Question

^{The relative contribution of our genes and the influence of our diet and lifestyle to obesity has been the subject of numerous studies. As the rates of obesity in the adult population in the U.S. are approaching 40% (according to CDC), to find the answer to the question of nature vs. nurture in obesity is becoming extremely urgent.}  

^{In your post, explain in detail how nurture and nature can contribute to the development of obesity. What are the two most convincing pieces of evidence that both genetic and environmental factors play significant roles in the development of obesity? The answer must be at least 120 words with at least one references.}

Answer 1

The biological (nature) and psychological and behavioral (nurture) factors affect people leading to obesity.

Nature includes the neuroendocrine control of body weight which could be either short term or long term.

Short term signals involve various signals such as the hormones or peptides responsible for meal intakes such as ghrelin, amylin, cholecystokinin, Glucagon-Like Peptide 1 (GLP-1) and Oxyntomodulin

Long term control includes the levels of adiposity. hormones controlling the adiposity include Adiponectin, Insulin, Leptin, Neuropeptide Y and Pro-opiomelanocortin

Only 176 known cases of obesity have been linked to single-gene mutations in humans for eg: Prader-Willi syndrome (short stature, hypotonia, developmental delay) involves significant hyperphagia, as do Bardet-Biedl (short stature, developmental delay, retinitis pigmentosum, polydactyly) and Alstrom (blindness or vision loss, hearing loss, hyperinsulinemia) syndrome.

Gut microbiota: Theories linking obesity and gut microbes revolve around the bowel flora’s use of energy from ingested foods, bacterial fermentation of foods into readily absorbable fatty acids, and influences on metabolism in peripheral organs

Stress: Stress can result from multiple causes, e.g. sleep deprivation, malnutrition, depression, and environmental stressors such as poverty. These factors may be related to obesity risk, even in the prenatal period

Medications: glucocorticoids, oral glucocorticoids, anti-psychotics (risperidone, olanzapine, clozapine), mood stabilizers (lithium), anti-depressants (tricyclics), anticonvulsants (valproate, carbamazepine), oral contraceptives, and insulin and insulin secretagogues are the more commonly reported ones,

Endocrinologic conditions: Hypothyroidism, Cushing syndrome and Insulinoma are the various causes of obesity.

Pure genetic contributors to obesity, such as the mythical “fat gene”, are quite rare, there are many genetically linked causes that can increase a child’s risk of obesity.

NURTURE FACTORS OF OBESITY includes behavioral and psychological factors

Sedentary lifestyle include diet, industrialization and the built environment

Walkable neighborhoods and communities with sidewalks, safe intersections, accessible destinations, appealing green spaces, and public transit have improved activity levels and health can provoke the people for physical fitness and to manage the obesity

Prenatal causes of obesity include maternal diabetes, Maternal Malnutrition, and Famine, Maternal Smoking During Pregnancy and Maternal Weight and Pregnancy

Postnatal causes include Early Childhood Feeding and Parenting and Adiposity rebound

Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3224976/#R20