GP is talking colloquially, they're talking about "large calories" (food calories, Calorie, …) aka 5000kcal. FDA recommendations is 2600kcal RDI for a healthy lightly active adult male.

The "extra energy needs" is 2400kcal, olive oil is 884kcal/100g, that's 270g of olive oil, about 300ml.

That's pounding down half a standard bottle every day, and at least a buck or two. Aside from getting cheap as hell olive oils, you seem to use ladles for spoons.