This must depend highly on where your calories come from, because for most people it really isn't that easy. Even bodybuilders will switch to liquid diets to try to pack that much away. If you're consuming lean protein, fibrous vegetables, nuts and pulses, 4000 calories in a sitting is far more difficult. Think of how many apples you can eat in a sitting, and consider that a single apple is 52 calories.

Caloric density is not discussed enough

The only significant contributors to calories and mass of any food item are water, proteins, carbs, and fat. They are respectively 0, 4, 4, and 9 calories per gram. So, foods that are waterlogged (fruits and veggies) are very low calories per gram and foods that are fattier will be denser.

Honestly curious: Is there more discussion to be had than that?

Just understanding how fullness relates to calories. How a full meal of something that is less calorically dense can divide your calorie intake by two compared to super fatty processed foods.

For me, I don't need to exercise restraint during those 8 hours. I sate myself. It's still an overall caloric reduction, for me at least.

>Packing away 4k calories in a single meal is trivially easy

Does it take must restraint to just eat like 2K calories in a 8-hour span?

Never had much problem with that during IF, and I used to have a BMI of over 35, so I was quite the eater...

I used to weight twice what I do today, so I know a thing or two about eating too many calories, and I lost that weight so I know a thing or two about not eating that many calories.

Thing is, a rule like "only eat in an eight hour window" leaves plenty of time to consume huge amounts of calories. I've been known to pack away 4k+ in a meal, both in the past and today. It's not even hard for me. In fact, it's rather hard not to once I start eating because like many people who are of have been fat I'm a food addict.

Some here are saying things like "well, good luck eating 4k of lettuce dude!" and yeah, that is hard. But if you're eating lettuce and vegetables and all that low calorie stuff already you probably don't need the 8 hour window restriction!.