Huge calorie deficit, unintentional...
I'm curious to know what it takes to make your metabolism slow down in regards to a calorie deficit. Just one day of a large deficit? A week? I'm not usually a calorie counter, but I thought I'd give it a try last night, and I went back and counted up everything I'd eaten that day. It wasn't hard, because most of my foods come out of cans or single serving packages. Anyway, I had consumed only 1420 calories (not starving myself, just not paying attention to what I'm eating). I had also gone on a ride where I maintained about 14.5 mph for nearly 60 minutes. I'm a big guy, and most online calculators I've found indicate that I need anywhere from 2300-2500 calories to sustain my weight, based on an inactive lifestyle.
I didn't intend to go so far in the hole (I'm not really "watching" what I eat), and I'm going to make an effort to take in more calories throughout the day from now on. Chances are, I've had other days like this.
My main question: How could I know if my metabolism is slowing down to account for the low calorie intake? Do I just watch the scale and see if it stops moving for a week or two? And if it is, how do I get it back to normal? I've lost a little over 20 pounds in the last 3 months (compliments of cycling and a near-absence of beer), and I don't want to stop there.