This morning I weighed 164.6. So in 4 days of averaging less than 2000 total calories and more than 12000 steps per day, the scale went up 4 pounds. I know it's a spike and mostly water and more food in the gut, but still annoying.

@Tucson - In previous yoyo diets, I lost way too quickly. In 2014, I lost close to 60 pounds in about 6 months. A couple of years ago, I lost about 25 in around 2 months. I did not know about adaptive thermogenesis then. I would just do crazy crash diets without tracking calories or macros. A lot of times I would skip breakfast or just have a banana, have a packet of tuna with hot sauce stuffed in a bell pepper for lunch, no snacks and then small portions of a normal dinner; probably in the range of 800 to 1000 calories a day. That's one reason I know that starvation mode is a myth; the weight just melted away when I did that. But it probably did drag down my metabolic rate. I don't know if you read one of the things about muscle loss, but it seems like the body is smart about that and you lose more "fast twitch" muscle which burns more calories.