Your metabolism works on a CONSTANT basis, not a "one hour basis". Since we usually think of our own lives in terms of days, we tend to calulate caloric intake based on a 24 hour period. That doesn't have anything to do with how your body uses food as a whole (discounting hormonal changes and time periods related to before and after training). With that in mind, that post from eons ago was related to how your body uses food. If you calculate your daily maintenance caloric intake to be 3,000cals a day...and you only eat 2,800cals a day even at only one meal a day, you will not gain weight. Because over the course of a week, you have still taken in less food than your body needs to maintain your weight.
The main point of that post was to inform someone that eating a large meal does not mean you immediately gain body fat. Your body isn't that spontaneous in how it reacts to food intake. No one goes to Pizza Hut for a buffet ONE DAY and suddenly gains 10lbs of body fat. If they go every day and always eat more than it takes for their body to maintain their body weight, they will gain weight. How much is fat, muscle or water is based on many factors from genetics, to metabolism, age, sex, body size, and activity levels.