I have a question. I've always wondered if you have a day or two where all you eat is sweets but only have around 1000 calories or fewer total, will you still lose weight for that day?
I want to make it clear that I'm not thinking about doing this and in no way do I condone this kind of eating. I have a very healthy diet, but I was just curious.
The biggest problem with that plan isn't the eating-nothing-but-sweets part but the under-1000-calories part. Eating so few calories on a regular basis is incredibly bad for you and slows your metabolism down to a crawl. Of course, the lack of nutrients would be bad too. Far better would be to have a day where you ate sweets *and* healthy food. Eating the same number of calories as you burn every so often is very good to keep your metabolism from slowing down. The calories in sweets aren't inherently more fattening than the calories in anything else; they just don't have much nutritional value.

