http://www.sciencedaily.com/release...81207133815.htm

It's not that complex, really. Feed an organism the wrong food and plenty of things are bound to go wrong.

From The Times
London, UK
15 December, 2008


Compulsion to overeat is mainly in the genes, study shows

The genetic roots of obesity lie mainly in the brain, according to research that implicates inherited eating tendencies as one of the strongest influences over waistlines.

The discovery of seven genetic variants linked to obesity has suggested that DNA affects body shape mainly by changing eating behaviour, rather than by regulating fat storage.

Of the seven, five seem to be active in the brain, making it likely that work by fine-tuning appetite, the sense of fullness after eating, or even preferences for some foods over others.

The findings indicate that although genetic differences can help to explain why some people are overweight while others are slim, obesity cannot generally be blamed on genes that slow metabolism and allow fat to be laid down more easily.

Most of the genetic factors linked to obesity, which were found by two independent research teams, seem rather to work by altering the amount people eat. Some DNA profiles may simply make it easier or harder to control food consumption.

This insight demonstrates how nature and nurture are intertwined in the origins of common biological effects such as obesity. It is also encouraging for therapy, as it means that something people can control – their food intake — is ultimately responsible for weight gain even when genetic predisposition is also involved.

“In cases like this, the line between nature and nurture begins to blur,” said Kari Stefansson, of deCODE Genetics, an Icelandic company that conducted one of the studies. “Genetic factors seem to be influencing environmental risk factors.”

Joel Hirschhorn, of the Children’s Hospital, Boston, who led the other study, by the international Genetic Investigation of Anthropometric Traits (Giant) consortium, said:“The genes near these variants are all active in the central nervous system, suggesting that inherited variation in appetite regulation may have something to do with predisposition to obesity.”

Genetic factors are known to influence obesity risk, as twin studies have shown that 40 to 70 per cent of the variation in body mass index is inherited. But it was only 18 months ago that scientists identified a first genetic variant involved, in a gene called FTO. The discoveries, published in Nature Genetics, bring the total number of variants firmly linked to obesity to nine.

All seven variants were detected by the deCODE study and six were also identified by the Giant consortium. Each of the variants has a modest effect on obesity risk. The 1 per cent of people who have the riskier version of all of them would typically be 2kg (4lb) heavier than an average person, and 4.5kg (10lb) heavier than a person with the least risky genetic profile.

http://www.timesonline.co.uk/tol/li...icle5342552.ece

From the Telegraph
London, UK
15 December, 2008


Six new obesity genes discovered

Obesity may be pre-programmed into the body claim scientists after they identify six new genes which predispose their carriers to becoming heavily overweight.

The vast majority of the newly discovered genes appear to cause carriers to eat more, rather than affect their body's ability to process fat, researchers believe.

The discovery could help scientists develop new ways to turn off impulses in the brain that make some people overeat.

Almost one in four Britons is now classed as obese and the proportion is expected to increase dramatically in coming years, alongside a rise in related diseases including heart disease and some forms of cancer.

Scientists looked at the genes of more than 90,000 people and uncovered six genetic variants associated with an increased Body Mass Index (BMI), the standard measurement of obesity.

Of the six, five are active in the brain, and could affect behaviour around food, rather than how the body breaks down fat or uses up energy, according to the findings, published in the journal Nature Genetics.

"It might seem remarkable that it is the brain that is most commonly influenced by genetic variation in obesity, rather than fat tissue or digestive processes," says Dr Ines Barroso, a senior author on the study, from the Wellcome Trust Sanger Institute. "Until 2007, no genetic associations had been found for 'common obesity', but today almost all those we have uncovered are likely to influence brain function."

Scientists hope that by analysing the genes they can better understand how they work and develop ways to tackle the problem.

Carriers with all six of the genes would be an average of almost five pounds overweight, the scientists estimate, and some much heavier.

In the brain the hypothalamus, which controls many of our basic functions, is programmed to maintain the status quo.

"Very occasionally, mutations in genes active in the hypothalamus have dramatic consequences for weight gain," explains Dr Ruth Loos, a leading author from the Medical Research Council Epidemiology Unit, "such that people carrying these mutations are severely obese. Such mutations might be considered exceptional.

"However, we suggest that the picture for common obesity is very similar: many or most genes associated with increased BMI are active in the brain."

Experts believe that genetic could account for between 40 and 70 per cent of the variation in BMI.

One obesity gene previously identified, FTO, is thought to be present in almost 60 per cent of the population.

The scientists estimate that up to dozens similar variants remain to be discovered.

"As we uncover more variants, we will gain a better basic understanding of obesity, which in turn will open doors to previously unimagined areas of clinically relevant research," said Joel Hirschhorn, from Harvard Medical School.

"We hope that these advances will guide the development of more effective treatments and interventions." Earlier this week scientists found that FTO caused carriers to eat an average of more than 100 extra calories per meal than non-carriers.

BMI is a ratio of weight to height. It is calculated by dividing a person's weight in kilograms by their height in metres squared.

http://www.telegraph.co.uk/health/h...discovered.html

How in the hell can these people *not* be aware of what causes most obesity?

Yes, a certain amount of obese people are probably victims of some sort of faulty genetic wiring, especially the uber obese (I'm talking TLC documentary obese here) who simply seem unable to stop eating no matter what dietary path they follow.

Since I've read GCBC though, I've become hyper-aware of how little talk there seems to be in the mainstream medical community about the hormone component to obesity. Guess that makes them insulin resistant! It's always 'genetic' or that goddamned 'calorie in, calorie out' unmerry-go-round! No wonder Dr. Atkins became so frustrated.

As Taubes shows in GCBC, here was a Cornell trained Cardiologist (Atkins) who had replicated success thousands of times in his own clinic and because of the sloppy science of Ancel Keys et al and the politically correct notions of the day he was treated like a pariah. I think the greatest test of maturity and integrity is the ability to admit that you were wrong....Dean Ornish, we're waiting!

So Michael Phelps is not obese because it's not his genes telling him to stuff himself, it's just a personal choice. If I'm overweight in this case it is because my genes tell me to overeat.

So when I eat low-carb, eat more calories and for the first time in my life succeed in losing weight and maintaining, what is the role of this gene that's telling me to eat more again?

EDIT : And for those* tempted to blame my weight on sedentary behaviour, please be aware that I was a national level tennis player in my teens, training 6 days a week, 4 hours a day, while still carrying a lot of extra fat. Was I eating 6000 calories a day or something?


* hypothetically speaking, of course no one on this forum would think such a pathetic thought.

Genes are merely the plan. The plan can change according to the environment i.e. what we eat. The earlier it is in our development, the easier it is to change the plan i.e. in the mother's womb. The plan can change because it contains provisions for those changes. It's not stuck in rut. If it were, we would be completely healthy even though our mother eats a boatload of carbage during pregnancy. Obviously, that's not what happens. We would be completely healthy unless we believed that our genes were programmed to build us crooked. Do we believe that?

A priori, genes tell us to grow perfectly healthy and perfectly formed. The alternative is that genes tell us to grow unhealthy and deformed.

We overeat to store excess nutrients and energy for the night period when we sleep. We are hyperphagic by nature. It must be written in our genes somewhere. It's not a surprise to find genes that tell us to overeat.

Carbohydrates cause us to eat more carbohydrates. Carbohydrates cause us to overeat. Considering how carbohydrates affect insulin and how insulin affects fat cells (and by extension bloodstream nutrients availability), that's not a surprise either.

Those researchers are merely discovering the mechanisms that explain our nature. They have yet to explain our diseases.

Exactly. I thought I was genetically programmed to overeat and be fat, but all that changed when I was diagnosed with type 2 diabetes. I soon came to my senses and got on low carb after years on Weight Watchers. Now it's much easier to control my cravings. I think genetics play a part, but you can overcome genetics with low carb.

EDIT : And for those* tempted to blame my weight on sedentary behaviour, please be aware that I was a national level tennis player in my teens, training 6 days a week, 4 hours a day, while still carrying a lot of extra fat. Was I eating 6000 calories a day or something?


Oh, absolutely! I was 222 lbs while cycling daily and working a very physical hotel job. The key phrase? Hotel job. Surrounded by carb rich food everyday. But no matter what regimen I follow I always seem a bit predisposed to the tendency to over-eat (and yes, better to 'over-eat' protein than carbs) although lc has changed that dramatically for me. Perhaps lingering appetite control damage brought on by years of over-carbing? Could over-carbing switch on some primal gene and ,in some cases, leave it on that leads people more prone to binge eating?