"fainting after meals"

Near Fainting After Meals? Dumping Syndrome, the Post-Meal Misery Caused by Overeating

A good meal should leave you feeling satisfied, but does your head spin and do cold sweats break out instead? Have you ever felt bloated, completely drained, and so dizzy that you wanted to collapse onto the floor? This could be the start of the post-meal distress brought on by overeating.