While this is true, it is not particularly enlightening. The problem is that earlier a definite assertion was made that obese people burn fewer calories per day when staying at the same weight, and colomon was saying that this is known to be contradicted by certain experimental facts. It is known from experiment that basal metabolic rates are larger as your weight goes up.

It's even consistent with a simple causal model. Obese people have larger bodies, which require more maintenance -- a larger supply of blood vessels and a heart working harder to fill them, more energy expended in getting up and going to the bathroom, et cetera. So it's kind of "no mystery."

Now, it might still be the case that this documentary was correct -- for example, while basal rates might be higher for obese people, perhaps normal-weight people simply have an exercise routine which increases their metabolism in general. Something like that would be useful and would help colomon understand why the result is backwards. Unfortunately, I didn't see the documentary and therefore I don't know this particular reason, but the question is legitimate and is not well-dismissed simply by saying, "oh you know that crazy internet."

So the Hans Benedict formula (which has been in use since 1919) is directly weight related.

The Katch-McArdle and Cunningham try to be more specific and relate to the Lean Body Mass (LBM).

However -- since LBM is reasonably correlated with overall weight -- then we can assume that (all else being equal) the fatter person has a higher BMR.