My son: Part 1

My son doesn't eat. He's never been much of an eater, except for when he was a baby, drinking formula, and then he just drank the normal amount. I wouldn't necessarily call him a "picky" eater. He just doesn't eat anything at all, and I think of picky eaters only liking to eat certain things. He does like sweets, though. But, he will beg and beg for a cookie and after I convince him to eat 3 bites of his dinner (that's 3 bites total, not 3 more bites) he will take one bite of the cookie and be finished with it. He has gone through phases where he has eaten a lot, but those are usually short lived and don't amount to much in the weight gaining department. He's always hovered anywhere in the 3rd-7th percentile for weight. The doctor tells me that if he drops below the 3rd percentile, we will need to look into causes. But these past couple of weeks, his eating has gone from small amounts to minimal and almost none, some days. He regularly sits at the dinner table for about 45 minutes without eating a single bite, then goes to bed without eating, and doesn't seem bothered by it in the slightest. Every once in a while he will wake up in the middle of the night, or just a couple hours later and say that he's hungry. I'll bring him some bread (sometimes with peanut butter on it) and he'll eat 2-3 bites and then give it back and go to sleep. I just recently started doing this because I'm actually concerned about how little he eats. I used to tell him "too bad, you'll eat at breakfast". But still, it's not like he's eating a lot when I bring him something at night anyway. He has plenty of energy during the day, and certainly drinks more than enough whole milk, (I mean, he really drinks a lot of it) so maybe it's fine. And, in all honesty, I don't require much food either. I rarely finish a meal when we are out. (I rarely finish half of my meal when we are out, unless it's so delicious it's worth having a stomach ache afterward from being so full) Although I enjoy food, I'm perfectly happy eating several small meals throughout the day. And I don't equate a full stomach to being satisfied with my meal, or with life in general. So, maybe he is just like his Mama, and only eats when he feels like he needs to, and not because the clock says so?