BMR

Basal metabolic rate (BMR) is the rate of energy expenditure per unit time 
by endothermic animals at rest.

This is the opening sentence of the Wikipedia article on the suject.
It is a benchmark figure.

The whole discussion is in calories.

It is used to do the accounting of body energy expenditure on categories
of chemical reactions in body, the analog to rent and utilities in one's
monthly household budget.

The numbers provide an estimate for an individual based on simple parameters
such as sex and age.

That said, one's BMR should not be taken as a diet guide by oneself. A health
practioner might look at it when helping a client adjust to a diet; that's it.
And it is not useful to someone watching Netflix from the couch:'Hey I'm burning
just sitting here, better do nothing.' BMR will compare a human to a snake in a
controlled environment, not an average woman to Jennifer Lopez day-to-day.

The dead don't burn calories, even though they are 'at rest'. One's body functions
kick-in with activity, so that an athlete at rest is someone who has been active
and has stopped; not someone first thing in the morning.

The focus of the measure is thermogenesis ie maintaining body temperature.
Indeed, the measure is taken on an animal 'not actively engaged' in digestion.

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An obese person in hospital awaiting an operation - at rest - might be
put on a very restrictive diets. Here in Quebec, fruit, bouillon, after a few days
rice and eventually chicken. If that doesn't work after 8 days, the cycle begins
again until the person is ready to be operated. That's how people are 'reset'.

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It is not my intention to be preachy. In fact, I think that many fail
at dieting becauses their brains aren't ready, they are overwhelmed.
No child, regardless of size, is capable of housework before the age of
twelve not because of lack of strength, but because their brains aren't ready.
They can play at housework with a parent, but they cannot do it, the
tasks are too complex. I fear that healthy eating may not be attainable at all
unless we feed each other.

It is that delicate... and human.

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