You can eat spicy food after fitness.
Yes, but you'd better not eat it. Protein powder mainly comes from the food we eat. And spicy food causes intestinal problems, which will cause waste in protein. Especially protein powder with high content in protein (such as QNT whey protein powder from the United States, Saif magic whey protein powder, up to 75% in protein) will cause waste. So it's best not to eat.