A2 Energy in Human Diets

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Energy in Human DietsStephen Taylor

Assessment Statements Obj

A21 Compare the energy content per 100g of carbohydrate fat and protein 3

A22 Compare the main dietary sources of energy in different ethnic groups 3

A23 Explain the possible health consequences of diets rich in carbohydrates fats and proteins (Explain consequences of excess of each separately) 3

A24 Outline the function of the appetite control centre in the brain 2

A25 Calculate the body mass index (BMI) of a person from their weight and height 2

A26 Distinguish using the BMI between being underweight normal weight overweight and obese 2

A27Outline the reasons for increasing rates of clinical obesity in some countries including the availability of cheap high-energy foods large portion sizes increasing use of vehicles for transport and a change from active to sedentary occupations

2

A28 Outline the consequences of anorexia nervosa 2

Assessment statements from Online IB Biology Subject GuideCommand terms httpi-biologynetibdpbiocommand-terms

httpnutritiondataselfcomfactsfast-foods-generic80532

What is food energy and how can it be measured Food energy from carbohydrates proteins fats Units food calories (kcal) or kilojoules (1kcal = 418kJ)

1 food Calorie = 1000 calories

SI unit kilojoules1 food Calorie = 41kJ (kilojoules)

As humans are autotrophs we take energy from food in form of carbohydrates lipids or proteins

(1 calorie = the energy required to raise the temperature of 1g water by 1oC)

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httpnutritiondataselfcomfactsfast-foods-generic80532

Compare carbohydrate fats and proteins in terms of energy storage

Energy 100g Carbohydrates Fats Proteins

kJ 1760 4000 1720kcal (Calories) 421 956 411

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httpnutritiondataselfcomfactsfast-foods-generic80532

Compare carbohydrate fats and proteins in terms of energy storage

Energy 100g Carbohydrates Fats Proteins

kJ 1760 4000 1720kcal (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

httpnutritiondataselfcomfactsfast-foods-generic80532

Compare carbohydrate fats and proteins in terms of energy storage

Energy 100g Carbohydrates Fats Proteins

kJ 1760 4000 1720kcal (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

Sohellip long chains + lots of carbons = lots of energy storage They are easier to build than they are to break down though

httpenwikipediaorgwikiTriglyceride

httpnutritiondataselfcomfactsfast-foods-generic80532

Compare carbohydrate fats and proteins in terms of energy storage

Energy 100g Carbohydrates Fats Proteins

kJ 1760 4000 1720kcal (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

httpenwikipediaorgwikiProtein_(nutrient)

httpnutritiondataselfcomfactsfast-foods-generic80532

Reading Food LabelsCalculate the Calories from fat in this burger

Calculate the fat by weight in the burger

httpnutritiondataselfcomfactsfast-foods-generic80532

Reading Food LabelsCalculate the Calories from fat in this burger

Calculate the fat by weight in the burger

(295563) X 100 = 524

httpnutritiondataselfcomfactsfast-foods-generic80532

Reading Food LabelsCalculate the Calories from fat in this burger

Calculate the fat by weight in the burger

(295563) X 100 = 524

(33219) X 100 = 151

httpwwwyoutubecomwatchv=yd9XnyNGXGs

Why ldquo99 Fat Freerdquo could be a liehellip

httpclick4biologyinfoc4baA2htm

httpclick4biologyinfoc4baA2htm

Staple diets vary by geographical region and cultureFood staples are the main source of dietary energy for a population

Geographical Region Culture Main food energy source

Continental Europeans USA

UK amp Northern Europe

Central Africa amp Brazil

Americas amp Africa

Asia

Eskimo Tribes

Isolated Island Populations

httpcdnwfporghungermap

Exercise amp Energy

httpphetcoloradoeduensimulationeating-and-exercise

ldquoHow 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 weightrdquo

PhET Lab Eating amp Exercise

You can try Wolfram | Alpha too

What does it say about your favourite forms of exercise

httpgoogllVUjr

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IBiologyStephen

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