This is such an oversimplification its not even funny, you don't even specify which off the thermodynamic laws you are talking about and how those specific laws relate to the metabolic system. The body is not a machine in the same manner as say a car, the human body in contrast to the car is a self regulating system. It does this through hormones such as insulin(funny that insulin is a fat storage hormone and also a culprit in diabetics). Not all calories are the same to the human body and they are metabolized differently, carbs cause much higher insulin spikes than fat does for instance.
It is a valid simplification. If you cannot see that you are incapable of rational, logic thought. I'm going to assume that's the case, but I'll give you a chance and elaborate on why it is that simple, and why your arguments are irrelevant.
The laws of thermodynamics are well-proven, and if you look them up it's easy to see which ones are relevant to this issue. They're very generic, and their consequences are more relevant than the laws themselves, mainly the implication that energy can not disappear, it can just move from one state to another. (
http://en.wikipedia.org/wiki/Laws_of_thermodynamics )
There's nothing magical about the body which makes it able to violate the laws of thermodynamics, yet you claim that without backing it up with anything.
My simplification is valid, because it allows for metabolic variance with calories from different sources.
Two extreme examples, assume a base metabolic rate of 2000 kCal per day, where the only variance is the diet, and that the figures for thermic effect I found for fat, sugar, protein hold in this individual, respectively 0%, 15%, 25%.
A: a diet where 2500kCal comes from 50% sugar and 50% fat.
Metabolic rate ends up at 2187.5, accounting for the thermic effect of the sugar.
The person has a calorie surplus of 312.5 kCal which has to go somewhere -> weight gain.
B: a diet where 2500kCal comes from 100% protein.
Metabolic rate ends up at 2625kCal accounting for the thermic effect of the protein.
The person has a calorie deficiency of 125kCal, which has to come from somewhere. -> weight loss.
As you can see from the examples; I know what I'm talking about, and that
my simplification is valid, because it simplifies both in and out. It's a simplification that has it's uses, and needs to be understood, because the balance between energy in and energy out is essential to understanding weight loss, weight gain, and weight balance. It is a magic bullet, but you can't use a bullet without a gun. Any method that results in weight loss works because of the implications given by this simplification.
The human body is a machine and can be studied as one. It is also a thermodynamic system and can be studied as one. It's more than a machine, but that does not mean it can't and shouldn't be studied as one when it's needed to understand what happens. Do you need to fully understand everything that happens in order to deliberately gain, maintain, or lose weight? No. But you have to, if you're to constructively debate causes of obesity.
By calling my valid simplification an oversimplification you've just proved that you lack understanding, and possibly the capability for rational thought. It is impossible to have weight loss without having a calorie deficiency when you add up the numbers for energy in and energy out.
It doesn't matter where the deficiency comes from, without it there's no weight loss. No matter if it's an artificially controlled deficiency from counting, or from a diet which makes it easy to have a deficiency.
