Genetic Link to Alcoholism and Obesity: A New Study in Molecular Psychiatry

[Monique]

You're right

 

[selfAdjoint]

So, terminology apart, it can be done? Water, oxygen and glucose into fat?

I know the chemical pathways are probably beyond me (I googled before I asked - didn't get a clear answer). But that is what I'm really asking about; the body really can create fat (I guess fatty acid) molecules out of those precursers alone?

 

[Gelsamel Epsilon]

http://en.wikipedia.org/wiki/Lipogenesis

 

[Curious3141]

So, terminology apart, it can be done? Water, oxygen and glucose into fat?

I know the chemical pathways are probably beyond me (I googled before I asked - didn't get a clear answer). But that is what I'm really asking about; the body really can create fat (I guess fatty acid) molecules out of those precursers alone?

Most commonly, "fat" in the context of the human body refers to neutral fats, which are triglycerides (triacylglycerol). So we have to account for one molecule of glycerol (3C) and three molecules of fatty acids (which can have varying carbon chain lengths).

Very simplistically,

First glycolysis,

1) Glucose (6C) --> 2 Glycerol (3C)

2) Glucose (6C) --> 2 Pyruvate (3C)

3) Pyruvate (3C) + Coenzyme A (CoA) --> Acetyl (2C)-CoA + CO2 (1C)

Then fatty acid synthesis :

4) n AcetylCoA --> Fatty acid (2n C)

Then triglyceride synthesis :

5) Glycerol + 3 Fatty acid --> Triacylglycerol

 

[Monique]

So, terminology apart, it can be done? Water, oxygen and glucose into fat?

It's not terminology, I gave you the answer. The pathway is de novo lipogenesis that turns excessive carbohydrates into fat. But I don't think this is a significant pathway. The body rather uses carbohydrates for energy than fat, so with an excessive intake of carbohydrates your body will start to metabolize those and stores your dietary intake of fat for later use.

 

[Renge Ishyo]

Well, genetic disposition to eat or not, the fact of the matter is that one cannot become obese unless they have access to the food that makes them so. Even if it becomes proven fact that the tendency towards obesity is in some way strengthened by the function (or lack therof) of certain genes that control metabolism, fat cell generation, hormone secretions or whatnot you'd still have to admit that ultimately the food a person eats is at least partly responsible for their final condition. How many obese people do you see in some of the poorer nations, like India or Africa? Not too many, regardless of what genetic predispositions they may or may not have (ultimately, you can't get fat without the food!).

In the USA you see all sorts of freakish new diet related diseases such as diabetes affecting more and more people these days. Someone might analyze the situation and present a paper saying "Oh, these people seem to have some genetic defect that prevents the proper levels of insulin production". They might be right scientifically, but this doesn't take into account the possibility that the *cause* for something like type II diabetes is poor diet over the course of several several years. What if the same can be said for people who are later found to have "genetic dispositions towards obesity?" The question I have is, were they really born with it or did these isolated "genetic defects" develop after 10-15 years of neglect...

 

[Gelsamel Epsilon]

It's true, that you can't get fat if you don't have the food. But some people can't get fat if they don't have the genes. Take me for example, I happen to be lucky enough to eat all I want and I never put on weight! This is the whole point of the Genetic-Enviromental model of phenotypes. Sure you can say "without the food they won't get fat" but you can't say "food is therefore the soul cause of obesity" because there are other factors. This is in no way a scapegoat to blame something on something obese people can't control this is a way to understand obesity better so you can better treat it.

 

[Renge Ishyo]

I don't even understand what this debate was about anyways. Even if the link to genes becomes proven fact, it's not like we can treat it by mutating someone's DNA. It still comes down to treating it by making better choices when it comes to diet and exercising since those are the only potential causes that anybody can do anything about.

Epsilon, I was a garbage disposal when I was in my early 20's. Now, I so much as look at a piece of cheesecake and I gain 4 lbs...I guess this is just the way it is with most people when they get older and their metabolism slows down (of course now I can blame it on my faulty genetics instead of my age ).