Fairly new to calories... help with calculating deficit pls

[hornchurchmum]

Hi all, I've been counting calories for about 6 weeks and using the fit bit app and food tracker and have lost 16lbs so far.

So, I found it really hard initially with lots of conflicting info about how many calories to allow myself. I am almost 6ft tall and currently very heavy. My first goal is to lose 3 stone but ideally 5-6 in total.

When I started I calculated my BMR to be approx 2020 cals per day. According to my fit bit tracker I actually burn on average 3300-3500 per day just by going to work and doing chores etc.

I've read that a deficit of 500 cals should result in weight loss. I took this to mean my actual cals burned, say 3300, minus 500, which would leave 2800! There is no way I would lose eating that much.

Then I found some info saying that people with a lot to lose could have a maximum deficit of 1500, so armed with that knowledge I've been allowing myself 1800 (3300 - 1500) and the weight seems to be coming off well. This calculation is actual cals burned, minus 1500.

This is all so new to me as I've previously done WW or SW but just can't justify the cost and the moment, and calories on foods are sooo much easier to find and work out.

Anyway... today I've stumbled across something else called TDEE which I understand to be my maintenance calories. I've calculated this to be around 2430.

So my question is... when people talk about having a 500 calorie deficit to lose weight, are they taking about:

a - your BMR minus 500
b - your actually calories burned minus 500
or
c - your TDEE minus 500?

I know I've made my own deficit bigger, I'm just using the recommend -500 to ask the question.

I just can't seem to find a straight answer and I don't want to be wasting my time.

Going by those calculations and my chosen deficit of -1500 I should either be on (a) 520, (b) 1800 or (c) 930?! There is such a huge difference between the 3 options.

Im guessing the most likely scenario should be TDEE minus 500 for most people, but I didn't even know what TDEE was until today :( with that calculation is should be on around 1930 whihx isn't dissimilar to the 1800 I've been working with.

Please help out a newbie before my brain explodes! :) I just would like one definite answer as to what the calculation should be 🙏🏼

Thanks if you got this far lol

Sounds like you are doing amazing!

This doesnt really matter because what you are doing is working but my understanding is that you should reduce your TDEE to lose weight in a sustainable way. Your BMR is part of your TDEE, the bit that you can't control and basically the minimum that you need if you were resting 24/7.

Another part of your TDEE and the part that you can control is exercise, so theoretically you could up your exercise in order to up your calories but this can be a risky strategy given that we tend to overestimate the amount of cals that we burn through exercise and we tend to under estimate the cals we eat.

Thank you 🙏🏼 I'm obvs doing something right but I just need the calculations for my own sanity 😅 to confuse it even more i'm now pretty sure that TDEE is the same as actual cals burnt, and if that's the case then my calculation is way out compared to what I actually burn according to my fit bit - but I'm also not always sure how accurate that is either! Going forward I think I'll stick with my average TDEE (but the one according to Fitbit) and stick with the -1500. Going forward I think this should naturally lower itself as I lose weight 🤞🏼

TDEE - 500 is the thing to aim for and you’re right that the FitBit estimates of calories burnt are wildly inaccurate so best to ignore that.

Also, be aware that with a deficit of 1500 calories, some of the weight loss will be because you’re losing muscle rather than fat. The greater the deficit, the greater the risk of muscle loss, which in turn will have an impact on how many calories you burn on a daily basis.

Ok thank you. Who knew calories were such a minefield! So you think even though I wear my Fitbit 24/7 and it's collected all of my data, the cals burnt registered from the Fitbit are still likely to be inaccurate? My average cals used last week according to Fitbit was 3508, compared to my TDEE on a simple calculator which is 2352, which I've recalculated for my current weight. That's quite a difference 😳 I feel like the Fitbit should be more accurate as it knows what my body is doing all day long vs a calculator where I've just given some numbers.

I know what you mean, but even though FitBit has all kinds of stats on you, it doesn’t know everything. I think that, in general, calories burnt during more intense types of exercise are likely to be correct, but calories burnt during more everyday activities can be way out.

I once went out for an hour long walk, which my FitBit told me burnt 900 calories...I’m not sure it’s physically possible to even burn that much in an hour, but a walk certainly wouldn’t do that!

Yep Crimson is right, Fitbit waaaay over exaggerates calories burned. Use your TDEE minus 500-1000 cals, which you have been doing and it's been working. I tend to aim for my TDEE minus 750 cals as I can eat well on that amount.

Thank you to everyone for the advice. I've just done all my calculations again, and my TDEE -500 is actually pretty similar to my apparent Fitbit calories -1500. Both calculations come out at around 1800 per day, so that's reassuring.

Going forward I will stick to the advice of TDEE minus around 500-ish and see how the weight loss goes.

Out of interest, how often do you readjust your calorie intake? Is it every time you have a loss? For every half a stone you lose? For everyone stone?

Thanks again 🙏🏼

I’ve been losing weight for about 18 months now and have never adjusted my calories. Weight loss obviously slowed down over time, but I’m in a healthy BMI bracket now, after losing 4 stone, so I don’t really mind if I’m losing at a snail’s pace.

In my case, if I cut my calories too much, I’d just end up sabotaging my diet. So I’ve stuck to 1800 calories throughout. Like you, I’m tall and I’m also very active, so that’s low enough to lose on for me.

Also if you’re looking for some support, feel free to join us on this thread:

www.mumsnet.com/talk/weight_loss_chat/4644025-lose-it-october-202212-week-countdown-to-christmas?page=9&reply=120654595

This thread, and its many predecessors, has been key to keeping me motivated. Everyone is super friendly and it’s the one place where we can talk about our weight loss and the challenges associated with that, without boring anyone 😄

Thanks so much :) I'm the same, if I feel like I'm really depriving myself I end up going off the rails... I need a manageable in between so that I'm not stuffing my face with 4000 cals of rubbish everyday! I'll stick with the 1800 and see how I go. When I did WW I used to drop a point everytime I lost and it was so disheartening!

I've lost so much over the years and put it all back on. I'm in my 40s now and need to be realistic. I'd sooner be 13-14 stone and it's manageable rather than aiming for 11 stone and it's just not gonna happen. Better to be 13-14 than 20!

I'm not overtly active, other than running about at work and having hectic days in general, but seem to burn a lot of cals just being alive lol 😆

I would suggest being in as small a deficit as possible because this is sustainable. With your height and weight, you can definitely afford to eat more and still be in a deficit. I am 5 ft 8, 14.5 stone and lose eating 2100 calories a day :-)
P.S. well done on your loss to date!

Thanks for your message. I wish I'd come to this board when I started! I feel like it might not be good to up my calories at this point as I've been on 1800 for a while :( my TDEE is 2342 so a 500 deficit is 1842 and I'm on 1800. We do have a treat at the weekends which is mostly guess work and being extra good for brekkie and lunch, but I deffo go over at the weekend. I'll stick with the 1800 daily for now as it's quite manageable and I'll not worry about dropping down anytime soon 👍🏼

Its so refreshing to see someone on here say that. I cannot stand when I see the tripe of people gaining weight on 1300 calories 😂