lesson 8 Flashcards
hunter gatherer diets
Diverse, rich in fiber and micronutrients.
Seasonal and varied depending on geography.
agricultural diets
Reliance on staple crops (e.g., wheat, rice, maize).
Lower protein, vitamin content; higher risk of deficiencies.
industrial diets
Highly processed, high-GI foods.
Increased sugar, fat, and sodium intake.
three compnents of foods
proteins, fats (triglycerides), cabohydrates
poteins
Coiled chains of amino acids, used for
building and maintaining tissues
* Seldom used for energy
fats (triglycerdes)
three long fatty acid molecules bound to a
glycerol
* either stored as energy in the liver or in
adipocytes (in muscle) or immediately
burned
* 1 gram of fat = 9 calories
carbohydrates
Two common types:
* Simple sugars: can be burned
immediately or stored as fat, dumped
into blood stream
* Glucose – starchy, not too sweet
* Fructose – very sweet,
metabolized by liver – excess
converted to fat
* Complex sugars (polysaccharides)
broken down by digestion into simple
sugars
insulin
hormone produced in
pancreas to regulate blood
sugar levels and delivery of
energy within body
type 2 diabetes
cells don’t
respond to insulin, leading to
overproduction of insulin – blood
sugars rise causing heart disease,
vision loss, kidney disease
carrdioovascular disease
atherosclerosis (plaque buildup in
arteries)
wrangham cooking hypothesis
Cooking enhances nutrient availability, reduces digestion energy costs.
Amylase gene (AMY1)
Higher copy number in populations with starch-rich diets.
lactase peristence (LCT gene)
Multiple alleles evolved independently in Europe, Africa, and Asia.
Allows adults to digest lactose, conferring survival and reproductive advantages in dairying societies.
FADS genes
Influence fat metabolism; selected differently in farming vs. herding populations.
TEE - total energy exppenditure
= Basal Metabolic Rate (BMR) + physical activity + thermoregulation + digestion.
Studies show that foragers (e.g., Hadza) and Westerners have similar TEE when controlled for body size.
Obesity likely stems from increased energy intake, not decreased activity.
high-gi foods
spike blood sugar → insulin resistance → type 2 diabetes.
cardiovascular disease
linked to saturated fat, low fiber, and high sugar.
foood industrialization
increased processing and refined sugar (e.g., HFCS), altering nutritional content.
Nutritional Characteristics of Subsistence-level
(small-scale food producing) Human Societies
Fluctuations in food availability
* Marginal energy balance
* Limited availability of fat & simple carbohydrates* High level of Energy Expenditure & Physical Activity* No single ‘ideal diet’ – humans can eat almost
anything
* Basic tradeoff between protein fat / carbohydrates– Both, in certain context, can provide nutritious diet
dogs and startch adaptation
Dogs also adapted genetically to changing
diet
Increased copy number in dog pancreatic
amylase AMY2B relative to wolves
More changes in expression later in the
starch digestion pathway
triglycerrides
dietary fat found in
meats & dairy
* FADS1 and FADS2 involved in fatty acid
metabolism (plasma lipid and fatty
acid concentration)
* High triglycerides in blood: increased
risk of heart disease, stroke, metabolic
syndrome
* Most-selected allele (rs174546) >
decreased triglyceride levels
* “A critical component of adaptation to
different diets” (Mathieson, 2016)
glycemic index
measure of how quickly carbohydrates boost blood sugar
- boom bust cycles
- variety, ripeness, cooking methods, processing, length of storage all influence GI
fibre
encases cells that
contain sugars, delays
absorption, lowers GI –processing reduces fibre
a shifting energy balance
Traditional interpretations:
Lower activity, greater
intake through recent
human past = obesity
