Whatever you do, do not make a big issue about his eating. He will learn a lot from you depending on how you react. Just as if I refused your offer of food at your house, I'm sure you wouldn't make an issue of it. Always offer small bites of food when it is time to eat. If he doesn't eat it, don't even discuss it. Just act as if it is normal not to eat it.
When he has another growth spurt, he will be very hungry again. He will probably start trying foods again then. And don't be surprised if he likes something one day and then doesn't the next. If he continues to lose weight, then be sure to check with your pediatrician.
Be sure to never discuss his eating habits in his hearing range. Some kids learn that it is an easy way to make mom and dad very excited and they love to see their parents overreact.