I ordinarily don't eat lunch. Or breakfast. I eat a large dinner. If you eat less carbohydrates your body won't feel bad when it runs out, which might be why you feel bad after eating, if it's a while after.

Today, i'm eating lunch, and it's some pasta with olive oil, dill, and some canned tuna. Most of the time I eat the pasta right out of the fridge without heating it. You don't even need olive oil if you use tuna packed in olive oil.

Other times, I'll eat some raw vegetables and a can of some sort of meat, or I'll eat leftovers. Usually cold.

I've been intermittent fasting for quite some time, and it kind of makes you reevaluate your relationship with food. A meal can certainly be a luxurious experience, or it can just be fuel to get you through your day. I actually prefer eating one large meal a day, but it does tend to increase your cortisol levels, so when i'm already very stressed I tend to eat some lunch.