingly using waist to hip ratio in preference to BMI as a better measure of obesity and the risk of cardiovascular disease. The waist circumference is measured and divided by the hip circumference to give a ratio. The WHO states that abdominal obesity is defined as a waist to hip ratio >0.90 for males and >0.85 for females.
Define obesity and the possible risk factors
Obesity is the condition in which excess fat has accumulated in the body in both the subcutaneous and visceral tissues.
Obesity is a risk factor for
- heart disease
- stroke
- types two diabetes
- increased risk of hypotension
describe the factors involved in the regulation of body weight.
Diets, dietary regimes. Long term changes in food cho9ices, eating behaviour and lifestyle.
describe the factors involved in the regulation of body weight.
Diets, dietary regimes. Long term changes in food cho9ices, eating behaviour and lifestyle.
Define cell metabolism.
Cell metabolism is defined as the highly integrated network of the chemical reactions that occur within cells.
Define cell metabolism.
Cell metabolism is defined as the highly integrated network of the chemical reactions that occur within cells.
It is the set processes which derive energy and raw materials from food stuffs and use them to support repair, growth and activity of the tissues of the body to sustain life.
Explain the functions of cell metabolism
Cells metabolise nutrients to provide:
- Energy for cell function and the synthesis of cell components
- building block molecules that are used in the synthesis of cell components needed for the growth, maintenance, repair and division of the cell.
- organic precursor molecules that are used to allow the inter conversion of building block molecules
- biosynthetic reducing power used in the synthesis of cell components (NADPH)
