I've had the exact opposite experience. Days I felt like I did well on and had, if counted, a lot less calories were upticks, and days where I indulged were downticks. Sometimes very large ones too. Particularly very fatty meals would see me drop weight.

Ultimately the treatment for what probably got me to gain so much weight helped me twice over: ADHD medication. Not only does not lessen your constant need for dopamine (and lots of bad foods are good dopamine bumps), but it also supresses your appetite. I of course wouldn't recommend it if you do not have ADHD, but the additional side effect is appreciated none the less.

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

On a day-to-day basis, weight measurement changes are dominated by changes in retained water. This will certainly correlate with daily food choices, but does not really reflect meaningful changes in body composition. Average your measurements over something like a week in order to gauge actual progress.

Carbs increase insulin more than fat or protein. Insulin is a fat storage hormone, so having carbs with your meals means you’re likely going to store more of the calories you consumed as fat.

Weighing daily and seeing the trend was what worked for me, and encouraged me to stick to my fairly brutal diet. Went from 250 to 180lbs over five months or so - and that was 15 years ago, and have maintained myself at ~180lbs, as seeing the hard evidence that “don’t stick it in your gob, you don’t need it” works has allowed me to continue on that principle.

Before the scale, I’d always bemoan that it was impossible for me to lose weight, that it was genetic, that it wasn’t under my control. More than anything, it made me realise that it was entirely in my control, and that my excuses were bullshit borne of not being able to perceive the outcomes of my previous, short-lived efforts.