FS21
Fichier Détails
| Cartes-fiches | 14 |
|---|---|
| Langue | Deutsch |
| Catégorie | Biologie |
| Niveau | Université |
| Crée / Actualisé | 15.05.2021 / 08.06.2021 |
| Lien de web |
https://card2brain.ch/box/20210515_physiology_of_eating_l6
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| Intégrer |
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Positive vs. negative consequences of food
positive: experienced immediately
negative: less tangible, usually distant in the future
Flavor: (2)
1. major determinant of palatability -> rewarding effect of food
2. BUT: palatability is not inherent feature of food -> related to learning, upbringing, culture -> ppl eat food because tthey get used to like what they eat
Why do we prefer high fat/sweet foods? (5)
can partly be explained by sheer physiology:
1. D-glucose preferred fuel for neurons
2. low storage capacity for glucose
3. specialized sugar (=sweet) receptors
4. physiologically useful = high rewarding value
Taste cells encode behavioral responses (Experiment) (5)
human bitter receptors not expressed in mice and planted them in mice
1. control mice did not differ between water and bitter substance acting on this receptor
2. mice with bitter receptor in bitter cells -> low preference for bitter substance
3. mice with bitter receptor in sweet cells -> high preference for bitter substance
-> stimuli of sweet receptor cell produced preference behavior (its half-wired)
Liking vs. wanting
Liking: generated by small set of hedonic hotspots
Wanting: generated by large and distributed systems
Dopamine and reward (3)
unexpected reward: increase DA neuron activity after cue
expected reward: increased DA neuron activity simultaneously to cue
negative prediction error: no reward occurs -> increased DA neuron activity simultaneously to cue -> afterwards, weakening of positive association
2 roads to food reward (2)
1. Taste + oral somatosensation + retronasal olfaction
2. Subliminal reward signals generated during nutrient metabolism in gut
-> sweet (1) and sugar (2)
Is there evidence for "food addiction" or "eating addiction"?
(2)
1. repeated consumption of palatable foods (usually with high energy content) has features of addictive behavior
2. some evidence suggests that eating addiction may be associated with overweight/obesity -> but causality not unequivocally established yet
How does palatability increase meal size? (1)
- inhibitory signals act later -> later ending of the meal
Variety within a meal increases pleasure and meal size
(3)
1. our ancestors with no nutritional knowledge were dependent on mechanisms like this to survive (get enough nutrients)
2. variety in diet can also increase body weight
3. environment we're exposed to (continuous availability of palatable, energy dense foods) is problematic
conditioning (2)
learning (1)
neural stimulus (conditioned) paired with another stimulus (unconditioned) -> produces automatic response -> after repeated pairing, CS elicits response similar to unconditioned response
adaptive change in behavior that results from experience -> conditioning is a very simple form of learing
Condition + eating
Eating can be elicited in satiated rats & humans by conditioned stimulus (expected reward) -> we are exposed to MANY stimuli that can condition eating -> overweight/obestiy epidemic
Conditioning/Learning in food selection: (3)
hedonic experience is associated with the sensory properties of food -> influences food selection and appearance
-> positive effects that influence experience: pleasant surroundings, memories, satiating effects
-> negative effects that influence experience: unpleasant memories, diseases, stressors
-> sensory properties of food will then act as conditioned stimuli
Recommendations (4)
1. try modify behavior where possible (energy density, portion size, snacks, exercise)
2. no rigid control (-> counterregulation)
3. flexible control
4. less behaviora control & more situational prevention
