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Study Questions

1. Describe proteins (complete vs. incomplete), carbohydrates (simple vs. complex) and fats (saturated, unsaturated and trans) in the nutritional context.

2. Explain how much of one’s diet should come from proteins, fats and carbohydrates.

3. Compare and contrast the terms undernourished vs. malnourished.

4. Why do food shortages exist?

5. What are humans’ major food sources, and what problems arise in producing/harvesting these?

6. Discuss factors required for successful agriculture.

7. What is meant by the terms “green revolution” and “sustainable agriculture?” 1

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Food, Nutrition and Agriculture

Food and Nutrition

Food gives us:

•Energy

•Physical structure

• Vitamins and Minerals

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Basic Food Requirements

Approximately 2,000 calories per day

•Proteins (10-35%)

•Carbohydrates (40-60%)

• Fats (20-35%)

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Recommended Dietary Allowance for Protein

Grams of proteinneeded each day

Children ages 1 – 3 13

Children ages 4 – 8 19

Children ages 9 – 13 34

Girls ages 14 – 18 46

Boys ages 14 – 18 52

Women ages 19 – 70+ 46

Men ages 19 – 70+ 56

http://www.cdc.gov/nutrition/everyone/basics/protein.html

ProteinsCompete (whole): contain all essential amino acids

Incomplete: contain only some of essential amino acids

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Carbohydrates (sugars, starch, fiber)

•Simple Carbohydrates: single or double sugars (mono, disaccharides)

•Complex Carbohydrates: 3 or more sugars (polysaccharides)

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Single sugars include:

•Glucose•Fructose •Galactose

Double sugars include:

•Lactose•Maltose •Sucrose

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Complex Carbohydrates: (starch, dietary fiber)

•Legumes, starchy vegetables, whole-grains

Fiber requirement:14 grams per 1000 calories consumed

Chains of glucose molecules make up starch molecules and fiber (cellulose) molecules

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Fats (and Cholesterol)

Saturated: animal products

Unsaturated: nuts, vegetable oils, fish (omega-3, omega-6)

Trans fat: partially hydrogenated oil

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Cholesterol: “fatty” molecule in animal products

HDL: high-density lipoprotein cholesterol, or “good”

LDL: low-density lipoprotein cholesterol, or "bad"

Recommendation: <300 mg cholesterol per day

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Recent Diets in the Media

•Adkins (low carb)•Paleo (no grains, legumes, dairy, etc.)•Mediterranean (low red meat, sugar, fat)•Ornish (low fat)•Gluten-free

•And many others!

• In 1960, nearly 60% of people in developing countries were chronically undernourished

• World population has increased 1.7%; food production has increased 2.2%

• Less than 20% of people in developing countries now chronically undernourished

Food security: the ability to obtain sufficient, healthy food on a day-to-day basis

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Undernourished: insufficient calories

Over 850 million people suffer chronic hunger

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Why are people undernourished?

Current world food supply could support world population with 2200 kcal per day!

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Factors Contributing to World Hunger Include:

•Bad weather (drought, famine)

•Political instability

•Social crises

•Poverty

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Malnourished: imbalanced or insufficient nutrients

Malnutrition can lead to:

• Mental deficiencies

• Physical deficiencies

• Blindness

• Diabetes

• Cancer

• Heart attack

• Obesity 16

Overweight people now outnumber underweight people

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To be healthy, one needs a balance of both amount and type of food

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Food Sources

• Major Crops (wheat, rice, maize)

• Fruits/Vegetables

• Meat

• Seafood

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Wheat Rice

Corn Potatoes 20

More than 1/3 of world cereal is consumed by livestock animals

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Comparison of number of kilograms of grain needed to produce 1 kg of live weight gain

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Over-crowded livestock operations can contribute to:

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• air and water pollution

• antibiotic resistance

• infectious diseases

Seafood is also a major protein source

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Agricultural Essentials

• Soil: mixture of rock, live and dead organisms

Essential for plant life

Exposed to the elements

Subject to human priorities

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• Water

All plants need water to grow

Too little or too much can be harmful

Salinization (accumulation of salt) can be a problem

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• Fertilizer

Calcium, magnesium, nitrogen, potassium, phosphorus are often limited or absent in soil

Adding these nutrients via fertilizer increases crop yield

Can pose human health risks

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• Energy

Farming requires lots of energy!

Fossil fuels power farming machines

Distributing fertilizers, pesticides requires energy

Food must be processed, packaged, shipped, stored, etc.

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• Pest Control

Chemical pesticides Biological controls

Can kill non-target species Insect predators

Different organisms become pests

Create resistant pests

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The Green Revolution

• Increased crop yields due to synthetic fertilizers

• Cross-breeding plants for high-yield varieties

Conventional vs. “Miracle” Wheat 31

Sustainable Agriculture

Sustainable agriculture: just and lasting food production techniques (“regenerative farming”)

• Produce sufficient food to feed the world

• Minimize/repair damage caused by destructive farming practices

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Soil Conservation

• Reduce erosion

(terracing, contour plowing, strip-farming)

• Provide groundcover (cover crops, mulch)

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Natural, Agroecological Farming

• Small scale, low-input farms

• Less fertilizers, pesticides, etc.

• Reduced erosion

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