I started to notice about a few months after having Covid, (I had it 5 times and it wasn't as bad as other people's stories I heard), that I was having bad GI issues when I ate. For background, I am a healthy eater. Breakfast usually included oatmeal with some fruit on top, egg whites, and some Greek yogurt, Lunch was usually leftovers from the night before, again healthy: grilled chicken and quinoa, etc... Dinner was the same- very healthy. It made no sense to me that I started to have these issues with eating. Bloating and inflammation was the worst because it prevented me to eat. I try to take in at least 2400 calories a day. I also work out 3-5 times a week. Without the extra calories, I was fatigued all the time. Other symptoms included very irregular bowel movements, (I noticed that fat wasn't being digested properly, actually showing up in my BM), achy joints, and insomnia. I went to my GP first, she was useless. She prescribed Ambien for the insomnia, but ignored the rest of the symptoms. Next I went to my gastroenterologist. He did an endoscopy, tested for Celiac's, but I tested negative. He did not suggest a Gluten Intolerance test (rolling my eyes at that...). He basically found nothing, but did notice inflammation during the Endoscopy.
It wasn't until my wife suggested that I start to remove a food group from my diet a week at a time and see if the issues persist. Luckily I started with bread/grains first. The improvement was immediate. She suggested that gluten might be an issue. I started a gluten-free diet and I've only had issues when gluten was introduced accidentally. I eventually called my Gastro and he scheduled a gluten test, which did indicate that I was intolerant.
It's hard to think that Covid had nothing to do with this. I also had some symptoms of long covid- some foods that I used to like made me nauseous by their smell, alone. That has since diminshed. But the GI still persists.