Psychological control of eating

Question 1

The difference between appetite and hunger

Answer 1

• hunger is a physical pain we feel when we need food

- appetite is the decision-making process for food-seeking behaviour

Question 2

Main factors controlling appetite (2)

Answer 2

1) homeostatic control: ghrelin from the stomach activates the vagus nerve which acts on hypothalamus which communicates to higher brain centers to initiate eating behaviour. These eating behaviours will be based upon previous experiences i.e. we will avoid foods we found horrible and seek out foods we found particularly rewarding
2) hedonic factors: social cues, emotions, for pleasure

Question 3

Evolutionary adaptation for eating behaviour: food pleasure cycle, energy density preferences

Answer 3

• food pleasure cycle: we will seek out foods which have brought us pleasure in the past- works on the limbic system
• we will be drawn to foods which are naturally more energy dense as we have evolved a species to be more comfortable being slightly overweight and satiated than under-weight and hungry

Question 4

The effect of acute versus chronic stress on appetite

Answer 4

• acute stress: will inhibit gastric emptying via corticotropin releasing factor. This reduces postprandial accomodation and meal tolerance
• chronic stress: activates the hypothalamus via the hypothalamic-pituitary-adrenocortial axis which increases cortisol, appetite and weight gain

Question 5

Impact of early life stressors on eating behaviours later in life

Answer 5

• stressors in early life can reduce tolerance to stress later in life
• eat more kcal rich foods when older and stressed

Question 6

Obesity: why it occurs, altered biology, why is isn’t your fault

Answer 6

• occurs due to increased food cues in Western society, easy access, reduced PA
• altered biology: reduced satiation from food, heightened gastric emptying, higher gastric volumes, can consume more food/min
• not our fault as evolutionarily have adapted to try and conserve energy and be as inactive as possible

Question 7

Behaviour modification therapies for obesity

Answer 7

• CBT
• acceptance based approach to behaviour and eating
• success rate low: <20%

Question 8

Description of eating disorders: Anorexia, Bulimia, Binge Eating, Restrictive food intake disorder

Answer 8

• anorexia: pathological fear of weight gain, body dysmorphia, excessive weight loss and restricted food intake. Dieting behaviour becomes habitual and part of their personality. They also tend to have more OCD personalities
• bulimia: binge- purge cycle, accompanied with increased anxiety and shame
• binge eating disorder: bingeing with all the guilt of bulimia but no purge
• restrictive food intake disorder: reduced interest in food, cutting out food groups due to perceived intolerance (but no underlying biological mechanism for why that could be). This can lead to extreme weight loss and risk of malnutrition

Question 9

Treatment of eating disorders

Answer 9

• important to recognise that will have altered gut biology (functional dyspepsia symptoms) with ED which needs to be managed
• Track bloods for signs of RFS
• nutritional counseling
• family therapy
• Psychological/psychiatric therapy
• CBT
• body image therapy

Question 10

Feeding disorders in children

Answer 10

• rare, 1-5%
• this is where child will restrict intake to 5-10 different foods
• more often just that the mother is overly anxious
• psychological therapy offered- success rate of 90%