Doing TDEE minus 20% in MFP - I don't get why you would

CorvusCorax77 · February 2013

I was looking over the numbers that I might want to use if I took my BMR and fed it into the Harris Benedict Equation to get my approximate TDEE. If I then take 20% off as suggested here, that is theoretically my goal caloric intake if I keep my exercise steady at the current rate.

So far so good - I compared it to what I've been doing and it seems pretty close to what I've been doing in MFP, which is a net calorie thing (food minus exercise).

What I don't understand is why anyone would use the TDEE methodology and use myFitnessPal. This method assumes that you don't eat back any calories because caloric daily goal already accounts for your assumed exercise activities.

So, my TDEE -20% is 2500 calories, do I put 2500 calories as my daily goal?

How are people using MFP meaningfully then? Are you still recording your exercise and food and just ignoring all the numbers MFP tells you other than total calories eaten?

My current methodology is to enter everything and actually use MFP's numbers as a guideline for how much to eat or not eat and how well or poorly I'm doing for the week. I let MFP set my net calorie goal (1750 currently). When I eat food it goes down and when I exercise it goes up. I track everything and see everything in MFP and all of the numbers are meaningful. I can look at the various reports of average net calories and can look at all of the exercises I've been doing.

Am I missing something? It just seems weird to me to use only a small fraction of the functionality MFP offers because you aren't letting MFP do what it is best at.

MFP hs the option to edit your goals. I have it set up for my TDEE (1700 cals) and my protein goal at a specific # (120g's of protein a day). I track all my food.

Yes it's meaningful.

I also track my exercise, as in I log it. But i also write it down on paper. When I log it, I log it as a "new exercise" under "my exercises" and write what I did, how long, and give myself 1 calorie for it.

It's nice to post "CC burned 1 calorie doing 60 minutes of cardio including "strength training".." and then having people say "WAY TO GO!"

CorvusCorax77 · February 2013

I also like to brag about new PR's, NSV's, and interact and learn from other people on here who are AMAZEBALLS (like Taso, there.)

TAsunder · February 2013

Thanks, all. I'm starting to get it now. I don't plan on switching my methodology unless the numbers MFP tells me start to differ greatly.

If you are doing TDEE, I assume that you have to re-calculate when your lifestyle changes (e.g. during recovery from surgery)?

love4fitnesslove4food_wechange · February 2013

Everyone is different and you have to do what works for you. I use the TDEE - 20% = 1017 c. It is the only thing that works for me.

I agree - if it works for you then do it. I just don't get how it works with myfitnesspal. It seems like you would only be using it to count calories eaten. Is that correct?

That is correct. You wouldn't use the numbers that MFP gives you if you were going by the TDEE method. I actually set my net to 0 so that I can SEE what I'm eating, burning, and calculate things in a simpler fashion.

rileysowner · February 2013

The reason I use TDEE - 20 is because my experience, even using a HRM, is if I do the eat back calories thing I am eating way more than TDEE-20 and not losing. This makes me think that the calories calculated are too high which is the case when you exercise a long period of time since the longer you exercise the higher your HR tends to go resulting in an over calculation of calories. This would definitely be the case with my 2 hour bike rides. I also prefer simply eating the same amount of calories every day. MFP is a tracking tool, and that is what I use it for.

kgavins25 · February 2013

Being a Civil Engineer, and interested in math,I started to do this... Plugging in current weight, height,age, very little activity(desk job)etc to get my BMR,

BMR= 1600
TDEE= BMR x 1.2(little activity)= 1600 x 1.2= 1920 (to maintain)
x 1.55( 3-5 workout days)= 1600 x 1.55= 2480 (to maintain)

So I reduced by a safe number of 20% (to loose)
1920 x .20= 384 2480x.20= 496
1920-384= 1536 2480-496= 1984

So adjusting MFP numbers to 1/2 lb a week, little exercise, gave me similar numbers. So thats my goal to stick to when im not able to work out. Otherwise, that 1.55 factor will be calculated and therefore be my goal.

cwolfman13 · February 2013

Everyone is different and you have to do what works for you. I use the TDEE - 20% = 1017 c. It is the only thing that works for me.

I agree - if it works for you then do it. I just don't get how it works with myfitnesspal. It seems like you would only be using it to count calories eaten. Is that correct?

I use the TDEE method. I still need a calorie tracker and I need a macro tracker...I also need to track certain micros like saturated fats and sodium. What functionality I'm I missing out on? When I was using the MFP method and logging exercise and eating those calories back, I was at exact same gross calorie goal over a weeks time as I am now using the TDEE method. The biggest difference for me is that I just eat my 2,150 calories (my custom goal in MFP) per day throughout the week (includes all of my exercise)...it's not 2,000 one day and 2,300 on heavier workout days, etc like it was with the MFP method....it's flat and nets out over the course of the week. This helps me immensely in planning my meals...I also don't have to be scrambling for some way to make up 300-400 calories at the end of the day when I'm not really all that hungry.

There is of course one caveat...you have to have a workout routine down pretty pat and you can't cheat...skip days, etc otherwise your formula is off. Obviously, you have to adjust your goals if you know you're going to be out of commission or whatever...if I know I'm not going to be able to get my regular exercise in, I just dial it back to 1,900.

At this stage of the game, I have a routine...I know by months of experience that on average I burn about 1,800 calories per week doing exercise. I know this is about 10% of my calorie burn weekly. I know that 70% of my weekly calorie burn comes from BMR and about 20% from just day to day activity...so it all comes out in the wash over the course of a week. Basically I track daily, but I'm really looking at things week to week rather than day to day.

I would have struggled mightily with the TDEE method in the beginning because a.) I didn't really understand what all of that meant so it was a lot easier for me to just have a set goal by MFP, and 2) my exercise wasn't routine at all...I'd miss days or go light for a couple days, etc....my burns were all over the place and it would have been impossible to do the TDEE method. I basically exercised a good bit when I wanted to eat a bit more. Now, my fitness goals, while they may run parallel with my weight loss goals, are really completely separate goals and I exercise for my fitness, heart health, endurance, and strength...not necessarily for weight control or so that I can have an extra treat at night or something.

CorvusCorax77 · February 2013

Thanks, all. I'm starting to get it now. I don't plan on switching my methodology unless the numbers MFP tells me start to differ greatly.

If you are doing TDEE, I assume that you have to re-calculate when your lifestyle changes (e.g. during recovery from surgery)?

TDEE is based on your activity level, so yeah. If you become less active then you have to recalculate. Likewise, recalculate when your weight changes.

CoderGal · February 2013

If I then take 20% off as suggested here, that is theoretically my goal caloric intake if I keep my exercise steady at the current rate.

Not necessarily. It's just 20% of your TDEE in other words = BMR*activityLevel*.8. Less then your energy expenditure, therefore you'll lose weight. If that happens to be your goal TDEE, well, that's just freaky.

So far so good - I compared it to what I've been doing and it seems pretty close to what I've been doing in MFP, which is a net calorie thing (food minus exercise).

It should be more along the lines of food PLUS exercise, not minus.

What I don't understand is why anyone would use the TDEE methodology and use myFitnessPal

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myFitnessPal uses the TDEE methodology (how do you think it gets those numbers? Most people just set it up incorrectly since it is basing it on inaccurate weekly weight loss values). You can use the method that assumes you do not eat back any calories when you set up MFP.

To explain the weekly weight loss values, it assumes you need to take off 500 calories a day from your TDEE to lose a lb a week. That would be a significant amount below the amount needed to perform basil functions for someone who doesn't have a lot to lose. 500 is a lot to some people and not so much for others. If you're nearly under weight you'll find you'll likely hardly lose any, if you're over weight you'll probably find you'll lose a lot more. There's water to be lost as well and the heavier you are the easier that drops off. Not to mention just because 3500=1lb of fat (while true) doesn't necessarily mean that every lb of weight you lose is coming from fat.

So, my TDEE -20% is 2500 calories, do I put 2500 calories as my daily goal?

Yep. If you want. Personally I set it up so my goal is my sedentary TDEE so then I can add activities from there. Both work. Both end up being around TDEE-small%

How are people using MFP meaningfully then? Are you still recording your exercise and food and just ignoring all the numbers MFP tells you other than total calories eaten?

Since I am using my sedentary TDEE and do not have exercise included, I log them. I could set it up so that I wouldn't have to but I enjoy logging them. But you could set it up as your actual TDEE and log exercises as 1 cal if you like (so the burn is negligible).

I let MFP set my net calorie goal (1750 currently)

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Yikes, I'm nearly a underweight female and eat more then that. To give you an idea of 'normal' calorie intake, the RDI recommends 2500 calories for a healthy male to get most of their required nutrition. If you're eating your exercise cals back that's not so bad.

When I eat food it goes down and when I exercise it goes up. I track everything and see everything in MFP and all of the numbers are meaningful. I can look at the various reports of average net calories and can look at all of the exercises I've been doing.

If you enjoy enjoy making the graphs go up and down I suggest setting your goal as your sedentary TDEE - small% and logging exercise and eating them back. Though you still have the same data if you choose the alternative way to do it.

Another alternative is set it to your actual current TDEE and just make sure you eat BELOW that. Or set it to your current sedentary TDEE, log exercises, and make sure to eat BELOW that. That way a lot of people stop freaking out when it goes into the read making them think they're getting fat when they're still on a significant deficit.

Mostly the manual TDEE method was just explained to people so people knew what and why they were doing what they were doing. Not to mention it's a lot easier to customize things to their needs. Initially I signed up and since I didn't know how the data was being used I punched in a lb a week and set myself to sedentary and my values plummeted to minimums. The math MFP uses doesn't take into account body fat percentages either. Once I learned the TDEE stuff I had more control over things and knew exactly what I was doing to myself. There was no little black box with blue smoke.

Hope this helps