Why would a guy say i need to work up an appetite?

lol lol lol! theres this guy @ wrk i think likes me, he always used to come up to my dept to chat, he asked 4 my email addy, my number and asked me to lunch. Ive started to like him back. recently i have had a lot on my mind, and have kinda lost my appetite, so i said to him 'i hardly esat now, ive lost my appetite! he replied 'u need to work up an appetite!', is he saying this in a flirty way; or is he being serious (hes pretty health conscious! haha hes a little cutie!! xxxx