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Ecology of Meat Diet vs. Vegetarian Diet What do ecological principles tell us about availability of energy to humans? –Pyramids Summarize food chains.

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Presentation on theme: "Ecology of Meat Diet vs. Vegetarian Diet What do ecological principles tell us about availability of energy to humans? –Pyramids Summarize food chains."— Presentation transcript:

1 Ecology of Meat Diet vs. Vegetarian Diet What do ecological principles tell us about availability of energy to humans? –Pyramids Summarize food chains & Trophic levels Numbers Biomass Energy Energy loss in food chains

2 Short Food Chain (Three Trophic Levels) Grass (Autotroph) Deer (Herbivore) Wolf (Carnivore) Third Trophic Level Second Trophic Level First Trophic Level

3 PYRAMID OF NUMBERS BLUEGRASS PASTURE AUTOTROPH 5,542,424 708,624 3 HERBIVORE CARNIVORE GRASS GRASSHOPPER BIRD

4 PYRAMID OF BIOMASS BLUEGRASS PASTURE (LB/ACRE) AUTOTROPH 4,190 54 1 HERBIVORE CARNIVORE GRASS GRASSHOPPER BIRD

5 PYRAMID OF ENERGY SOLAR ENERGY PLANT AUTOTROPH DEER HERBIVORE LION CARNIVORE 1 10 100 10,000 CALORIES 9,900 CALORIES 90 9 Energy Lost

6 Human Food Chains What do human do to increase available energy? –Humans generally shorten food chains and make them simpler Shorter food chains -

7 Affect of Feeding at Lower Trophic Levels 2000 tons of Grass 54 million Grasshoppers 180,000 Frogs 600 Trout Human Adult One Number of Adult Humans Supported for a year Thirty Nine Hundred Two Thousand

8 Could we support more humans if we fed at lower trophic levels (ate more plants and less animals)? How many vegetarians can be fed on land needed to support 1 person eating a meat base diet? – Vegetarians (10-20) Acres needed to feed –non-vegetarian (4 acres) –vegetarian ( ½ acre or less)

9 Caveats with Plant Based Diets Lets eat grass! What kind of plants can we eat? –High in digestible carbohydrates (sugars and starches) –Corn, wheat, rice, potato, sugarcane, cassava (manioc)

10 What concerns are there with plant based diets? Plants provide calories May lack essential amino acids –Essential Amino acids 20-21 (9 or 10 we cannot synthesize) Plant protein –Typically lack 1 or 2 essential AAs –Grains low in lysine –Soybeans high lysine low in methionine Animal protein contains the essential AAs

11 Comparison plant and animal proteins Food Ranking Eggs100 Fish75 Chicken72 Beef70 Cows Milk60 Brown Rice55 Soybean45 Wheat40 Corn35 Polished Rice38 Manioc35 Broccoli30 Potato30 Complete Proteins Incomplete Proteins

12 Protein Consumption in Different Parts of the World How much protein does a person require? –Recommended Daily Allowance (RDA) –RDA per adult mixed diet = 56 grams –(RDA) is dependent upon body weight: – 0.8 grams of protein per kilogram (2.2 lbs) of body weight for adults 174 lb adult 63 grams of protein daily 138 lb adult 50 grams daily. –Protein consumption in different parts of the world

13 Livestock Production World-wide Enough grain produced to feed everyone - if distributed equally World-wide - major effort to increase livestock production 1950-1990 –Number of livestock tripled 5.3 to 15 billion –Chickens increased the most (3 to 11 billion) – Human population doubled How did the increase in livestock production occur? –Increase in grain and Agriculture energy allocated to livestock production

14 Grain and Energy Costs to Produce Meat Traditional livestock production –Animals turned things people could not eat into things they could eat Ruminants: cattle, sheep, goats –Grass, crop wastes Pigs and fowl –Cannot use grass –Use crop waste, kitchen scraps United States Meat Production –Grain is converted to livestock –Inputs used to produce one kg of meat, eggs, or cheese

15 Energy Cost for Meat production –Ratio: kcal of energy to produce a kcal of protein (kcal of fossil fuel: kcal protein) Beef54:1 Lamb50:1 Pork17:1 Turkey13:1 Chicken 4:1 Grain3.3:1 One half of USA agriculture energy goes into livestock What percent of our fossil fuel do we import? 65%

16 Conversion of plant to Animal Protein (USA) 41 million tons of plant protein to produce 7 million tons of animal protein –26 million tons grain –15 million tons grass Many people in the poor portions of the world cannot afford the luxury of converting grain to meat

17 Percent of Calories From Starch

18 Antibiotics Why add antibiotics to livestock feed? –4% increase in growth Annual Use of antibiotics: –Livestock 11-17 million pounds per year –Human 3 million pounds per year Why Worry About Livestock Use of Antibiotics? The Union of Concerned Scientists – overuse of antibiotics in intensive animal agriculture is a main contributor to the development of a myriad of new treatment-resistant pathogens afflicting both animals and humans.

19 Human Diseases, Antibiotics And Beef Range Fed Beef (3/4) 1.Grass and other forage crops 2.Microbes (bacteria adapted to forage) Feed lot (grain) 100 days (1/4) 1. Starch Digests More Quickly than Forage 2. Less cud chewing less saliva (one-half) Increased Rumen Acidity Bacteria (Fusobacterium necrophorum) Enters the bloodstream stomach ulcers Liver Abscesses E. coli 0157:H7 In cattle Contaminated Beef Annually 73,000 illnesses 63 death Antibiotics ( subtherapeutic ) 12-37%

20 Meat Diet (Summary of Concerns) Large amount of energy is need to produce meat Grain is converted to animal products so less grain is available for human consumption –Grain and soybeans fed to livestock in the USA: would feed 800,000,000 – 1,400,000,000 people –USA more than 50% of grain is fed to livestock –World wide 38-40% of grain is fed to livestock As world consumption of meat increases grain available to feed poorer nations declines

21 Animal Wastes Animal wastes generated are not treated –7 billion livestock in USA (livestock produced 20xs as much waste as humans in the United States)

22 Energy Cost for Meat production –Ratio: kcal of energy to produce a kcal of protein (kcal of fossil fuel: kcal protein) Beef54:1 Lamb50:1 Pork17:1 Turkey13:1 Chicken 4:1 Grain3.3:1 One half of USA agriculture energy goes into livestock What percent of our fossil fuel do we import? 65%

23 Fat in Our Diets Supplement to Vegetarian vs. Meat Diet

24 Kinds of Fats Saturated –Acid –C-C-C-C- C-C-C-Methyl Group –No double bonds between carbons Monounsaturated –Fatty acid with a single double bond –Acid –C-C-C=C- C-C-Methyl Group

25 Kind of Fats Polyunsaturated –Fatty acid with more than one double bond –Acid –C-C-C=C-C=C-C-Methyl Group Trans Fat - hydrogenated –Hydrogen added to the double bond carbons

26 What kind of fat should we consume? Small Amounts of Saturated fats (7%) of total fat intake Sources: whole-milk dairy products, fatty meats, tropical oils, partially hydrogenated vegetable oils and egg yolks Increase cancer and heart disease risk Unsaturated Fatty Acids –Essential Fatty Acids –Omega-3 and omega -6 Fatty Acids

27 Acid Group Methyl Group Omega 3 fatty acid Omega 6 fatty acid Structure of Fatty Acids Double Bond

28 Omega-6 Fatty Acids Omega-6 fatty acids –Source: Corn, safflower, sunflower, soybean, and cottonseed oil (cooking and baking oils) –Functions: Important for brain function, Stimulate bone and hair growth, necessary to maintain reproductive function

29 Omega 3 fatty acids Omega-3 fatty acids –grains, fresh fruits and vegetables, fish, olive oil, garlic –Functions: Cognitive and behavioral function Inflammatory diseases (osteo-arthritis) Reduce heart diseases Reduce LDLs (Bad cholesterol) increase HDLs (Good Cholesterols) –Ratio: Total/HDL –average 4.5 –Good ratio 2 to 3 Slower cancer cell growth

30 Ratio of omega-6 to Omega-3 Ratio of omega-6 fatty acids to omega-3 fatty acids –Good: one to four times more omega-6 fatty acids than omega-3 fatty acids –USA Diet: 11 to 30 times more omega-6 fatty acids than omega-3 fatty acids

31 Fat In Our Diets How much fat should we consume –30% of calories from fat – 7% saturated –2,000 calorie diet (600 calories) –12 calories/g of fat = 50 g (3.5 saturated) McDonald's Double Quarter lb with Cheese –Calories 770 –Fat 47 g –Calories from fat 430 (56%) –Saturated Fat 39 g

32 Vegetarianism and Health Vegetarians have blood cholesterol levels: – 14% less than non-vegetarians – vegans are 35% lower Vegetarians risk of dying from heart disease is less than half that of a non-vegetarian Medical costs in USA directly attributable to meat consumption - $60-120 billion Meat eaters have triple the rate of high blood pressure as compared to vegetarians The obesity rate: –General population 18%, –Vegans is 2%. Men who consume large amounts of dairy products have a 70% increased risk for prostate cancer

33 Things to think about 1.1 billion people world wide are over weight 1 billion people world wide have an inadequate diet 60 million people starve to death each year

34 References:http://www.animalplace.org/why.html 2. Resnicow, K., Barone, J., Engle, A., et all, "Diet and Serum Lipids in Vegan Vegetarians: A model for Risk Reduction," Journal of the American Dietetic Association 91 (1991): 447-453. See also Sacks, F.M., Ornish, D., et al., "Plasma Lipoprotein Levels in Vegetarians: "The Effect of Ingestion of Fats from Dairy Products," Journal of the American Medical Association 254 (1985): 1227-41 3.Resnicow, et al., "Diet and Serum Lipids in Vegan Vegetarians." See also Messina and Messina, The Dietitians Guide to Vegetarian Diets 4. Phillips, R., et al., "Coronary Heart Disease Mortality among Seventh-Day Adventists with Differing Dietary Habits," American Journal of Clinical Nutrition 31 (1978):S191-8; Burr, M., et al., "Vegetarianism, Dietary Fiber, and Mortality," American Journal of Clinical Nutrition 36 (1982):873-7 5. Halweil, Brian, "United States Leads World Meat Stampede," Worldwatch Issues Paper, July 2, 1998 6. Ophir o., et al., "Low Blood Pressure in Vegetarians...," American Journal of Clinical Nutrition 37 (1983):755-62; see also Melby, C.L., et al., "Blood Pressure in Vegetarians and Non-Vegetarians: A Cross-Sectional Analysis," Nutrition Research 5 (1985):1077-82 7. Mokdad, A., et al., "the Spread of the Obesity Epidemic in the United States," Journal of the American Medical Association 282 (1999): 1519-22 8.Health Professionals Follow-up Study, reported in "Dairy Products Linked to Prostate Cancer," Associated Press, April 5, 2000. 9. Washington Post: Gains From Antibiotic Ban Noted; Benefits to Danish Farm Animals Come at 'Marginal' Cost, March 27, 2002, David Brown


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