[squidgedcricket]

Glucose and ethanol are metabolized through different pathways that will have different efficiencies. How much impact does that have on comparing the two?

Glucose can go right into the bloodstream (?), but ethanol needs to be reacted (taking energy) to turn into blood glucose.

This is a confusion I have about calories-in-calories-out in general, fat/carbs/protein are all metabolized with different (and variable) efficiencies. Even pro-CICO folks agree not to count ingested calories that can't be metabolized, but that's just one spot on a gradient to draw a line.

[positr0n]

I know the efficiencies are variable among people and labels are not exact, but if you eat an amount of chicken breast labeled 100 calories, and an amount of butter labeled 100 calories, don't those numbers represent the amount of protein and fat respectively that the average person would absorb?

[Tarq0n]

Almost. Protein takes a bit more energy to metabolize than fat. It gets even more complicated when food contains indigestible fiber.

[ErikBjare]

I thought the energy needed to metabolize protein was included in the calorie estimation?