Read The Hacker's Diet a while ago, and it seemed reasonable to my old control-systems training. What's the current sort of counter-argument to the abstraction presented there?
One of those blog posts sparked exactly such a discussion -- that the body was "too complex" to be governed by mere physics.
The body is too complex to be governed by "mere physics", because it uses control systems that regulate the intake process.
I can eat three times more than a friend of mine, and incorporate to my body way less than my friend, because bacteria and virus in my intestines are completely different from hers. Also my body is different.
A calorie of fat has nothing to do with a calorie of sucrose or glucose.
"Mere physics" of burning something at 1000C and measuring the thermal output is completely different from the "real physics"of metabolizing substances in a 20 different steps chain process, where every step could be inhibited or excited by cell control systems.
Eg:
http://www.ncbi.nlm.nih.gov/pubmed/7869932
http://www.ncbi.nlm.nih.gov/pubmed/2082216
I remember talking to a (rake-thin) cousin of mine about this when we went to dinner one night. "I eat as much as anyone", he protested.
Later in the evening, noticed that while I had finished the chips that came with our dinners, he had not.
Your friend no more needs to know about your gut flora than you need to know about my insulin sensitivity.
The Hacker's Diet holds as an axiom that calories from fat, carbohydrate and protein are equivalent in this formula. This assumption neglects the powerful influence of the hormone insulin, which plays a key role in regulating fat metabolism. Insulin release is very highly correlated with carbohydrate consumption, and a diet that restricts carbohydrate will often lead to weight loss.
Problems with the Taubes' it's-all-carbs-and-insulin hypothesis:
* Protein consumption causes insulin spikes too.
* Insulin is not the only hormone involved in weight control system and energy system behaviour. Also involved: leptin, ghrelin, glucagon, cortisol and probably dozens of others neither of us will hear of in our entire lifetimes.
* Population obesity closely tracks calories-per-capita, apparently regardless of macronutrient breakdown (http://wholehealthsource.blogspot.com.au/2012/06/calories-st...).
That's part of the general Taubes carbs-insulin hypothesis; that insulin affects satiety (the feeling of fullness, or no longer wanting to eat).
As I said above, there are more hormones involved than insulin. For example, one very influential hormone is leptin. It has a profound affect on appetite and satiety; but we still only understand it poorly.
And leptin can be affected by all sorts of factors. Sleep deprivation, even small amounts, really play merry hell with it. Next time you're running on fumes, you may notice both that a) you're starving and b) your ability to resist the temptation to eat anything is greatly diminished.
And so on. The body is more complex than the thermodynamic equation, but ultimately that is enough to control your mass. The additional details are worth introducing as and when they are necessary (and a good dietitian will do that), but not before. People are very good at giving themselves excuses and, of course, analysis paralysis allows them to forestall any real change.