Why do you think it is impossible? I failed to lose weight on a ~1200 kcal/day diet for several years of relatively active lifestyle. Does that seem impossible to you as well?

And then I kept more or less the same kcal intake (from the labels, which I don't find trustworthy, but I don't have any other source), but I dropped anything grainy (corn, wheat, rice), and lost 30 pounds within one month. Does that sound impossible to you? After those 30 pounds, my weight stabilized, and started rising again very slowly (2 pounds over a few months)

And then following some parts of the "The Bulletproof Diet", I went to ~2500 kcal/day, (about twice what I had before, mostly fat), and started losing weight again, at about 1 pound/week. Does that seem impossible to you?

When I called out the wrongness of "caloric balance" in another thread, you said "well, that's true but it doesn't matter, you should observe inputs vs. outputs". Which is true, and is correlated, but very far from being inferable from the caloric balance.

Yeah, I would think that's impossible. I'm going to just state user error as the leading cause here for your inability to lose weight. Unless you're completely unique in some shape or form such that reducing your caloric intake also reduced your BMR down to basically 0 (i.e. dead), I'm going to have to call bullshit.

My ex was an MD. At some point she told me "well, I'm going to eat what you eat for a few weeks to show you that you must be eating more than you think" (She was studying for exams, and we actually ate almost every meal together for a few months). She started having blackouts after a few days, continuously feeling starved, and stopped the experiment after less than two weeks.

What did she do afterwards? put a big SEP field over the experiment (and my food input). What did other nutritionists and doctors I consulted say? One called me a lier (about a few things; all of which -- except my food intake -- I was able to prove him wrong). Another said I should start eating meat (I'm vegetarian) - not because I'm missing anything, but because he couldn't find enough relevant statistics to compare me to.

My BMR _was_ reduced, but I didn't have enough money at the time to spend on getting it tested. But my body temperature in those years was ranging between 35.2 and 36.2 celsius (normal is 36.7) -- obviously I generated much less heat.

Just about _everything_ you know about medicine and nutrition is statistics that works for 90% of the population 99% of the time. I'm (un?)lucky to be stuck in the 1% of the time and 10% of the population in many respects.

I'm not sure if I should be annoyed or amused of how religiously people tend to assume nutrition and medicine are hard sciences like math and physics. (See my long reply to jacques_chester above for deconstructing his popular argument)

"I used to eat <X>, now I eat <Y> and <delta Z>. Where is your precious net calories now!"

Well this leaves us with two alternatives:

1. Something in biological systems is capable of defying the conservation of matter and energy. Somewhere in the spaghetti bowl, matter or energy are being wicked away or added in a fashion so subtle that it has never, ever been observed.

2. You measured incorrectly.

Nothing personal, but I know which hypothesis I will back.

(Also note the careful use of the qualifying phrase long term average weight to account for the general noisiness of weight).

However, there's more than two options, because "I eat X" doesn't necessarily mean "at BMR which would not vary with diet, I metabolically convert X at the caloric density listed on the label for the macronutrients involved."

A cup of black coffee has 5 kcal. Surely you would agree that consuming 1200 kcal/day of just coffee for 6 months (if you somehow survived) would lead to a different weight delta than consuming 1200 kcal/day of, say, non-dairy cream substitute?

> Somewhere in the spaghetti bowl, matter or energy are being wicked away or added in a fashion so subtle that it has never, ever been observed.

Well, being that I'm anonymous, you are welcome to think that I measured incorrectly, (and whatever else you come to think of). I accept that.

However, the statements I quoted above indicate that you're following religion while you believe you have a scientific world view. So, I will not try to convince you of my measurements (which I admit could be very erroneous, even though they are based on food labels, which are an accepted, if idiotic, method of measurement).

However:

There is NO law of conservation of matter or mass. If you believe there is one, you should revisit your physics; There is conservation of energy, (and depending on how your system is modeled, probably momentum as well). But no such thing as conservation of matter or mass.

There IS a law of conservation of energy, but it does NOT in any way apply to the question at hand -- except at the tautological sense which I pointed in the first place. To wit:

1. Cellulose (paper, wood) is a carbohydrate. You can eat 1kg of paper a day, which is thus assumed to have 4000kcal, and all the vitamins you need, plus 20 gram of protein (a suboptimal, yet generally livable diet) - and you will die of starvation. Yet, exchange the paper with 1kg of sugar, and you won't die of starvation (you will eventually of diabetes).

Now, if this "energy balance" you allude to meant anything in this context, the paper<->sugar exchange would not have made a difference. But it does. And the reason that it does is that enzymes in our body know how to break up sugar, but not cellulose - and cellulose, DESPITE ITS ENERGY CONTENT, gets out the same way it came in. So atwater (the guy who set up the food energy system we now use) added a "per food factor" to say how much we can derive from it, and paper gets 0. Great - but it has been shown (see below) that his numbers are far from precise.

Furthermore, the 4kcal/edible carbohydrate gram is available only through cellular respiration (oxidation). However, the body can get energy through fermentation (glycolisys) as well (which it does under some oxygen stress conditions, and which is what many cancers do because their oxidation mechanism, the mitochondria, is borked). And fermentation produces about 1/8th of the energy that oxidation does.

Furthermore again, some energy production is "learned" - the first time you try to digest sorbitol or xylitol, you derive exactly 0 kcal/gram from them. After a few weeks, you max out at ~2.5kcal/gram. After a few months of not digesting either, you're back to 0 (I read conflicting reports, the minimum of which is 3 months, the maximum of which is over a year - but apparently, the required enzyme production eventually winds down when you do not need them).

Furthermore, atwater factors (the way all caloric content is computed these days) have been shown to be 20% wrong for nuts (and have similar errors for every other group that was tested recently; not many have been. atwater factors are now 140 years old. They're bad, but no better system has been devised).

So, "energy balance" is not a balance unless you know:

a) you know how much of your food is actually digested

b) you know how much of your energy production is done by respiration as opposed to fermentation (about 99% when you are healthy. But are you healthy?)

c) you know you are in a steady state for your diet (so that, e.g. you get 2.4 kcal/g from xylitol and not 1.2)

d) you know your so-called BMR (which is not constant, and is in fact dependent on your food intake)

e) know your biome and how it effects your food (about 10% of your weight, 1000% of your cells by number, and about 30% of your feces are bacteria that are not the same in other people. Do you know how to account for them?)

I could go on for hours. You're repeating misguided religious arguments, believing that you're speaking science.

I obviously can't measure anything, per your conclusion. But you should study your body chemistry/physics/biology better. Because your option (1) above implies significant misunderstanding.

References:

How labels are computed: https://en.wikipedia.org/wiki/Food_energy

One example of how imprecise this system is: http://www.foodnavigator-usa.com/Science/Study-Almonds-may-h...

I've spent some time among "ketards" and they ate much more fat than they did protein. I think the recommended ratio was around 80% fat vs 20% protein.