I really wish that would do it. As part of a request from a doctor, I kept a food diary for a month. I was supposed to eat like I typically do, but once you start writing things down, you tend to alter things slightly -- I tried really carefully to keep things "typical". I was always above 4,000 calories and some days I broke 7,000.

I didn't share much about my diet because it's embarrassing. The calories I consume are the worst kinds if current medical dogma is to be believed. I eat a lot of refined sugar/high-fructose corn syrup containing foods and otherwise love my carbs. By every measure, I should be overweight or otherwise unhealthy the way I eat. But the "big" health indicators (liver, pancreas and heart numbers) are all fine or exceptional and my weight is normal/below normal (140-145 lbs at 6')[0].

Here's a "typical" day for me:

Starts off with cereal or eggs, the former being more common due to convenience. Cereal is two large bowls (which I purchased because I love "kid cereal" and with four children, we always have some handy). Those bowls hold 3-4 servings depending on the cereal. Otherwise it's 6 hard-boiled eggs (and I often add in a bowl of cereal after that for "11sies"). The calorie count varies but over 500 isn't unusual. Lunch varies a lot, but a typical one for me is a whole frozen pizza, clocking in at 1,000 calories. I don't eat that every day but that represents the amount of food I'm used to consuming for lunch.
Dinner is prepared by my wife almost every night and it's quite sensible because she cares about her diet so it's usually high protein, low/medium carb (and always tasty). Those are the meals. I mentioned four kids... we have an unlimited supply of snacks and I don't regulate myself at all with this. I've been known to kill an entire bag of Reese's Penut Butter Cups at 1,990 calories (my wife hides candy from me). I've knocked one off today and if I had another, I'd be starting into it. I drink a lot of liquid but only about half of it is water, the rest is around 900 calories of a variety of juices/sodas that I love. And that chocolate milk-shake (not included in the "liquids", it's more of a snack) clocks in at 1100 calories on its own.

I'm not certain why I don't gain weight. My parents/friends will tell you that "I'm always moving" (I have a "jimmy leg") but there's no way I'm burning enough calories that way to offset all of that. I've had so many tests done in this area to rule out a variety of physical problems but they've all come out fine. And at the end of the day, it's a good problem to have (I'd like to be less skinny, but I'm old enough that I've accepted that this is the way I am).

I've also tried a variety of other diets, including high protein (which was effectively nearly no carbs), calorie restriction, fasting and other things all as personal experiments over the last decade and a half and I've failed to change my weight in any substantial way (though I felt the most healthy on the high-protein diet and I occasionally get in a kick and do that when I can afford it).

I know the data varies, but I'm a believer that genetics has a lot to do with it. My dad ate nearly this bad and -- in his 60s -- he's in the thin range as well (though his cholesterol numbers are terrible compared to mine, so I may have to adjust at some point).

[0] And I forgot to mention I actually own* an ultrasound body fat percentage device from back when I was trying to gain muscle. Back then, prior to working out, I was on the low side. I have no idea where I am today, but moving some furniture last week was about as difficult as I'm used to.