This is a bit of a shame but they do.
If you eat fewer calories each day and don't pay attention, you will slow down.
The basal metabolic rate slows in an effort to conserve energy.
Your body thinks you might be starving.
It isn't really under conscious control.
This is important to realise because if you aren't aware of this you might not understand what happens.
Your body's basal metabolic rate is a little like a thermostat on a boiler.
If you are more active the rate goes up and you burn more fuel.
If you become less active, the basal metabolic rate slows down.
This is a survival feature.
There is no point burning through the calories at the rate needed for hunting and gathering if what the body is doing is sitting quietly because there is a famine or drought.
If supplies are scarce, you will need to sit around and make your stores last for as long as possible.
So your basal metabolic rate slows if you are sedentary and if there isn't much food going in the top end.
It makes sense.
If your body has slowed a little it will encourage you to want to sit around to try and burn fewer calories.
This is OK, because this is only a signal.
Just a message.
Like all messages, this one can be ignored.
You can stay active, you can even increase your activity levels.
Your body will cope.
The point is that if you don't think about this, you might eat less, slow down, burn less, need less and then wonder why you aren't losing the inches off your waistline.
The key is to realise this will happen and be ready for it.
Keep doing stuff.
Restrict your intake but stay active.
This will work.
Your body will try to alter your activity set point.
You have energy stores to spare.
Use your super-powerful brain to take charge and override the signals which will try to get your behind back in the comfy chair.
You will feel the appeal.
You won't want to get up - but the great thing is that once you are up and about doing stuff, the body is fine with it.
It is like a grumpy teenager.
It will not do anything without a severe kick up the butt.
But once it is up and about it can move about perfectly well.
More another day...