食欲 and 空腹: appetite and hunger
Distinguish the desire to eat from hunger and read contrasts between them.
The desire to eat
食欲 (しょくよく) means appetite. 「今日は食欲がありません」 says that the speaker has no appetite today.
「運動した後で食欲が湧きました」 says that appetite developed after exercise. 湧く here describes a desire arising.
Being hungry
空腹 (くうふく) refers to an empty stomach or hunger. 「空腹を感じます」 means feeling hungry.
「空腹のまま出かけました」 says that the speaker went out while still hungry. のまま marks an action performed with that state unchanged.
Contrasting the two
「空腹ですが、食欲がありません」 says the speaker is hungry but has no appetite. Related sensations do not convey identical information.
「食欲がないので、少しだけ食べました」 says the speaker ate only a little because of having no appetite. 少しだけ must not become eating nothing.
Does 「食欲がないので、少しだけ食べました」 mean skipping the meal entirely?
Show the answer and why
No. The speaker ate, though only a small amount. Distinguish the lack of appetite from the amount actually eaten.