Irrelevant. You can eat nothing but twinkies and still lose weight as long as you maintain a caloric deficit. Certain foods are going to make that easier and healthier, but that's orthogonal to the actual weight loss.
My point is that not all calories are equal as far as the consumer is concerned.
As others have noted, eating RDI (or just under) with only carbs - eg the twinkies diet - would be tiring and soul-destroying, likely very difficult to sustain.
Eating the same amount (calories) of proteins and fats would keep you much happier and healthier.
Eating a lot more (calories) of proteins and fats, and avoiding as many carbs as possible, and you're probably lose weight without having to track & maintain a 'caloric deficit' state.
You can but you will be hungry and it will be very difficult. You want to avoid carbs and sugar because carbs get turned into sugar and they spike your sugar levels, causing your pancreas to produce insulin to tell your body to store the excess sugar in your fat cells. Then when the excess sugar is all stored, you get the crash and you're hungry again. This is why people want to snack between meals.
Instead, avoid carbs and eat proteins and healthy fats. You won't get the sugar spike and crash, and will last hours without getting hungry. It is easy to eat only twice a day this way.
Irrelevant. You can eat nothing but twinkies and still lose weight as long as you maintain a caloric deficit. Certain foods are going to make that easier and healthier, but that's orthogonal to the actual weight loss.