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
Short Food Chain
(Three Trophic Levels)
Third Trophic
Level
Wolf
(Carnivore)
Second Trophic
Level
Deer
(Herbivore)
First Trophic
Level
Grass
(Autotroph)
PYRAMID OF NUMBERS
BLUEGRASS PASTURE
BIRD
3
GRASSHOPPER
GRASS
708,624
5,542,424
CARNIVORE
HERBIVORE
AUTOTROPH
PYRAMID OF BIOMASS
BLUEGRASS PASTURE (LB/ACRE)
BIRD
1
GRASSHOPPER
GRASS
54
4,190
CARNIVORE
HERBIVORE
AUTOTROPH
PYRAMID OF ENERGY
LION
CARNIVORE
DEER
HERBIVORE
PLANT
AUTOTROPH
SOLAR
ENERGY
Energy Lost
1
10
9
90
100
10,000
CALORIES
9,900
CALORIES
Human Food Chains
• What do human do to increase available
energy?
– Humans generally shorten food chains and
make them simpler
• Shorter food chains -
Affect of Feeding at Lower Trophic Levels
Number of Adult Humans
Supported for a year
Adult
One
Human
600 Trout
180,000 Frogs
54 million Grasshoppers
2000 tons of Grass
Thirty
Nine Hundred
Two Thousand
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)
Caveats with Plant Based Diets
• Let’s eat grass!
• What kind of plants can we eat?
– High in digestible carbohydrates
(sugars and starches)
– Corn, wheat, rice , potato, sugarcane,
cassava (manioc)
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 AA’s
– Grains low in lysine
– Soybeans
• high lysine
• low in methionine
• Animal protein contains the essential AA’s
Comparison plant and animal proteins
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Food
Eggs
Fish
Chicken
Beef
Cow’s Milk
Brown Rice
Soybean
Wheat
Corn
Polished Rice
Manioc
Broccoli
Potato
Complete
Proteins
Incomplete
Proteins
Ranking
100
75
72
70
60
55
45
40
35
38
35
30
30
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
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
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
Energy Cost for Meat production
– Ratio: kcal of energy to produce a kcal of protein
• (kcal of fossil fuel: kcal protein)
• Beef
54:1
• Lamb
50:1
• Pork
17:1
• Turkey
13:1
• Chicken
4:1
• Grain
3.3:1
• One half of USA agriculture energy goes into livestock
• What percent of our fossil fuel do we import? 65%
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
Percent of Calories From Starch
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.”
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)
Annually
73,000
illnesses
Contaminated
Beef
63 death
Antibiotics
(subtherapeutic)
12-37%
Liver Abscesses
E. coli
0157:H7
In cattle
Increased
Rumen Acidity
“stomach ulcers”
Bacteria
(Fusobacterium necrophorum)
Enters the bloodstream
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
Animal Wastes
• Animal wastes generated are not treated
– 7 billion livestock in USA (livestock produced
20x’s as much waste as humans in the United
States)
Energy Cost for Meat production
– Ratio: kcal of energy to produce a kcal of protein
• (kcal of fossil fuel: kcal protein)
• Beef
54:1
• Lamb
50:1
• Pork
17:1
• Turkey
13:1
• Chicken
4:1
• Grain
3.3:1
• One half of USA agriculture energy goes into livestock
• What percent of our fossil fuel do we import? 65%
Fat in Our Diets
• Supplement to Vegetarian vs. Meat Diet
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
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
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
Structure of Fatty Acids
Omega 6 fatty acid
Methyl
Group
Double Bond
Acid
Group
Omega 3 fatty acid
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
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 LDL’s’ (Bad cholesterol) increase HDL’s
(Good Cholesterols)
– Ratio: Total/HDL –average 4.5
– Good ratio 2 to 3
• Slower cancer cell growth
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
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
Vegetarianism and Health
• Vegetarians have blood cholesterol levels:
– 14% less than non-vegetarians
– vegans are 35% lower
• Vegetarian’s 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
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
References:http://www.animalplace.org/why.html
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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 Dietitian’s 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 NonVegetarians: 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