Cheat days

If you eat around your calorie goal on weekdays, but above your calorie goal on the weekends, it will slow loss down, for sure. How could it not? If you eat above your maintenance calories on average over the whole week (because of the extra weekend eating), you won't lose weight at all. You might even gain.

IMO, cheat days are an appealing myth, kind of like Santa Claus. Besides that, who or what would you be cheating?

You can budget your calories over the whole week, spending more on the weekend and fewer on weekdays. If you average fewer calories than you burn (in all ways), you'll lose weight.

If "cheat day" to you means just eating different food types (same calories) on the weekends, that shouldn't make any difference to fat loss at all. You might see some extra water retention after the weekend, so a bit of a scale jump, since many treat foods have extra carbs or salt that make the body retain a bit more water until they're fully metabolized. If that's the case, it isn't fat, and IMO isn't worth worrying about.

If "cheat day" to you means not logging your food . . . well, then the only way you'll know the impact is by doing it, and seeing what your scale-weight results are in 4-6 weeks. (It tends to take that long to see a reasonable average, because weight loss isn't linear.) Logging all days gives you more info about what the impact may be.

I've been at this for about a year of loss (obese to healthy weight), and roughly 8 years of maintaining a healthy weight since. When I was first losing, I logged like it was religion. Ditto for the first few months of maintenance. I wanted that data about what was going on. (I'm a data geek, one of those "you can't manage what you don't measure" people.)

Then and now, though, I ate at my calorie goal most of the time, maybe a bit under if I wasn't hungry for some reason, and over goal sometimes for special reasons . . . way, way over on rare occasions. It's what we do most of the time that will deliver most of our results, not the rare day when we eat too much birthday cake or work out for 5 hours. Those rare days are a drop in the ocean; routine daily habits are the ocean.

Two days a week, every week, though? It's easy to eat enough in two days to wipe out the whole rest of the week's calorie deficit. That could be a problem.

Your call about how to distribute your calories through the week, though.

Best wishes!