How do you do treat meals? I usually treat myself to eating out once a week, usually on Saturday night. I order whatever I want off the menu, and also have whatever dessert I've been craving. Then, back to healthy eating in the morning! I find that this helps me stay on track throughout the week.
*No foods are "off-limits" for me, but I have a hard time having tiny portions of indulgences throughout the week. I just eat the portion I want on Saturday, and leave it at that.