Physiology of Eating - L8

1. DNA methylation is very dynamic during embryogenesis

2. happens in response to many factors, including in utero nutrition -> may permanently alter offspring gene expression 

3. gestational under- and overnutrition leads to hypomethylation of IGF2 gene

4. increased expression of IGF2 leads to increased growth of tissues 

insulin also plays a role in protein metabolism -> to high amount of protein in the diet is associated with risk of obesity

1. culture: we are getting used to like what we eat 

2. sweet taste receptors: 1 receptor for many sweet substances

3. bitter receptor: widely expressed throughout the body -> mediate diverse non-tasting roles 

4. genetic differences (polymorphisms) in receptors also account for individual differences 

1. at age 18 months

2. = rejection of foods that are novel or unknown to the child

3. evolutionary beneficial mechanism: help children avoid ingesting noxious of toxic chemicals (happens primarily in the visual domain)

4. children prefer the food they know (safety) -> new + potentially harmful food is avoided 

1. poeple learn to like what they're used to eat -> repeated exposure increases liking and intake

1. while eating the same food, the palatability decreases 

2. promotes switching among nutrient sources & hence increased chance of balanced nutrition 

1. prenatal conditioning to liking foods does happen -> pre- and postnatal eating behavior of mothers does influence childs eating behavior postnatally -> leads to imprinting of preferences

2. children usually like the taste impresions they discovered during pregnancy & nursing later in life 

3. taste of BM is much more variable than taste of formula -> BF children have less neophobia & lower obesity risk 

1. wisdom of what we eat emerges as the ability to learn -> we are not equipped with a specific appetite for essential nutrients: only through learning! (but in this experiment only natural foods & no junk food was offered) 

2. general variety in diet increases acceptance of new foods in infants 

1. restricting children's access to palatable food produces the opposite -> as soon as they can, they will overeat 

2. parental control decreases the capacity of children to compensate for consumed energy -> if they received preload before meal, they are not really able to listen to their bodies (satiation etc.) 

3. Pleasure of good food is experienced immediately -> negative effects are far in the future

4. learning from role models! 

5. children eat more after watching TV Ads on facebook 

1. obsogenic diet in teen years -> increased reward sensitivity and decreased behavioral control -> less dietary self-regulation -> weight gain -> prefrontal cortex dysfunction & executive function impairment & risk of neuropsychiatric disorders 

2. western diet is correlated with neurobiological changes in hippocampus that may be related to the ability of these dietary components to impair cognitive function