Problem 6 – Bon appétit
Digestion:
- the primary purpose of hunger is to increase the probability of eating
- primary purpose of eating: supply the body with the molecular building blocks and energy it needs
to survive and function
- Digestion: gastrointestinal process of breaking down food and absorbing its constituents into
the body
- most of the work of breaking down the food is done by the constituent of ones gut microbiome
(the bacteria and other organisms that live inside ones gastrointestinal tract)
Energy:
- Energy is delivered to the body in three forms:
1. lipids – fats
2. amino acid – break down products of proteins
3. glucose – simple sugar that is the breakdown product of carbohydrates (starches and sugar)
- Energy storage in the body in three forms:
1. fats (biggest part) – a gram of fat can store almost twice as much energy as one of glycogen
2. glycogen
3. proteins
, Metabolism:
- three phases of energy metabolism
1. cephalic phase
→ preparatory phase, start: sight, smell or thought of food, end: absorption of food
2. absorptive phase
→ energy is absorbed into the blood stream – is meeting the bodies immediate energy needs
3. fasting phase
→ all the unstored energy from the previous meal has been used – body is withdrawing
energy from its reserves to meet the energy requirements
→ characterized by high blood levels of glucagon and low levels of insulin
- insulin and glucagon: control the flow of energy during the three phases of the energy metabolism
→ cephalic phase: function of insulin is to lower levels of bloodbrone fuels – primarily glucose
→ absorptive phase: function of insulin is to minimize increasing levels of bloodbrone fuels by
utilizing and storing them
- insulin is not required for glucose to enter most brain cells
Theories of Hunger and Eating
Set-Point Assumption
- assumption that when the levels of the body’s energy resources falls far enough below the set
point, a person becomes motivated by hunger to initiate another meal
- has three components:
• a set-point mechanism – defines the set point
• a detector mechanism – detects deviations from the set point
• an effector mechanism – acts to eliminate the deviations
- all set-points systems are negative feedback systems: systems in which feedback from changes in
one direction elicit compensatory effects in the opposite direction
Glucostatic Theory
- is a set point theory
- the eating is regulated by a system designed to maintain a blood glucose set point
→ we become hungry when our blood glucose levels drop significantly below their set point
- accounts for meal initiation and termination
Digestion:
- the primary purpose of hunger is to increase the probability of eating
- primary purpose of eating: supply the body with the molecular building blocks and energy it needs
to survive and function
- Digestion: gastrointestinal process of breaking down food and absorbing its constituents into
the body
- most of the work of breaking down the food is done by the constituent of ones gut microbiome
(the bacteria and other organisms that live inside ones gastrointestinal tract)
Energy:
- Energy is delivered to the body in three forms:
1. lipids – fats
2. amino acid – break down products of proteins
3. glucose – simple sugar that is the breakdown product of carbohydrates (starches and sugar)
- Energy storage in the body in three forms:
1. fats (biggest part) – a gram of fat can store almost twice as much energy as one of glycogen
2. glycogen
3. proteins
, Metabolism:
- three phases of energy metabolism
1. cephalic phase
→ preparatory phase, start: sight, smell or thought of food, end: absorption of food
2. absorptive phase
→ energy is absorbed into the blood stream – is meeting the bodies immediate energy needs
3. fasting phase
→ all the unstored energy from the previous meal has been used – body is withdrawing
energy from its reserves to meet the energy requirements
→ characterized by high blood levels of glucagon and low levels of insulin
- insulin and glucagon: control the flow of energy during the three phases of the energy metabolism
→ cephalic phase: function of insulin is to lower levels of bloodbrone fuels – primarily glucose
→ absorptive phase: function of insulin is to minimize increasing levels of bloodbrone fuels by
utilizing and storing them
- insulin is not required for glucose to enter most brain cells
Theories of Hunger and Eating
Set-Point Assumption
- assumption that when the levels of the body’s energy resources falls far enough below the set
point, a person becomes motivated by hunger to initiate another meal
- has three components:
• a set-point mechanism – defines the set point
• a detector mechanism – detects deviations from the set point
• an effector mechanism – acts to eliminate the deviations
- all set-points systems are negative feedback systems: systems in which feedback from changes in
one direction elicit compensatory effects in the opposite direction
Glucostatic Theory
- is a set point theory
- the eating is regulated by a system designed to maintain a blood glucose set point
→ we become hungry when our blood glucose levels drop significantly below their set point
- accounts for meal initiation and termination
