Here's how your body works - it WANTS to work optimally - so if you are living an optimal lifestyle - you are feeding (or fueling) it as soon as it has completed burning (metabolizing) fuel from the last refueling. Generally carbs metabolize pretty quickly, like an hour, proteins a little longer, fats, the longest, but all within 2-3 hours. Thus you get the idea of eating smaller meals every 2-3 hours -- providing a refueling as your body finishes burning what it had before.
Also following a clean diet, you are providing clean fuel in whatever ratios you choose of proteins / fats / cabs. You can feed your body what it needs over the course of the day to match the types of activities you will be doing. Protein at every meal. Carbs in the morning because you need to kick start your day and also break the "fast" of the last 8 hrs of sleep during which you haven't eaten anything. You would also want to put other carbs over the course of the day when you are most active, usualy not later in the day or at night because all you are going to do is sit / sleep. You don't need the immediate energy that carbs give you. That said, immediately after a training session your body has depleted the glycogen it had available as energy for the training, and now if you give it some more simple carb, it will suck it up immediately. Fats will help slow down metabolism of the meal -- if you have a stretch of time during the day when you can't get to your next meal right on schedule, you can throw a fat into the previous meal & you can slow the digestion process down so you aren't starving while you are waiting the extra long period to get to the next meal. Same for putting a fat in your last meal of the day so you won't wake up in the middle of the night starving.
OK. So now you've been eating this awesomely clean diet all week. Possibly a restricted lower carb diet. If you follow this restricted diet for an extended period of time, a couple things happen. First you start to hate the diet because you feel like your lifestyle is being restricted by it. You get sick of the same food. You start getting chocolate cravings
, whatever. And also, that restricted diet may have some consequences such as, lack of enzymes from no fruit, to help clean out the various free-radicals and other 'debris' that need to be shuttled out of your body. You may be running low carbs for extended periods of time -- your brain runs on carbs so when you are extremely low on carbs, you start feelign foggy & "stupid" in the brain. You also get tired (no carbs to feed your energy needs) and you start to look flat. And finally, when your body adapts to a very restricted diet, when it does get something in it that is higher carb or just some junk, it isn't really equipped to handle digesting it. For example, while prepping for a bodybuilding show, I cut out all dairy for nearly 3 months. One night I figured one spoonful of ice cream would be ok. I blew up from gas SO FAST it wasn't even funny. (Sorry for the detail.) But I had zero lactose tolerance at that point.
So, the idea of a cheat meal is:
- Give your body a one-time feeding of a lot of the stuff it has had restricted from it.
- Give you a break so you can accommodate your social life, your cravings, whatever.
How much should you have -- depends on your goals again. If you are prepping for a show - well, you dont' really get any cheat meals after about 5 weeks out from the show. If you are just happily making progress, you can cheat for the day. If you are tight on your diet, just do a single meal. Or cheat for a set period of hours on a day and then stop after the time is elapsed. How much do you cheat - again remember that if you gorge yourself you are going to pay because you still have to metabolize all the shit you just ate. You may also feel like crap if you toss back a bag of cookies when you haven't eaten any refined sugar for a while - you might get a massive sugar buzz, headaches, etc.
I would suggest scheduling a cheat meal where you eat "normal" -- nice dinner, dessert, glass of wine - whatever. Dont' turn it into a feeding frenzy. And frankly, after you eat clean for a while, you really start wanting to continue to eat clean. But it gives you a chance to relax for a little.