During my first few months of OMAD I would have a whopping 10-12 slices of pizza on top of other things every Sunday, within a 2-4-hour window, theoretically and conservatively putting me on a 3k kcal surplus for the day or equivalently a ~430 kcal average daily intake increase for the week. Considering that – despite throughout the remainder of the week not eating on a massive deficit nor compensating through physical activity – this still didn’t stall me out (I was losing at a fairly consistent rate of ~0.75 kg/week (1.65 lb/week) at the time), my hypothesis is that on such feast days I would either a) reach a ceiling of nutrient absorption and prematurely excrete the rest, and/or b) exhibit a disproportionate spike in TEF expenditure (usually 5-30% of intake, typically much closer to the lower bound when it comes to processed food without much protein and fiber). I’m not suggesting that you can or even should “exploit” the system, just that you might have a bit more wiggle room than you think, so long as such feasting remains temporally constrained and exceptional in nature, not threatening to destabilize your newfound routine.