shadowplay Posted November 8, 2007 Posted November 8, 2007 I believe obesity is largely genetic. I've noticed some people have a much stronger psychological reaction to food than others. These are the people who usually become overweight. Food is like a drug to them. I know if I didn't control my weight to an extreme I'd probably fall into that category. I used to binge for days on food (mostly sweets) and then crash diet to get the weight off. I never purged because I have a fear of throwing up. I would literally eat over 10,000 calories in one day -- It was terrible. My mom has the same problem so I either inherited it from her or have learned to mimic her behavior (or both). But I guess the desire for me to stay thin and attractive is usually strong enough to counteract my impulse to binge. However, I think once you're already overweight it becomes like a slippery slope. It's much harder to motivate yourself once you're already over the hill.
uniqueone Posted November 8, 2007 Posted November 8, 2007 I believe obesity is largely genetic. I've noticed some people have a much stronger psychological reaction to food than others. These are the people who usually become overweight. Food is like a drug to them. I know if I didn't control my weight to an extreme I'd probably fall into that category. I used to binge for days on food (mostly sweets) and then crash diet to get the weight off. I never purged because I have a fear of throwing up. I would literally eat over 10,000 calories in one day -- It was terrible. My mom has the same problem so I either inherited it from her or have learned to mimic her behavior (or both). But I guess the desire for me to stay thin and attractive is usually strong enough to counteract my impulse to binge. However, I think once you're already overweight it becomes like a slippery slope. It's much harder to motivate yourself once you're already over the hill. I disagree with obesity being genetic. Are you saying that APPETITE is genetic? Have to disagree with that one too. That said, I dont think everyone's the same in regards to appetite control. I think some people are more impulsive and more drawn to the endorphin high of eating.
tanbark813 Posted November 8, 2007 Posted November 8, 2007 I disagree with obesity being genetic. Agreed. Just take a look around the next time you're in line at the grocery store. Almost invariably you'll see fat people buying soda and cookies and fit people buying veggies and foods high in protein.
luvmy2ns Posted November 8, 2007 Posted November 8, 2007 Agreed. Just take a look around the next time you're in line at the grocery store. Almost invariably you'll see fat people buying soda and cookies and fit people buying veggies and foods high in protein. Yep. It's totally a matter of choice and willpower.
shadowplay Posted November 9, 2007 Posted November 9, 2007 Yep. It's totally a matter of choice and willpower. I mean genetic in the behavioral sense of course. People who desire food more often pass that down to their children. Appetite.
tanbark813 Posted November 9, 2007 Posted November 9, 2007 I mean genetic in the behavioral sense of course. People who desire food more often pass that down to their children. Appetite. Everyone has an appetite. It's a biological instinct to motivate us to hunt down food.
uniqueone Posted November 9, 2007 Posted November 9, 2007 Agreed. Just take a look around the next time you're in line at the grocery store. Almost invariably you'll see fat people buying soda and cookies and fit people buying veggies and foods high in protein. And why is it that the fat people are always buying the regular soda and I'm buying diet!
shadowplay Posted November 9, 2007 Posted November 9, 2007 Everyone has an appetite. It's a biological instinct to motivate us to hunt down food. Yeah, but some people have more of an appetite than others and I think it's partly genetic.
uniqueone Posted November 9, 2007 Posted November 9, 2007 I mean genetic in the behavioral sense of course. People who desire food more often pass that down to their children. Appetite. So I would think then that you'd see those with the genetically larger appetite famished as infants. Since infants grow as a fast rate and require a lot of food per body weight, that would mean that they'd be eating constantly which would either mean that they'd be permanently attached to their mother's breast or walking around with a bottle attached to their mouths. However...I pretty much see infants acting about the same appetite wise......with a slight variation---but no variation by family...more so a variation by individual. This means that the weight gain happens later on....as behavior patterns get shaped. An infant eats until it's full and then stops. An older child relys on other cues....such as a parent telling them when to eat and how much....or a parent praising them for cleaning their plate.....or a parent promising them some sweets if they behave....or a parent taking their kids out all the time to fast food places and restaurants and encouraging huge portions. THAT is how weight gain gets passed along in a family. It's not due to anything genetic. It's due to behavior patterns that teach a child to use food for something other than nutrients.
shadowplay Posted November 9, 2007 Posted November 9, 2007 So I would think then that you'd see those with the genetically larger appetite famished as infants. Since infants grow as a fast rate and require a lot of food per body weight, that would mean that they'd be eating constantly which would either mean that they'd be permanently attached to their mother's breast or walking around with a bottle attached to their mouths. However...I pretty much see infants acting about the same appetite wise......with a slight variation---but no variation by family...more so a variation by individual. This means that the weight gain happens later on....as behavior patterns get shaped. An infant eats until it's full and then stops. An older child relys on other cues....such as a parent telling them when to eat and how much....or a parent praising them for cleaning their plate.....or a parent promising them some sweets if they behave....or a parent taking their kids out all the time to fast food places and restaurants and encouraging huge portions. THAT is how weight gain gets passed along in a family. It's not due to anything genetic. It's due to behavior patterns that teach a child to use food for something other than nutrients. I don't think you can rule out genes without looking at the literature. Anecdotal evidence doesn't suffice. If you look at twin studies, genes definitely play a role in obesity. I think it's a combination of genes and learned behaviors. Nature + Nurture. Specifically, some people are naturally less sensitive to insulin and low insulin sensitivity is linked to obesity.
shadowplay Posted November 9, 2007 Posted November 9, 2007 It's easy to find strong evidence of a genetic basis for obesity by simply doing a pubmed search. I will copy and paste some abstracts: Division of Epidemiology, Stockholm Centre of Public Health, Sweden. BACKGROUND: Eating behavior may be implicated in the increasing prevalence of overweight and obesity, presumably in relation to easy access to energy-dense and highly palatable foods. OBJECTIVE: The aim of the present study was to disentangle genetic and environmental influences on eating behavior in a population-based cohort of male twins. DESIGN: The study included 326 dizygotic and 456 monozygotic male twin pairs aged 23-29 y from Sweden. The revised 21-item version of the Three-Factor Eating Questionnaire (TFEQ-R21) was used to assess eating behavior. This validated instrument consists of 3 dimensions: cognitive restraint, emotional eating, and uncontrolled eating. Structural equation modeling was used to estimate the heritability of eating behavior. RESULTS: Cognitive restraint was the only TFEQ-R21 scale that significantly correlated with BMI (r = 0.39, P < 0.0001). The best-fitted models gave a heritability of 59% (95% CI: 52%, 66%) for cognitive restraint, 60% (95% CI: 52%, 67%) for emotional eating, and 45% (95% CI: 36%, 53%) for uncontrolled eating. CONCLUSIONS: These results show the great importance of genetic factors in the eating behavior of a large, unselected population of young adult male twins. Nonshared environmental factors were also important, whereas shared environmental factors did not contribute to eating behavior. PMID: 15755823 [PubMed - indexed for MEDLINE] Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Santiago, Chile. [email protected] This review focuses on methodological aspects and main results of different family studies that have been conducted to assess the existence of a genetic contribution in human obesity. A genetic component in the etiology of obesity has been elucidated through specific study designs answering different research questions such as: a) Do obesity aggregate in families? b) Is there a genetic contribution to familial clustering? c) Is it possible to localize chromosomal regions that contain susceptibility genes to obesity? d) Is it possible to estimate the risk for developing obesity depending on the genotype profile in candidate genes? There are sufficient evidences indicating the existence of a moderate familial clustering of obesity defined as body mass index >/=30 with a stronger aggregation with more extreme values of body mass index. Twin studies have demonstrated that the familial aggregation of obesity has a genetic component and is not only due to cultural or environmental factors clustered in families. Linkage studies have identified markers and genes related to obesity in virtually all human chromosomes. However, some of these linkage studies have produced conflicting results. Discordant results are even more pronounced in case-control studies that evaluate the association between alleles at candidate genes and obesity. Topics related to study design will acquire increasing importance in order to avoid methodological problems related to trait definition, sample sizes, population stratification by ethnicity and other confounding factors. PMID: 15880191 [PubMed - indexed for MEDLINE] Department of Neurlogy, University of Washington Sleep Disorders Center at Harborview, Box 359803, 325 Ninth Avenue, Seattle, WA 98104-2499, USA. [email protected] STUDY OBJECTIVES: To better understand the relationships of insomnia, sleepiness, and obesity. DESIGN: Classic twin study. SETTING: A community-based twin registry in Washington State. PATIENTS OR PARTICIPANTS: One thousand forty-two monozygotic and 828 dizygotic twin pairs participating in the University of Washington Twin Registry. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Twins were, on average, 32 years old; 61% were women, and 19.5% were obese, defined as a body mass index > or = 28. Insomnia and sleepiness were endorsed by 19.3% and 3.7% of twins, respectively. Twin correlations were higher in monozygotic than dizygotic twins for insomnia (0.47 versus 0.15), sleepiness (0.37 versus 0.14), and obesity (0.82 versus 0.46). Heritability estimates were 57% for insomnia (p < .001; 95% confidence interval 47-63), 38% for sleepiness (p < .01; 95% confidence interval 16-46), and 73% for obesity (p < .001; 95% confidence interval 49-87). Multivariate genetic model fitting revealed that common additive genetic effects comprised 12.8% of the phenotypic correlation between insomnia and sleepiness (p < .01) and 10% of the phenotypic correlation between insomnia and obesity (p < .01). The phenotypic correlation between sleepiness and obesity was not due to common additive genetic effects. CONCLUSIONS: Insomnia, sleepiness, and obesity are under strong genetic influence. Common genetic effects were observed between insomnia and both sleepiness and obesity, suggesting shared genetic contributions to these phenomena. PMID: 16774154 [PubMed - indexed for MEDLINE]
uniqueone Posted November 9, 2007 Posted November 9, 2007 The study isn't saying that obesity is genetic. It's saying that there's a possible correlation between insomnia, daytime sleepiness and obesity. Aside from that factor, one--or two studies---does not a theory make. Please show me several true identical twin studies which show a direct link between genetics and obesity.
shadowplay Posted November 9, 2007 Posted November 9, 2007 The study isn't saying that obesity is genetic. It's saying that there's a possible correlation between insomnia, daytime sleepiness and obesity. Aside from that factor, one--or two studies---does not a theory make. Please show me several true identical twin studies which show a direct link between genetics and obesity. See this quote from the insomnia/obesit study. "Heritability estimates were 57% for insomnia (p < .001; 95% confidence interval 47-63), 38% for sleepiness (p < .01; 95% confidence interval 16-46), and 73% for obesity (p < .001; 95% confidence interval 49-87)." That means the authors found a MAIN EFFECT of heritability on obesity independent of the other two factors (insomnia and sleepiness). The study also looked at INTERACTIONS between the three factors and found some, but that's not the part of the study we're interested in. The first study I linked to IS a true twin study. The second abstract is a review that compiles the results of many different twin studies.
uniqueone Posted November 9, 2007 Posted November 9, 2007 See this quote from the insomnia/obesit study. "Heritability estimates were 57% for insomnia (p < .001; 95% confidence interval 47-63), 38% for sleepiness (p < .01; 95% confidence interval 16-46), and 73% for obesity (p < .001; 95% confidence interval 49-87)." That means the authors found a MAIN EFFECT of heritability on obesity independent of the other two factors (insomnia and sleepiness). The study also looked at INTERACTIONS between the three factors and found some, but that's not the part of the study we're interested in. The first study I linked to IS a true twin study. The second abstract is a review that compiles the results of many different twin studies. That's not how I understood it. The study shows the affects of the three on each other.
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