Food Science
The affect of diet on health
Learning objectives
Understand the factors affecting energy
requirement
Be able to calculate BMI
Too much of a good thing
22% Britons are obese (BMI over 30)
¾ of people are overweight
30,000 deaths a year:
Heart disease
Diabetes
High blood pressure
Costs the NHS £500 million
Due to high calorie intake
Calorie
From carbohydrates and fats
Calories and joules used to measure energy
1 calorie = amount of energy required to raise the
temperature of 1g of water by 1oC
1 calorie = 4.18400 joules
Food packaging talks in kilo (1000)
calories (this contains 322,000 cal)
How much energy?
16000 Measured in Kj
14000 Primary school kid
12000 St Lukes student
10000
8000
Computer programmer
Female
6000 Male Builder
4000 Pregnant women
2000
0
Primary Pregnant
school kid women
What do we need
Calorie requirements per day are:
Men: 2550 kcal
Women: 1994 kcal
Takes into account:
W = weight in Kgs
H = Height in cms ( 1 foot = 12 inches, 1 inch = 2.54 cms)
Age = Years
What do we get
Average 1994 kcal for women, 2550 kcal for
men
Nutrient Calories per gram
Carbohydrate 4 kcal
Protein 4 kcal
Fat 9 kcal
Alcohol 7 kcal
Good fat and bad fat?
Fat is an energy store, insulation and
padding
2 main types
Saturated fat (animal sources)
Unsaturated fat (Plant sources)
Saturated fat in cholesterol
Can block blood vessels
Angina
Hearth attack
When we get too many
Excessive calories stored as body fat
‘Ideal weight’ for an individuals height
BodyMass Index (BMI) is used to determine
whether a person is overweight
Body Mass Index
BMI = body mass (Kg)
(height(m))2
BMI Weight description
Below 18.5 underweight
18.5-24.9 normal
25-29.9 overweight
30-40 Moderately obese
>40 Severely obese
Learning outcomes
What are the factors affecting energy
requirement?
What is a BMI?