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Module 31: Food

Recall our main themes: energy->water->food->culture

Food!

Three main groups: 

  • Proteins: always include Nitrogen
  • Carbohydrates: CHO in chains (starches) or simple (sugars)
  • Fats: CHO again, but in a special branch structure (glycol backbone) that is good for energy storage and insulation (e.g. killer whales, eskimos)

Proteins: complex molecules of CHO and N. 

  • Look up amino acids, note the common structure.
  • Now look up the amino acid methionine. 
  • What element does it contain as well? 
  • Why do rotten eggs, swamps (and Kilauea volcano) stink?

CHO=carbohydrates (clever name), 

  • usually in a chain, short chains are sugars (used for fuel), 
  • longer ones are starches and can be used for structures (e.g. cellulose in plants) or pasta...
  • smallest: sugars, all end in -ose (glucose, sucrose) LOOK THESE UP, CHECK OUT THEIR MOLECULE SHAPE
  • glucose is a "monosaccharide" created by photosynthesis
  • longer chains: starches (rice, pasta) slowly digested (see diabetics, and glycemic index)
  • structural CHO: cellulose-little boxes with goo inside, need enzymes to break these down (cows)
  • ENZYMES ALL END IN -ASE

Fats/lipids: same chemical structure as CHO, but built along a glycol (alcohol) backbone. 

  • If the fats have long carbon chains with only single bonds, they are saturated (lots of Hydrogen atoms) and can hold together (e.g. animal fat)https://en.wikipedia.org/wiki/Saturated_fat
  • If the long chains have double bonds and don't fit together, they melt easier (e.g. oils) and are called "unsaturated", usually better for your health.
  • n.b. McDonalds® got into real hot water a while ago for frying all of their stuff in "supersaturated fats". Ugh...

Notes: Chapter 11 FR Overview:

  • Frog 12.3 Agriculture
  • Frog 12.4 Food Production
  • Ch. 12 assessment
  • FR ch. 11 feeding the world
  • FR mod 31 nutritional needs
  • FR mod 32 industrial ag-insecticides, GMO
  • FR mod 33 sustainable farming
Big picture:
  • Trophic pyramids in nature are sustainable
  • Planet is nearing carrying capacity (K)
  • Think of how many "earths" your global footprint represents
  • To meet this food demand, current farming and fishing is industrial, not sustainable

Mod 31: Nutritional needs-what humans on our planet need, and what they lack
Read the case study p. 373-how is this like a trophic pyramid in nature?
  • Undernutrition: lack of calories
  • Malnutrition: lack of critical part of diet, usually protein (Kwashiorkor)https://en.wikipedia.org/wiki/Kwashiorkor
  • Food security: not just in lesser developed countries ("LDC"), also in the US"Food deserts"-what are these?
  • Famine: one of these impacting a large group, often from crop failure, drought or war/displacement
  • Overnutrition: common in the US, look up the US obesity rate-how is this determined? Why? Seen any food ads lately?
Look up US obesity rate-----
Meat diet: high in protein, also in fat (energy store) and cholesterol-these contribute to heart disease
  • Wait-Eskimos eat lots of blubber, why don't they have heart disease? 
  • How is this different from Kalahari bush tribes?Climate
  • Wait, wait-what happened to Japanese health care system when they moved from their traditional diet?
  • What impact does this have globally?
  • Diet for a small planet 1971: planet can sustain population using fewer calories while supplying protein, vitamins and calories. Not by relying on meat.Vitamins="vital amines"
Food energy subsidy (cost factor):
  • 20 kg of grain to produce 1 kg of beef (20:1 factor, or subsidy factor 20x)
  • 2.8 kg of grain to produce 1 kg of chicken (2.8:1 factor, or subsidy factor of 2.8)
  • Better to eat beef, chicken, fish or tofu? (you need protein in some form)

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