Thursday, November 3, 2011

its been a while- wow + a rant on thermodynamics

We all know the laws of thermodynamics dont we? Im the first to admit that the more i learn about thermodynamics the less I understand – its the same with quantum physics, i know i should understand the collapse effect upon measurement... but i dont.
But saying that we get fat because we eat more calories than we use is just as helpful and informative as saying that there is a traffic jam because there are more cars on the highway than are leaving it. Yeah.... but why? How can we fix this so that traffic (metabolism) would flow smooth? I think we would need to understand the basics of trafficplanning. It aint actually such rocketscience.
All of this stating of the first law gets me reeling, I mean, any highschoolstudent knows that the 1st Law is only useful in a closed system. And a human organism is what then??

I will take a loan from Robert McLeod:
A human organism is:
  1. Not in thermal equilibrium with their environment. Last time I checked I have a body temperature around 38 °C and spend most of my time in 21 °C rooms.
  2. Capable of significant mass flows (e.g. respiration).
  3. Capable of sequestering entropy (e.g. protein synthesis).
In order to understand the extreme complexity of calculating energyequilibrium in open systems (accounting in enthropy) i have to take a loan from enthropyproduction blog:

In a recent thread i asked if anybody knew the difference between the physical measurement for energy used to heat water (calorie) and a bioenergetic calorie. In bioenergetics, for example, one usually looks at the Gibbs Free Energy, G rather than the internal energy, E. G includes the effect of entropy from the second law, it is a potential, a possibility for something not a must.  When you throw something off a tower in true Galileo style then its potentian energy (G) is converted into movement energy and reaches 0 on groundlevel. What happens to that energy? Is it adsorbed by the ground? But the ground doesnt heat from the impact of a pebble???

Being a biochemist and a natural scientist overall, I find the misinterpretation of the first law irksome and destructive. Lets figure in the second law of enthropy for open systems. (we all know there are 3 second laws right – closed, semiclosed and open)

In a closed system, the total quantity of energy does not change. Energy may change forms, but the total amount remains unchanged. The issue isn't the violation of this law (as in calories in doesnt equal calories out) it's whether all energy inputs and outputs are accounted for. Its weather the second law is taken into account.

Lets get to the open system – the human body.

In human metabolism we can talk about a “metabolic advantage” of lowcarb diets. Yes i can hear Colpo, Bray et al screaming in my mind. But just pick up a biochem textbook and there it is. Gluconeogenesis. Im shure we all know by now that we can make our own carbs. Why dont we then realise that that uses energy? If you have glucose ready in lood/liver then you take it into use at no energycost. If you dont it will cost you 6ATP to convert protein into glucose by GNG. So there goes a cal is a cal once again.

Ok, ok you say, but this is such a small amount of energy and is not statistically significant and
the body will still store excess energy in fatcells and you will get fat you say. Just as simply as if you excercise and diet you will lose weight. Riiight.

This is what a metabolically healthy body will do when it recieves excess energy: it ncreases futile cycling. Futile cycles are what give us our body temperature of 98.6 degrees. Futile cycles are just what the name implies: a cycle that requires energy yet accomplishes nothing. One example of such cycling is this: the body doesn’t use fat or glucose directly as fuel. We convert those into ATP. How? This is so F****ng complicated i will not even try to translate this from my brain which doesnt work in english... All i can muster is a quote from a textbook:
ATP is made from adenosine diphosphate (ADP) in an enzymatic structure called ATP synthase, which is a sort of turbine-like structure that is driven by the electromotive force created by the osmotic and electrical difference between the two sides of the inner mitochondrial membrane.” The turbine converts ADP to ATP by protons rushing from high-proton side to the lowproton side. The energy to accomplish that comes from the food we eat. That energy is broken down into elecrtons which give off energy and pump the protons along... at the end of this process the electrons attach to oxygen and form free radicals. This process is for some reason called uncoupling. We need something to control this or otherwise we could be making too much ATP from overeating and basically boil to death from the inside. In order that this wouldnt happen we have pores through the inner mitochondrial membrane where protons can drift through as the concentration builds too high and by proteins called uncoupling proteins that actually pump the protons back across. So we expend food energy to pump protons one way, then more energy to pump them back.
One of the things that happens on a high fat diet is that the body makes more uncoupling proteins. So, with carbs low and fat high, the body compensates, not by ditching fat in the stool, but by increasing futile cycling and by increasing the numbers of uncoupling proteins and even increasing the porosity of the inner mitochondrial membrane so that more protons qould be pumped and more energy “wasted”.
There are different uncoupling proteins and all of them have a different job. The one we are interested in here is UCP3. I know people here are fairly familiar with Krause`s leptin rx, and thus know that a healthy leptin signalling pathway is necessary in order for this UCP3 to do its job. If it doesnt excist – these futile cycles WILL NOT WORK. And you will just keep producing energy and storing it also. Untill you die of obesity. It will not matter if you will eat only 1000kcal per day and excercise every day – all you eat is stored from the secont that insulin hits the bloodstream. And it is kept in storage because of the scarsity of the gatekeeper, hormone-sensitive lipase, and the deafness of the receptors. Period. If you dont fix the pathways the cal in will always = cal stored. And if your metabolism is healthy then cal in = energy production + excess cal out as heat from futile cycles.

Oh fuck – i hope i have explained something and not made too many enemies. And i hope you get past my spelling mistakes. Ive got some work to do today also so Im in a hurry :)

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