An objective look at eating "exercise calories"

One issue that seems to be related to MFP more than any other forum I post on is the question of "to eat or not to eat" the calories one expends exercising. I'm assuming it has something to do with the logging and calculations used on MFP, which I am admittedly unfamiliar with. However, suffice it to say that I get this question in my inbox a few times each week, so it's obviously worth mentioning on the forum.

First, let it be known that there are no universally accepted rules regarding eating them back or not. The reason being is because there's no magic to it - it comes down to energy balance. Nothing more. Let me explain...

Let's try to make this real simple:

Maintenance calorie intake is where calories in = calories out, right?

We know that a calorie deficit is required if fat is to be lost, so calories in < calories out.

Large deficits can have negative effects such as increased cravings, muscle loss, irritability, unsustainability (I made that word up), etc.

So we want a moderate deficit, which I'd label as 20-35% off of your maintenance. There's latitude here, mind you.

So if your maintenance is 2000 calories, anywhere from 1300 to 1600 calories would be realistic for fat loss.

That's a deficit of 400-700 calories per day.

Said deficit, in theory, could come from a number of combinations.

On one end of the spectrum you could simply eat 400-700 calories less per day. This assumes the energy out side of the equation stays reasonably static.

On the other end of the spectrum you could keep eating 2000 calories but increase calories expended via exercise to 400-700 calories per day.

If you went with this latter scenario, you wouldn't have to eat back your exercise calories because the expended calories from exercise put you in the sweet spot, calorically speaking.

Now if you cut calories by 400-700 AND increased activity by 400-700, then you'd be running too large a deficit unless you ate back your exercise calories. I can't express how general this is, but it's something many should listen to. Obese folks, on the contrary, can run much larger deficits than thinner folks for reasons we won't get into here today. But all of these relatively thin folks who are trying to "beat their bodies into submission" by blitzing it full force with calorie deprivation and massive amounts of exercise should probably heed this advice.

In real terms, most people establish their deficits partly by cutting calories and partly by increasing activity. But for those of you wondering whether you should be eating back your calories expended exercising, you need to look at your calories in net terms. Where does your deficit stand without eating back your exercise calories?

I'll note that personally I don't worry about any of this with my own training or my clients. I set what I consider sane and productive volumes of various exercise (strength training, energy system development, conditioning for fat loss, etc.). From there, there's really not a lot of variability in energy expenditure since I know, by and large, what volume of exercise is required to drive the adaptations I'm shooting for.

Therefore, the only thing to really manipulate is calorie intake. It's a much cleaner approach but to each his own. Do what you're happy with and what makes the most sense for you.