Basically, we all know kcals don't really matter. And we all know someone who, all things being as CW says they are, would need 3000kcal/day who manages on 2000kcal/day and someone who would need 1500kcal/day who needs 1800kcal/day. We all know that a 'calorie' as measured in a lab isn't translated directly into the fuel your body burns. Most of us are aware of the origins of the 2000kcal/day advice (Food Politics » Where did the 2,000 calorie diet idea come from?) and of the different ways the body processes kcals (There Is No Such Thing As A “Calorie” (To Your Body) - GNOLLS.ORG).
And we've all probably had days where, with no change to our regime, we fancied (and ate) far more or far less kcals than the day before.
I propose to you that, on a daily basis, your kcals can go up and down because dietary protein isn't energy. Hear me out. I know it can be transformed into energy. But think about it this way... (continued on blog)
[Posted it to the blog that I'm reviving.