Eating back exercise calories - an attempted answer of why do it!

Caz

Repeat Offender
WARNING: This will be an epically long post so sorry! Hopefully it'll be useful though!

The question about whether you should eat back your exercise calories seems to be an age old question that no-one seems to really understand. I hear lots of people saying so then what's the point of exercising? So I'm hoping that I'll be able to explain why eating them back benefits you and hopefully this will help someone. I'm not saying you HAVE to eat them back, it's a personal choice and whether you do or not is up to you, I just personally agree with it and have far better losses if I do.

I get the logic of well if I don't eat my exercise calories back, I'll have better losses and get to goal quicker. It's one I had and it's kind of right but kind of not too.

I've explained it to people like a car journey before. Basically, if you're about to do a journey in a car and you know that it's a 1600 mile trip, therefore taking 1600 miles worth of fuel and so you fill up that amount, you wouldn't then expect to be able to do a detour adding an extra 400 miles without putting in more fuel would you? It's not different with your body, like a car it needs fuel for all of it's daily functions like growing your hair and nails, skin replenishment, organ function, breathing etc. For most people, that takes between 1200 and 1800 calories a day, that's what you'll burn every day, regardless of your activity and that's why people say not to eat less than 1200. But that's a NET of 1200, after exercise, otherwise you've increased your body's daily burn but not given it enough to do all of that.

That's what you burn each day, regardless of what you do. So lie in bed all day and you'll still burn that, it's called your Basal Metabolic Rate (BMR) and you can calculate it here - BMR Calculator

You can then use your BMR to calculate your Total Daily Energy Expenditure (TDEE) which is what you burn each day based upon how active you are. You can calculate it here - TDEE Calculator For every 500 calories you go below that each day, you'll lose 1lb a week. 500 x 7 = 3500, there are 3500 calories in 1lb of fat.

If you use My Fitness Pal then it does these calculations for you so you can eat what it recommends, plus your exercise calories. So, let's use me as an example.

I currently weigh 240lbs (urgh, I know :(), I'm 5ft 9in and a 25 year old female. That gives me a BMR of 1,905 calories. So no matter what I do, I'll burn 1,905 calories a day. Then, I would say that I'm lightly active as I'm at uni and a teacher so I walk around and am on my feet quite a lot, so that makes my TDEE 2,613 calories. That means that I need to eat 2,633 calorie per day to maintain my current weight. So if I eat 1,633 a day, I should lost, on average 2lbs a week and I shouldn't really go much below that number because it's recommended that you don't cut by more than 1,000 a day.

Ok so that bit gives you how much you should eat, now here's why you should eat exercise calories.

So, let's use me as an example again. We'll say that I currently weigh 240lbs (which I do) and want to lose 60lbs to reach 190lbs (which again, I do!). I have a BMR/metabolism of 1900 a day and with a sedentary lifestyle, I'd burn 2400 a day. I want to lose 1lb a week and so I cut my calories down to 1900 a day to do that, because that's what MFP has calculated for me and it's what the websites above suggest too. But I've decided I want to get fit as well and so I start exercising and then I burn an extra 500 calories a day at the gym, which gives me a NET calorie intake of 1200 calories a day, NET being calories I've eaten - calories burned through exercise. So, that extra exercise now means that my body has only 1200 calories to function on, even though I know it needs 1900 and I should lose around 2lbs a week because of the extra burn.

So what happens then? Well, I'll still be losing weight but along with fat, I'll also be losing muscle, which obviously isn't a good thing. This is why sometimes we see decent losses on the scales but we're not really getting any smaller - what you're losing is muscle not fat. So then my body has to adjust to it's new intake and my metabolism drops to meet what it is that I'm giving it to function with each day, this is again NET, not just what I consume. So using the example of me, my metabolism drops from 1900 down to 1200. So I go on and lose my 60lbs and reach my goal weight of 190lbs. That's great right? Well it is but now I have to maintain. Problem is, my metabolism has dropped to 1200, which means that I can only eat 1440 a day without gaining weight (1200 x 1.2 - the activity factor for sedentary).

Obviously, the option to reach goal and only be able to eat 1440 calories a day SUCKS and isn't really sustainable. So, what can I do about it? Well here's the other option. I can eat back those 500 exercise calories a day and still lose the 1lb that I've aimed for because my NET calories are still 1900. My metabolism should, with this option, actually increase because I'm exercising and building/preserving muscle, which increases your metabolism and because I'm eating enough for my body not to lower my metabolism as a survival mechanism. So, I reach my goal of 190lbs and my metabolism isn't still 1900 because I now weigh less, but should be close to 1700, meaning I need 2040 to maintain.

So by eating back my exercise calories, I'm meeting the calorie need that MFP and websites say that I need and I'm not damaging my body or lowering my metabolism, whilst still losing weight. Beyond helping your metabolism, the exercise has loads of other benefits but I won't list them and make this post even longer but you'll look far better at the end, toned rather than skinny fat! Hoping this helps clear up a few questions that people have, if you've made it this far! I've done quite a lot of reading on this so if anyone wants to know some of the websites I've looked at, just let me know.

And if you have made it this far... I'm impressed!
 
Very interesting post :)
 
Yeah I missed out that point, gives you more calories for yummy food!
 
When eating back excercise cals how do you know exactly how many cals youve burnt from the excercise? Also... whats the point in doing the excercise if it doesnt actually help your weight loss... it seems that you're saying once you excercise you should eat them back and be back up to the same amount of cals. Isnt that the same as just staying on say, 1900 cals and not excercising at all, as opposed to being on 1900, excercising for 500 and eating them back?
 
The exercise will help tone your body, also a body with more muscle actually burns more calories I think (e.g if me and my OH walk the same distance he gets more benefit as he's more muscular)

In theory you could maintain the same weight but lose inches through muscle gain. I also think you're going to get better results all round if you do exercise.
 
The exercise is for fat loss and toning - i personally eat 1200 cals and eat back most of those cals I burnt - I think as long as your net is 1200 you are on the right track:) x

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Well I posted about this a while ago so I'll just copy and paste!

So then there's the question of, if I'm working my ass off to burn 500 calories a day and then eating those calories back, then what's the point I might as well eat less and not exercise. WRONG! Exercise has a lot more benefits than just helping your weight loss. Just a few of those being:

- You're creating a healthy and active lifestyle that will continue once you've reached goal and are no longer counting calories to 1200
- It allows you to eat a little more and therefore makes keeping to 1200 calories NET easier
- It means that you can work off the higher calorie meals that you have when you go out or have a special occasion
- Boosts energy levels and helps you sleep better
- It builds muscle and tones changing your body shape
- Strengthens your bones
- Regular exercise makes you less likely to suffer from certain diseases such as heart disease and diabetes
- It improves your overall fitness
- Exercise releases endorphins and improves your mood
- Reduces stress levels
- Lowers your heart rate and blood pressure through improved circulation
- Increases chances of living longer
- improves posture
- Enhances your immune system so less likely to get ill

I could go on, but I think there's enough reasons there!
 
Both of your posts are correct and made a lot of sense.
 
Great thread!! Thanks!!
 
I love this tread. X
 
I'd like to add that exercise helps reduce bloating which makes you look slimmer.

And I also have alot of stomach complaints and the gym really helps manage the pain, probably something to do with endorphines as mentioned by caroline :)
 
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