Hmmm...my one cheat day so far was Thanksgiving, and it wasn't even a "real" cheat day. I ate a lot more carbs than usual, but they were not junk: sweet potatoes and some pumpkin pie sweetened with a small amt of honey.
I felt like crap for a few days afterward, so no, I'm not tempted to do it again. But I'm satisfied with my body fat percentage (~20%, I'm female) and having no trouble maintaining it. So I can't see a good reason to mess with what's working unless it'll make a big difference to gain of lean mass.
But reading about leptin is making me pay more attention to carb intake on a daily basis. Even though I'm not struggling with weight loss, I feel my lack of knowledge of leptin is a big gap in my understanding of human metabolism. Must work on that.
I'm not sure I'm understanding your thoughts on junk food vs healthier carbs and insulin/leptin. It seems as though you're saying there's a significant difference between the metabolic effects of the macros in a candy bar and the macros in a sweet potato with butter. Am I misunderstanding?
My glucose meter tells me that a sweet potato loaded with butter makes my blood sugar shoot up fast, and then decline over a few hours, presumably under the influence of an insulin spike.
If you don't mind posting a quick explanation of how a Babe Ruth and a butter-loaded sweet potato with equivalent carb/fat grams affect insulin/leptin differently, I'd love to hear it.