SM_147b: Etiology of Obesity

Question 1

Physical activity level is comprised of ____ and ____

Answer 1

Physical activity level is comprised of posture and spontaneous activity

Question 2

Resting expenditure ___ as fat-free mass increases

Answer 2

Resting expenditure increases as fat-free mass increases

Question 3

Resting energy expenditure and total energy expenditure are ___ in lean patients than obese patients

Answer 3

Resting energy expenditure and total energy expenditure are lower in lean patients than obese patients

Question 4

Lean people have lower ____, ____, ____, and ____ than obese people

Answer 4

Lean people have lower fat-free body mass, fat mass, resting metabolic rate expenditure, and total energy expenditure than obese people

Question 5

Lean individuals expend ___ energy sitting and ___ energy standing and ambulating than obese individuals

Answer 5

Lean individuals expend less energy sitting and more energy standing and ambulating than obese individuals

Question 6

Body weight stabilizes when ____ balances higher energy intake

Answer 6

Body weight stabilizes when higher energy expenditures balances higher energy intake

Question 7

In an obese macroenvironment, ____ is easy

Answer 7

In an obese macroenvironment, energy in > energy out is easy

Question 8

Physical activity level is comprised of ____ and ____

Answer 8

Physical activity level is comprised of posture and spontaneous activity

Question 9

Resting expenditure ___ as fat-free mass increases

Answer 9

Resting expenditure increases as fat-free mass increases

Question 10

Resting energy expenditure and total energy expenditure are ___ in lean patients than obese patients

Answer 10

Resting energy expenditure and total energy expenditure are lower in lean patients than obese patients

Question 11

Lean people have lower ____, ____, ____, and ____ than obese people

Answer 11

Lean people have lower fat-free body mass, fat mass, resting metabolic rate expenditure, and total energy expenditure than obese people

Question 12

Lean individuals expend ___ energy sitting and ___ energy standing and ambulating than obese individuals

Answer 12

Lean individuals expend less energy sitting and more energy standing and ambulating than obese individuals

Question 13

Body weight stabilizes when ____ balances higher energy intake

Answer 13

Body weight stabilizes when higher energy expenditures balances higher energy intake

Question 14

In an obese macroenvironment, ____ is easy

Answer 14

In an obese macroenvironment, energy in > energy out is easy

Question 15

Summarize the energetics of obesity

Answer 15

Energetics of obesity

• Obesity is caused by an imbalance in the energy equation
• Weight gain is composed of increased fat mass and fat-free mass
• Obesity is associated with an increased total energy expenditue (BMR and PAL)
• Body weight stability is achieved when caloric intake = caloric expenditure

Question 16

Intake matches energy expenditure under conditions of ____ lifestyle

Answer 16

Intake matches energy expenditure under conditions of moderate-active lifestyle

Question 17

Obesity is a ____

Answer 17

Obesity is a complex multifactorial chronic disease that develops from an interaction of genotype and the environment

Question 18

There is some ____ of body weight

Answer 18

There is some heritability of body weight

• Animal models: obese (ob) mouse (leptin deficient), diabetes (db) mouse (leptin resistant)
• Human inherited disorders: Prader-Willi syndrome, leptin deficiency, POMC deficiency, and melanocortin 4 receptor deficiency
• Adoption studies
• Twin studies
• Family metabolic studies

Question 19

BMI increases as number of ____ increase

Answer 19

BMI increases as number of obesity alleles increase

Question 20

Maternal weight is positively associated with ____

Answer 20

Maternal weight is positively associated with child’s risk of obesity

• Epigenetics: intrauterine environment alters DNA methylation and histone modification to change gene expression

Question 21

Obesity and pregnancy are associated with ____ and ____ that exacerbate in combination, increasing ____

Answer 21

Obesity and pregnancy are associated with insulin resistance and inflammatory changes that exacerbate in combination, increasing lipid transfer earlier in gestation

• Reversal of dietary weight gain is influenced by duration and severity

Question 22

In a high fat diet, neuron damage in hypothalamus results in ____ and ____ leading to ____

Answer 22

In a high fat diet, neuron damage in hypothalamus results in astrocyte activation and microglial activation leading to increased body weight

Question 23

Transmission of ____ determines leaness

Answer 23

Transmission of gut microbiota determines leaness

Question 24

Summarize the determinants of weight gain

Answer 24

Determinants of weight gain

• Obesity is caused by a multiplicity of factors: genetics, biology, habits, psychosocial, environmental influences
• Although monogenic obesity and syndromic obesity are prototypic, most common cause is polygenetic (multiple alleles)
• Obesity can be transformed to offspring by epigenetics: role and mechanisms of microbiota are uncertain
• Hypothalamic inflammation plays a role in persistence of chronic obesity

Question 25

_____ occurs when someone loses a lot of weight

Answer 25

Adaptive thermogenesis (metabolic adaptation) occurs when someone loses a lot of weight

• Regulated production of heat in response to environmental changes in temperatuee and diet -> metabolic inefficiency
• Help defend body weight

Question 26

Metabolic adaptation (adaptive thermogenesis) is primarily from ____

Answer 26

Metabolic adaptation (adaptive thermogenesis) is primarily from metabolic work efficiency of muscles

• Skeletal muscle work efficiency accounted for the majority of reduction in nonresting energy expenditure associated with weight loss - this is not significant with higher work loads

Question 28

Maintenance of an obese state is caused by ____ and perhaps ____

Answer 28

Maintenance of an obese state is caused by excessive caloric intake and perhaps lower PA + NEAT

Question 29

Energy requirements are higher in obesity due to increased ____ and overall higher ____

Answer 29

Energy requirements are higher in obesity due to increased fat free mass and overall higher total energy expenditure