Exercise calories - can someone explain?

[HappyAzure]

So I’m aiming for 1200 calories a day (when not on a ‘2’ day of 5:2). I’m doing regular runs/spin classes which usually burn about 250-300 calories according to my Fitbit. Does this mean on those days I need to eat 1500?? Or still 1200 but then overall surely it’s only 900? I don’t want to be in a constant fast.

Do you take notice of exercise calories? I know they aren’t super accurate anyway.

Ideally with 5:2 you shouldn't use a fitbit or other exercise tracker and 'eat back' your exercise calories, because you usually work off TDEE and try and keep your NFD calories fairly consistent, rather than fluctuating depending on how much exercise you've done on a particular day (do understand though that it's quite motivating to get to eat a bit more if you've exercised). Have to say that as you sound at least lightly active, 1200 sounds very low for a NFD even if you don't do any exercise, never mind 900!

Obviously I don't know your exact details but as a guide, using tdeecalculator.net/ , if you were 40, 5ft 6 and 10stone, you should eat 1500 calories on a NFD if you are sedentary (no exercise), 1800 if you are lightly active or 2000 if you are moderately active. If your fitbit is estimating 250-300 calories burnt and you exercise most days I'd say you are lightly active...

Where did you get 1200 from, are you really small/short? Are you trying to 'save' some calories for the weekend? Remember that on 5:2 your calorie deficit comes from the fast days so you can eat much more on the non fast days than you will be used to on typical calorie counting diets...

@maxelly

Ideally with 5:2 you shouldn't use a fitbit or other exercise tracker and 'eat back' your exercise calories, because you usually work off TDEE and try and keep your NFD calories fairly consistent, rather than fluctuating depending on how much exercise you've done on a particular day (do understand though that it's quite motivating to get to eat a bit more if you've exercised). Have to say that as you sound at least lightly active, 1200 sounds very low for a NFD even if you don't do any exercise, never mind 900!

Obviously I don't know your exact details but as a guide, using tdeecalculator.net/ , if you were 40, 5ft 6 and 10stone, you should eat 1500 calories on a NFD if you are sedentary (no exercise), 1800 if you are lightly active or 2000 if you are moderately active. If your fitbit is estimating 250-300 calories burnt and you exercise most days I'd say you are lightly active...

Where did you get 1200 from, are you really small/short? Are you trying to 'save' some calories for the weekend? Remember that on 5:2 your calorie deficit comes from the fast days so you can eat much more on the non fast days than you will be used to on typical calorie counting diets...

I didn’t realise that I could eat basically ‘normally’ on non fast days - I presumed i should be eating in a deficit anyway but just more than fast day! Thank you.

1200 a day is what MyFitnessPal suggested as I want to lose about 7kgs over the next couple of months.

I know people swear by 5:2 but ultimately you just need to be in a calorie deficit overall. 5:2 is just one way of achieving that but if you eat a fuck load on your 5 days it isn't going to work as your calories in will be more than your calories out.

Fitbits aren't accurate I'm afraid so please don't trust it to give you an accurate reading of how many calories you're burning. Most trackers over estimate. It's a good gauge to compare between workouts but I wouldn't trust it to inform what you eat. For that, you can use a good online tool like IIFYM - put your lifestyle in as sedentary (most people are - this does not account for exercise).

Honestly, unless you're going to say you're under 5 ft and weigh 8 stone 500 calories on 2 days and 1200 on others is so so low. I'm 5'3, 9'7 stone, exercise 4-5 times a week and eat 1500 to maintain that.

Just remember - weight loss is all about eating less than you burn BUT your tracker won't be accurate so don't rely on it!

Just to be clear (because I don't think I was) a Fitbit isn't useless - it's really good for comparing the intensity of one workout compared to another. And it'll track your steps.

Also MFP is really aggressive on calorie deficit and isn't sustainable for most people.

Anyway, I applaud you for taking your health and your weight seriously. It took me a long time to get to a point where I had any motivation so I really admire those that do in a climate where there's so many temptations to be lazy and eat lots of sugary treats!

When I did noon for a. It it seemed to add half the exercise calories back as food intake. So if you burnt 300 it would allow 150 cals extra food

@chestnutshell

I know people swear by 5:2 but ultimately you just need to be in a calorie deficit overall. 5:2 is just one way of achieving that but if you eat a fuck load on your 5 days it isn't going to work as your calories in will be more than your calories out.

Fitbits aren't accurate I'm afraid so please don't trust it to give you an accurate reading of how many calories you're burning. Most trackers over estimate. It's a good gauge to compare between workouts but I wouldn't trust it to inform what you eat. For that, you can use a good online tool like IIFYM - put your lifestyle in as sedentary (most people are - this does not account for exercise).

Honestly, unless you're going to say you're under 5 ft and weigh 8 stone 500 calories on 2 days and 1200 on others is so so low. I'm 5'3, 9'7 stone, exercise 4-5 times a week and eat 1500 to maintain that.

Just remember - weight loss is all about eating less than you burn BUT your tracker won't be accurate so don't rely on it!

This is actually really helpful. Thank you. I don’t follow my FitBit to the letter and I plan to just generally eat a bit less/lower carb on ‘normal’ days so I won’t be eating loads of rubbish anyway.

I’m about 5’6 and currently about 9 stone 5 so normal weight really but I look better and feel better when more around the 8.5 stone mark.

@HerRoyalNotness

When I did noon for a. It it seemed to add half the exercise calories back as food intake. So if you burnt 300 it would allow 150 cals extra food

Interesting - thank you!

Aha, yes you can use MFP to track your calories on 5:2 if you want but ignore what it tells you to eat on a daily basis and only ever review on a weekly or monthly average - if you are monitoring day to day you'll find it nags you for not eating enough on fast days and then tells you off for eating too much on NFDs, clearly not a 5:2 convert .

As a minimum on 5:2 really you should be eating to your TDEE for sedentary on your non fast days - anything much less and you will be really hungry and may start feeling faint/nauseous! Some people do save a few extra cals for the weekend by eating a little under on their weekday non fast days but this is a bit advanced really - I'd start by sticking strictly to 500 on fast days and to your 'true' TDEE on NFDs (I'd set it to lightly active based on what you've said in your OP).

Monitor how you do with weight loss on this for 6-8 weeks, if you find you aren't losing weight then you can try reducing the NFDs slightly but as I say the calorie deficit on 5:2 should only come from the fast days, not the 5 'normal' days (although if you are a long term overeater it may take some adjustment getting used to what 'normal' looks like)!