I had some of that too though, that's kinda the idea. I found carby foods were most consistently weight adding, while meaty and fatty not so much.

I recall all you can eat bbqs actually resulting in weight loss the following day. But if I had a bowl of rice with them, I'd have the weight gain I feared. Moderate portions of Indian takeaway curries with Naan could keep my weight up for a few days.

That's not something I'd expect from pure calorie counting, nor do I understand what's actually going on or if it's good or bad etc. But it seemed useful to be aware of