Big difference between TDEE - 20% and MFP + Exercise?

steskey

Hi all,

So I've read a lot of the FAQs and old threads on this topic, but I still have a couple of questions.

I have been using MFP for a few months, lost a few pounds, but I completely plateaued once I started running regularly. I started with C25K, finished the program, and now run around 10 miles a week varying long and short runs 3-5 times a week. Now, I have ALWAYS eaten back my exercise calories as I understand the problems with creating too large of a deficit and the impact it can have on my running performance. I am training for distance and plan to continue adding miles. I want to be at around 20 miles a week in a few months

I don't think my plateau is caused by eating exercise calories. I think my plateau is caused by the fact that I have cheated (gone above and beyond the base + exercise cals) ALMOST EVERY SINGLE WEEK since I started running.

I feel hungry pretty much constantly. I'll do fine during the day, but once night hits (especially after the long runs) I am ravenous and binge. I always log and I usually end up anywhere from 1000 - 3000 over my goal each week.

According to MFP, I am "lightly active" (I have a job where I am on my feet most of the day) and it puts my base at 1500 for losing 1 pound a week. I put in my runs and I get an average of about 300 burned per run (more or less) which comes out to about 900, maybe 1000 a week in exercise calories. This puts my total average that I'm burning at around 1642 per day, correct?

I've used a couple of the recommended calculators for TDEE, always putting in "Moderate" (Exercise 3-5 times a week) and my TDEE maintenance is usually at around 2400 - 2500 while my TDEE - 20% falls around 1900 - 2000.

I've decided to try the TDEE - 20% this week (not entering exercise, of course) and see how it works. I want to see if this is a more sustainable method for me. The issue is that the difference between the MFP calculation and TDEE - 20% seems huge! 1900 versus 1642? I feel like I'll be lucky lose 0.5 a week with this method.

I guess my question is whether or not MFP is underestimating or the TDEE calculators or overestimating. It's hard to tell since i haven't really followed the plan at all in a few months. Should I just try out TDEE and see? What do you think?

Thanks!

natini

I think MFP is underestamating. I have an office job and I am lightly active in MFP. I think you are higher than lightly active. I would definately try the TDEE - 20% this week and maybe for two weeks. You will probably feel so much better by eating more and fueling your workouts. I like the TDEE - 20% better than MFP and eating back execise. I prefer to eat one calorie goal everyday.

heybales

So MFP has non-exercise TDEE as 2000, and BMR as 1480. So barely eating above BMR, meaning hardly anything left to make improvements with, probably not enough for resting metabolism.
1000 exercise calories a week / 7 = 143
Total TDEE 2143.

Other sites have exercise TDEE as 2450 and BMR as 1580 (would that happen to be fat2fit with their inflated Harris BMR? I'd trust Mifflin's BMR on MFP more).

So the basis for the math is probably different. Mifflin that MFP uses is better than Harris. And Katch based on bodyfat% better than either.
You are taking less deficit too with 20% off method, from bigger inflated value.

Depending on how you get those exercise burns running, if HRM and your are not more cardio fit, you are most likely getting badly underestimated burns to count as eat-back calories.
Of course you don't do it that way using TDEE Deficit method.

With moderate amount of exercise, the 2 methods actually do about equal. Potentially inflated calorie burns balance out the other days really eating probably too low.
Infrequent or irregular benefits the MFP method, though the daily amount could be too low and that backfires.
Lot's of exercise benefits the TDEE Deficit method, other wise eating back too much with MFP method.