[Xophmeister]

Expending resources (i.e., money) for food doesn't cause the food to immediately lose its value. Expending resources (i.e., physical energy) for eating the food also doesn't cause the food to lose its value, as it almost certainly provides more energy and nutrition than is expended in its digestion, thus maintaining the consumer (i.e., a net gain); it may also have additional value, which probably attracted an additional cost to begin with (e.g., superior flavour, scarcity, etc.)

It's an overloaded term, sure, but it's clear that consumables -- i.e., things that need to be consumed to release their value, such as food -- only fall under the category of "consumption" when there's a surplus of value that becomes illiquid. For example, eating a balanced meal when you're hungry is a net gain, while eating 50 pizzas when you don't need to isn't!