For the IB Biology course, Option A: Human Nutrition and Health

1. Energy in Human Diets
Stephen Taylor
Image: 'untitled'
http://www.flickr.com/photos/28025847@N05/7694792428
Found on flickrcc.net

2. Assessment Statements Obj.
A2.1 Compare the energy content per 100g of carbohydrate, fat and protein. 3
A2.2 Compare the main dietary sources of energy in different ethnic groups. 3
Explain the possible health consequences of diets rich in carbohydrates,
A2.3 3
fats and proteins. (Explain consequences of excess of each separately).
A2.4 Outline the function of the appetite control centre in the brain. 2
Calculate the body mass index (BMI) of a person from their weight and
A2.5 2
height.
Distinguish, using the BMI, between being underweight, normal weight,
A2.6 2
overweight and obese.
Outline the reasons for increasing rates of clinical obesity in some
countries, including the availability of cheap high-energy foods, large
A2.7 2
portion sizes, increasing use of vehicles for transport, and a change from
active to sedentary occupations.
A2.8 Outline the consequences of anorexia nervosa. 2
Command terms: http://i-biology.net/ibdpbio/command-terms/ Assessment statements from: Online IB Biology Subject Guide

3. What is food energy and how can it be measured?
Food energy: from carbohydrates, proteins, fats.
Units: food calories (kcal) or kilojoules (1kcal = 4.18kJ)
1 food Calorie = 1000 calories
(1 calorie = the energy required to raise the
temperature of 1g water by 1oC.)
SI unit: kilojoules
1 food Calorie = 4.1kJ (kilojoules)
As humans are autotrophs, we take
energy from food, in form of
carbohydrates, lipids or proteins.
Image: 'Big Mac'
http://www.flickr.com/photos/7236030@N03/2741811882
http://nutritiondata.self.com/facts/fast-foods-generic/8053/2 Found on flickrcc.net

4. Compare carbohydrate, fats and proteins in
terms of energy storage.
Energy /100g Carbohydrates Fats Proteins
kJ 1,760 4,000 1,720
kcal (Calories) 421 956 411
Image: 'Big Mac'
http://www.flickr.com/photos/7236030@N03/2741811882
http://nutritiondata.self.com/facts/fast-foods-generic/8053/2 Found on flickrcc.net

5. Compare carbohydrate, fats and proteins in
terms of energy storage.
Energy /100g Carbohydrates Fats Proteins
kJ 1,760 4,000 1,720
kcal (Calories) 421 956 411
Carbohydrates are broken down into monosaccharides (sugars)
during digestion, absorbed into the blood and assimilated into
cells for respiration.
Foods rich in sugars or simple (processed) carbohydrates give a
quick release of blood sugar. More complex carbohydrates give
a slower, more sustained release of sugars to the blood.
http://nutritiondata.self.com/facts/fast-foods-generic/8053/2

6. Compare carbohydrate, fats and proteins in
terms of energy storage.
Energy /100g Carbohydrates Fats Proteins
kJ 1,760 4,000 1,720
kcal (Calories) 421 956 411
Fats are a highly efficient store of energy as they contain long-
chain fatty acids, made with many carbon atoms. During the
link reaction of respiration, pairs of carbon atoms are
transported into the Krebs cycle and used to produce ATP.
So… long chains + lots of carbons = lots of energy storage.
They are easier to build than they are to break down, though!
http://nutritiondata.self.com/facts/fast-foods-generic/8053/2 http://en.wikipedia.org/wiki/Triglyceride

7. Compare carbohydrate, fats and proteins in
terms of energy storage.
Energy /100g Carbohydrates Fats Proteins
kJ 1,760 4,000 1,720
kcal (Calories) 421 956 411
Proteins are long-chain polymers of
amino acids and contain carbon
atoms. They can be used for cell
respiration, though they are harder
to metabolise than lipids or
carbohydrates.
http://nutritiondata.self.com/facts/fast-foods-generic/8053/2 http://en.wikipedia.org/wiki/Protein_(nutrient)

8. Reading Food Labels
Calculate the % Calories from fat in this burger.
Calculate the % fat by weight in the burger.
http://nutritiondata.self.com/facts/fast-foods-generic/8053/2

9. Reading Food Labels
Calculate the % Calories from fat in this burger.
(295/563) X 100 = 52.4%
Calculate the % fat by weight in the burger.
http://nutritiondata.self.com/facts/fast-foods-generic/8053/2

10. Reading Food Labels
Calculate the % Calories from fat in this burger.
(295/563) X 100 = 52.4%
Calculate the % fat by weight in the burger.
(33/219) X 100 = 15.1%
Why “99% Fat Free” could be a lie…
http://nutritiondata.self.com/facts/fast-foods-generic/8053/2 http://www.youtube.com/watch?v=yd9XnyNGXGs

11. http://click4biology.info/c4b/a/A2.htm

12. Staple diets vary by geographical region and culture
Food staples are the main source of dietary energy for a population.
http://click4biology.info/c4b/a/A2.htm
Geographical Region/ Culture Main food energy source
Continental Europeans, USA
UK & Northern Europe
Central Africa & Brazil
Americas & Africa
Asia
Eskimo Tribes
Isolated Island Populations

13. http://cdn.wfp.org/hungermap/

26. Exercise & Energy
“How many calories are in your favorite foods?
How much exercise would you have to do to
burn off these calories?
What is the relationship between calories and
weight?
Explore these issues by choosing diet and
exercise and keeping an eye on your weight.”
PhET Lab: Eating & Exercise http://phet.colorado.edu/en/simulation/eating-and-exercise
You can try Wolfram | Alpha too.
What does it say about your favourite
forms of exercise?

50. http://goo.gl/lVUjr

51. Image: 'untitled'
http://www.flickr.com/photos/28025847@N05/7694792428
Found on flickrcc.net
@IBiologyStephen Please consider a donation to charity via Biology4Good.
Click here for more information about Biology4Good charity donations.
This is a Creative Commons presentation. It may be linked and embedded but not sold or re-hosted.