I think in the reference to this thread regarding cheat meals it is referring the a diet much more strict than is done normally, to achieve a short term goal. Assuming that is correct, its common for caloric intake to be significantly lower than normal. But doing so can be hard work physically and mentally. Allowing yourself a cheat meal every so often goes a long way to easing the mental fatigue hard dieting brings without affecting the overall plan.
For me, it's a mostly useless practice unless you make a living from being in a certain condition for a specific period of time or to compete. Not only is it a unhealthy practice long term, it can also lead to excessive weight gain afterwards. There are only a select few who have the discipline to diet hard all the time, but many hear would admit to it being unsustainable for more than 2-3 months.
For me, I find it far more sustainable to just practice eating clean healthy foods regularly and having the occasional treat in moderation. Its easy to make small changes to food intake and exercise to adjust body fat %. While the changes happen more slowly, the results are more sustainable long term.