I feel light headed and tired after i eat something.

See primary: Soemetimes we can get tired after eating a large meal but the lightheadedness should not happen.Go and see a physician and get tested for diabetes and get a physical.Everything may be fine but should not take a chance.

Food sensitivity or:: This suggests food sensitivities- often caused by common foods such as gluten,dairy,eggs,corn or soy. It's often due to parasites,overgrowth of yeast or unfriendly bacteria in the GI tract. Try a Pegan-type diet avoiding those foods for 2 weeks then add back one at a time: see http://tinyurl.com/yb9guouj If not better after that see integrative Dr. If gut is really leaky might react to any food!