Nutrition, Diet, and Body Weight Flashcards
What is catabolism?
The breaking down of molecules to release energy and reducing power
What is anabolism?
The use of energy, reducing power, and raw materials to make molecules for growth and maintenance
Assuming moderate physical activitity, what is the daily energy expenditure of a 70kg adult male?
12,000kJ
Assuming moderate physical activitity, what is the daily energy expenditure of a 58kg adult female?
9,500kJ
What are the components of daily energy expenditure?
- Basal metabolic rate
- Energy required for voluntary physical exercise
- Diet-induced thermogenesis
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Define basal metabolic rate?
Energy used to support our basal metabolism
What is diet-induced thermogenesis?
Energy we require to process the food we eat
What are the essential components of the diet?
- Fats
- Proteins
- Carbohydrates
- Water
- Fibre
- Minerals and vitamins
Are fats essential as an energy source?
No
How does the energy yield from fats differ from carbohdyrates and proteins?
The energy yield of fats is 2.2 times greater
What are fats necessary for the absorption of?
Fat-soluble vitamins
What are the fat-soluble vitamins?
A, D, E, and K
Give two essential fatty acids
- Linoleic acid
- Linolenic acid
What is the importance of essential fatty acids?
They are structural components of cells membranes, and precusors of eicosanoids
What are eicosanoids?
Important regulatory molecules
What are amino acids the product of?
Digestion of proteins
What are amino acids used in?
The synthesis of essential N-containing compounds
Give 3 N-containing compounds
- Creatine
- Nucleotides
- Haem
How much protein is degraded a day?
About 35g
How is protein excreted in urine?
As urea
What is nitrogen balance?
When N2 intake = N2 loss
What is the average daily protein requirement of an adult male to maintain nitrogen balance?
35g
What is meant by an essential amino acid?
One that cannot be synthesised in the body, and so must come from dietary protein
What is the importance of carbohydrates?
They are the major energy-containing component of the diet
How much energy is provided by carbohydrates?
17kJ/g
What % of an adults body weight is water?
50-60%
What % of a childs body weight is water?
70%
What % of an elderly/obese peoples body weight is water?
50%
What is the average water loss per day?
2.5litres
How is water loss from the body?
- Urine
- Expired air
- Skin
- Faeces
How much water is lost in the urine per day?
1,500ml
How much water is lost in expired air per day?
400ml
How much water is lost by the skin per day?
500ml
How much water is lost in faeces per day?
100ml
How is water gained in the body?
- Cellular metabolism
- Drinking
How much water does cellular metabolism produce?
350ml
What is fibre?
Non-digestible plant material
What is fibre important for?
Normal bowel function
Give an example of a fibre
Cellulose
What are the types of vitamins and minerals?
- Water-soluble
- Lipid-soluble
What is associated with the absence of minerals and vitamins?
Deficiency diseases
Why does starvation in adults lead to loss of weight?
Due to loss of subcutaneous fat and muscle wasting
What do adults who are starving complain of?
- Cold
- Muscle weakness
Where are infections are common in starvation?
- Lungs
- GI tract
What is marasmus?
Protein energy malnutrition
Who is marasmus most commonly seen in?
Children under the age of 5
What are the symptoms of marasmus?
- Appears emaciated, with no obvious signs of muscle wasting, but loss of body fat
- Hair thin and dry
- Diarrhoea
- Anaemia
Is there oedema in marasmus?
No
Who does kwashiorkor typically occur in?
A young child displaced from breastfeeding by a new baby
What features of the diet will lead to kwashiorkor?
Some carbohydrate, but very low protein content
What are the symptoms of kwashiorkor?
- Apathy
- Lethargy
- Anorexia
- Distended abdomen
- Generalised oedema
- Anaemia
What causes the distended abdomen in kwashiorkor?
- Hepatomegaly
- Ascites
What is ascites?
Accumulation of fluid in the peritoneal cavity
Why is there generalised oedema in kwashiorkor?
Due to low serum albumin
How is BMI calculated?
BMI = Weight (kg) / Height2 (m)
What BMI is considered to be underweight?
<18.5
What BMI is considered to be in the desirable range?
18.5 - 24.9
What BMI is considered to be overweight?
25 - 29.9
What BMI is considered to be obese?
30 - 34.9
What BMI is considered to be severely obese?
>35
What is meant by obesity?
When excess body fat has accumulated to the extent that it may have an adverse effect on health
What adverse effects on health might obesity have?
- Reduced life expectancy
- Increased health problems
What is body weight determined by?
The difference between the input of substances into the body, and the output of substances and energy from the body