Eating & Weight

Question 1

How to calc BMI?

Answer 1

weight / height

Question 2

History of BMI

Answer 2

• supposed to be average man
• never intended to be a measure of health
• adopted by insurance companies
• 1985 became the official means
• misdianoses obesity 50% of the time

Question 3

Better measurements

Answer 3

• water displacement
• hip-to-waist ratio
• tape measures and skin calipers
• bodyfat scales
• hydrostatic weighing
• CT and MRI

Question 4

Genetics

Answer 4

• 70% of variance in BMI bc genes
• set point weight
  metabolic rate (how many cals at rest)
• tendency to store fat or muscle

Question 5

General Fat cells

Answer 5

• determines weight
• childhood determines (# of fat cells) bc stays static

Question 6

Krouple-like-Factors

Answer 6

dicates white fat cells
- importnat in determining how body deals with fat cells

Question 7

Brown fat cell

Answer 7

converts chemical E to heat to protect against cold

Question 8

Beige fat cell

Answer 8

immature cell in white fat tissue > matures ti burn fat

Question 9

White fat cell

Answer 9

most common, found under skin and abs

Question 10

Hypothalamus

Answer 10

regulates hunger, thirst, body temp. and sex drive

Question 11

Areas of the hypothalamus / hunger in the brain

Answer 11

• ventromedial nucleus (VMH)
• arcuate nucleus
• lateral hypothalamus (LH)

Question 12

General Arcute nucleus

Answer 12

• responds to circulating levels of energy related hormones and sends signals to VMG and LH
• centre for neuroendocrine function

Question 13

VMH

Answer 13

satiety centre

Question 14

LH

Answer 14

Hunger centre

Question 15

AgRP/ NPY neurons & POMC neurons

Answer 15

actiavted when body needs energy, act in opposition

Question 16

POMC neurons

Answer 16

signals to body to stop food intake and start burning energy (Leptin)

Question 16

Arcuate Nucleus Hormones

Answer 16

• Ghrelin
• Leptin
• AgRP
• POMC
  -NPY: increase food intake
  -MC4R: binds and leads to appetite suppression
  -α- MSH: acts on MC4R

Question 16

AgRP/ NPY neurons

Answer 16

Ghrelin: hunger hormone

Question 17

Absorption Phase

Answer 17

• digets
• absorb nutrients
• immediate & future needs
• full stomach
• increase blood glucose
• insulin release
• lipids increase
• leptin release

Question 18

Fasting Phase

Answer 18

• after absorption phase
• empty stomach
• ghrelin release
• low glucose
• insulin reduction
• reduced lipids and leptin

Question 19

Hunger in the Brain

Answer 19

• Absorption and fasting work in opposition

Question 20

Blood Glucose

Answer 20

• E source for cells of the body and brain

Question 21

E storage in the absorbtion phase

Answer 21

sugars & carbs > glucose > glycogen

fats > fatty acids > trigglycerides

proteins > aminio acids > proteins

Question 22

E release in fasting phase

Answer 22

Glycogen > glucose

Triglycerides > Fatty acids/ ketone bodies

Protein > amino acids

Question 23

Hyperglycemia

Answer 23

too much glucose and insulin (diabetics)

Question 24

Hypoglycemia

Answer 24

too little glucose

Question 25

ketosis

Answer 25

reduced eating of carbs > low glucose and insulin > fat burning increases > liver breaks down fat to ketones > ketones released into blood stream > brain uses ketones for E instead of glucose

Question 26

Dieting

Answer 26

- slows metabolism and function - increased avtivation in parts of brain that orient you to food and decreased activity in the PFC - as you lose fat, levels of leptin decrease and ghrelin increases

Question 27

Ozempic/ Wegovy

Answer 27

Semaglutide: feel less hungry pancreas promotes insulin secretion > cardiovasc sys decreases glucose > liver inhibits production of glucagon > stomach lowers appetite

Question 28

What is the physiological role of GLP-1?

Answer 28

↑ satiety ↑ nausea ↑ insulin ↑ insulin sensitivity ↓ hyperglycemia ↓ lipid accumulation

Question 29

What is the physiological role of GIP?

Answer 29

↑ insulin ↑ glucagon ↓ food intake ↓ hyperglycemia

Question 30

Conclusions of dieting

Answer 30

non-dieters eat based on hunger not cog, social or emotional factors

Question 31

Attentional Myopia

Answer 31

when cog resources are low, people focus on most salient feature of environment

Question 32

How does stress affect weight?

Answer 32

Stress blocks energy storage and mobilizes stored energy (lots of blood glucose) > SNS is activated via CRH to supress appetite If E not used then we store as visceral fat > cardiovascular damage

Question 33

Why do some people eat more and some people eat less under stress?

Answer 33

2/3 become hyperphagic 1/3 become hypophagic

Question 34

Why do some people become hyperphagic and others hypophagics?

Answer 34

- rel balance between SAM (less appetite) and HPA (creates appetite) activation (mediated by CRH and cortisol) - timing of stressor - indv differences in activation and recovery

Question 35

Excerise

Answer 35

- increases appetite and body adapts - muscles burn more cals - 2.5h of moderate aerobic/ week for adults

Question 36

Physio changes when exercising

Answer 36

- stronger cardiovasc - increased flexibility - stronger bones - improved immunity - promotes growth of new neurons

Question 37

Stress and exercise

Answer 37

- reduces adrenaline and cortisol in the LR - releases endorphins - sense of mastery