Understanding MFP's Exercise Goal with Weight Loss.

Jubbs89 · July 2014

Hey so I just started back up again and when I was filling out my goals I noticed a weird quirk. My Net calories is set to 1600. I way 249lbs, and I have been working out (before rejoining) 3 days a week for 75 minutes a session. MFP makes my goal 1600 net, and 2040 calories need to be burned. In each session I can allegedly (according to machine readout) burn at least 750 calories off one exercise alone so that is pretty easy. It says that I should lose 2 lbs a week and lose 10 lbs by Sept 3.

Out of curiosity if I changed it to 4 days a week of exercise my calorie burnt goal goes to like 24~2500 calories, which is fine but it still says I am losing 2lbs and lose 10 lbs by Sept 3.

So does MFP just not factor in exercise? If I ate 1600 calories a week and did 0 exercise what would be different? Is the exercise speeding up the process or toning me? I don't get it because my net loss stays 1600

Note: Regardless of answers I am still going to keep working out, this is just a math question that I am asking.

Tillyecl1 · July 2014

Hi, I think I understand what you are asking. The reason the number doesn't change is because, based on the MFP model, you should eat back your exercise calories (which cancels out the deficit created by exercising more).

Although both gym equipment and MFP tend to overestimate calories burned (in my case, based on my HRM they produce estimates around 2 or 3 times what I actually burn) so most people only eat back half of their exercise calories (using the MFP estimates).

If you want a daily number which incorporates exersice (so you don't eat back exercise calories) try the TDEE method instead (calculator can be found at http://scoobysworkshop.com/calorie-calculator/)

Hope that makes sense :-)

MelodyandBarbells · July 2014

No, when MFP calculates your targets it does not factor in your exercise. That information is pretty much an FYI where you can compare if you've met the goals you've set for yourself

Your exercise does come into play when you perform an activity and log it. If you logged the 750 calories from a machine on any given day, MFP will then "credit" you with extra calories you can eat for that day and decreases your "net" calories accordingly.

There are websites where you can calculate your total daily energy expenditure (TDEE), which takes your planned exercise frequency into account in advance, and in addition to all the info MFP asks you. If you setup your MFP account based on TDEE method, then you would eat the same amount everyday regardless of which exercises you do

Beware of calorie burn from machine read outs: they can be insanely high. Many of us use a HEart rate monitor for more accurate data, or just eat back only about half to 3/4 of the calorie burn given by the machines or even suggested by MFP

MinnieInMaine · July 2014

+1 to everything JaneiR36 said.

Jubbs89 · July 2014

Thanks everyone for the answer. Silly question, but why would I want to eat back the calories I burned at the gym?

126siany · July 2014

Thanks everyone for the answer. Silly question, but why would I want to eat back the calories I burned at the gym?

Because eventually eating at such a large deficit can hurt you. You'll be tired, grumpy, starving, perform worse in your workouts, maybe even get sick.

MFP is trying to keep you at a manageable, consistent deficit every day so that you stick with it and lose the weight.

cwolfman13 · July 2014

So does MFP just not factor in exercise?

Bingo...this is why you log exercise after the fact and get those calories to eat back. Your exercise goals are just for you. MFP is NEAT method calculator (Non Exercise Activity Thermogenesis). You will also note that there is no mention of exercise in your activity level...if MFP factored in exercise, it would be in your activity level like any other TDEE method calculator.

You have to account for exercise activity somewhere, that's why you eat back exercise calories...otherwise that activity is otherwise unaccounted for. If you're just walking or whatever, not a big deal...but when you're actually working out, it becomes a bigger issue. Exercise is good for you, but also hard on the body and requires a great deal of energy for repair and recovery from a heavy workout. Just make sure you're not overestimating burn...if you're using a database to get your burn I would suggest only eating back about 1/2 of those calories.

DeguelloTex · July 2014

Thanks everyone for the answer. Silly question, but why would I want to eat back the calories I burned at the gym?

You might not. I don't. Others do.

MelodyandBarbells · July 2014

Thanks everyone for the answer. Silly question, but why would I want to eat back the calories I burned at the gym?

You might not. I don't. Others do.

Very true. For me it gives me flexibility. Sometimes I don't eat all of it. Sometimes I eat way too much. It's extra calories that's a buffer. It also helps transition gently due to the fact that I got fat because I like food, large and tasty quantities of it. If that weren't the case I'd set my account to 1200 calories and be done losing in like two weeks. Okay not quite two weeks but still, very quickly!

leggup · July 2014

Thanks everyone for the answer. Silly question, but why would I want to eat back the calories I burned at the gym?

You can use exercise to build in a bigger deficit (i.e. not eating them back). Some people do that. However, many people see exercise as a way to improve fitness and health.

If you don't eat your calories back, you may burn out. If you're netting way under your maintenance calories you won't be able to continue working out or performing your best because you'll be burned out and weak. Fuel your workouts!

Understanding MFP's Exercise Goal with Weight Loss.

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