I Am What I Eat

“I Am What I Eat”
I am What I Eat
Why do we need Food?
 Energy
• Muscle movement
• Body temp
• Measured in kJ (kilojoules)
Eg an apple has 224 kJ of energy
(224,000 Joules)
 Growth
• Material for cell growth
• Replacing old cells
 Keeping healthy
• To keep cells & organs
functioning properly
Food Groups
All food contains water
– lettuce 93%, peanuts 5%
• Protein
– Can’t be stored, eat regularly
– Material for cell growth /
– Used in muscle tissue
• Fats / Oils (Lipids)
– 2.5 times energy of carbs.
– Eg marg, butter, fried food
• Vitamins & Minerals
– Important in cell reactions
– In: fruit, beans, nuts, meats
• Carbohydrates
– Sugars:
• Provide fast energy
• Eg fruit, honey, lollies
– Starch: provide
• Provide slow release energy
• Eg rice, potatoes
– Cellulose
• Aka “fibre”
• Eg fruit, veges, cereals
Note: Excess energy is stored
as fat on the body.
Vitamin C
(what’s the big deal?)
• An antioxidant
• Important in collagen synthesis
– Scurvy...onset 1-6months after switching to
Vit C free diet
• Important in numerous other processes
• Generally: enough vits and minerals in
most western diets (excess excreted –
berocca!, excess toxic?)
Nutritional Panels
Nutritional Panels
• List ingredients (largest to smallest)
• List allergens (food that cause allergic reactions,
eg nuts)
• List food additives (chemicals/substances added
to food to enhance flavour, taste appearance)
• Give serving size so:
– You can compare to other foods
– You know how big a reasonable portion is
– You know how much nutrients a portion gives
• Show %RDI or how much of each food type the
food contributes to your recommended daily
Food additive list: http://en.wikipedia.org/wiki/E_number
Double Down Nutritional Panel
1. How big is one serve / portion?
2. How much energy from one serve?
3. How many double downs could you eat before you reach your
daily energy of 9000kJ?
4. What percentage of fat? (look at total fat per 100g)
5. How many grams of sodium (salt)?
6. Which food types (fat, carbohydrates, proteins) are high?
7. Are double downs healthy to eat? Why, why not?
Fast Food Diet
Task: Build up a poster of a one day diet of fast food that is “healthy” or
• Total energy MUST NOT EXCEED 9270kJ (average daily energy need
for a 14 year old male)
• MUST contain lipids (fats or oils), vitamins and minerals, protein,
carbohydrates (sugar, starch, fibre).
• Include a source of CALCIUM & IRON
• * less than 70g of fat
• ** les than 6g of salt
Food tests
Benedict’s Test  Simple Sugars
• Add a few drops of
Benedict’s solution
(blue) to solution to
be tested (5mL)
• Heat carefully
• Yellow / green / brick
red colour change
indicates simple
Iodine Test  Starch
• Add a few drops of
iodine (yellow) to
solution to be tested
• Blue-black colour
change indicates starch
Biuret Test  Protein
• Put solution to be
tested in a test tube
• Add an equal volume
of sodium hydroxide
• Add 1-2 drops of
copper sulfate
solution (CuSO4)
• Purple colour
indicates protein
Filter Paper Test  Fat
• Rub sample onto filter
paper. Label, do the
same with water.
• Allow to dry
• Translucent (semisee through) marks
indicate fat
Ethanol Test  Lipids
• Put 1mL of ethanol into a Emulsion = Suspension of
two liquid ingredients that
test tube. Add a few
do not dissolve into each
drops of oil or small
other (eg oil & water)
piece of crushed up
food. Shake, add 1mL of
• Cloudy colour indicates
fat or oil
What does Bile do?
Do This:
Mix a little oil + vinegar in a test tube. Observe.
Add a small pinch of mustard, mix. Observe.
Results Copy title then copy & complete below:
1. Oil and vinegar d_______ mix
2. The mustard emulsified the oil (this means it spread
the o____ through the v_____)
3. Bile e_____ oil and fat in the s____ i_________. This
helps d_________ by breaking lipids like f__ and
o____ into smaller pieces.
What is a Balanced Diet?
• Contains all the food groups:
– carbohydrates, lipids (fats & oils), protein,
vitamins & minerals
– in the right amounts
• Has the right amount of energy:
– 9,270 kJ or 9.3 MJ (for 14yr old male)
Consequences of an Unbalanced
Vitamins &