Invariably, if someone discusses dieting and weight reductions in public foras for long enough some of the regulars will show up:

• people honestly enthusiastic about this or that wonder vegetable or fruit
• people honestly trying to tell you that something quite ordinary is seriously bad for you
• people trying to sell something (and they might be disguised as one of the aboves)
• someone who knows enough physics to be dangerousannoying saying: it is really simple – calories in and calories out, that's what matters.

And the last one of them is right of course, because if it wasn't and anyone could prove it it would shatter our understanding of thermodynamics and probably physics in general.

But here's the catch: for many people, if they naively try to continue just as before just with 5% smaller meals, chances are not much will happen.

Realizing this might even puzzle a number of people who believe in calories in – calories out if they haven't thought about it closely yet. I'll try to briefly explain it below.

It just so happens that we are more efficient at making use of the food when there's less of it. I.e. when somebody overeats, a good deal of those extra calories leave the body undigested.

Which means for someone who is overeating they'll often have to reduce their calorie intake quite a bit more than they would expect as they are probably underestimating their current calorie consumption and/or overestimating their current activty levels.

This can be painful and feel seriously demotivating.

Once however one get below ones magic line, change will happen.

The draft for this post was written a couple of months ago but I wasn't happy with it (for good reason), and then things happened. I'll try to get around to saying something about that as well.