Tim's glass house
"weight is a simple function of calories ingested as against calories expended"
This is such a massive oversimplification, Tim, that I must call "bullshit".
Not all calories ingested are absorbed, and there are a large number of factors which influence exactly how many of the ingested calories turn to fat. Calories expended are but one of these factors.
You might know something about economics, but you seem to know very little about nutrition and the digestive system.
For someone that seems to make a sport out of bashing those that don't do their research properly, you might either move out of your glass house, or stop throwing stones.