TDEE -20% is lower than BMR - what to aim for?

jumblejups

I've used MFP before for tracking and worked out my needs based on the stickied guides, but I've become a bit stuck now. I'm returning to MFP having had a second baby (so this isn't a "I used to track, lost weight, gained it all, now I'm back" post - well, not in the typical sense anyway!). I was part of the way through losing weight when I got pregnant so there is the pregnancy weight to lose and then the original weight loss goal.

Some info: female, 25yo, 162cm, 180lb. I've been tracking for 4 weeks and started at 188lb - first week had a 4lb loss, I'm guessing water weight involved, after that it has steadied a bit more and last two weeks have seen a loss of around 1lb per week. My current goal is 140lb which is what I was aiming for pre-pregnancy. I am not particularly active - I'm not working as I'm on maternity leave and I'm only slowly introducing exercise whilst I regain strength post-pregnancy and due to an existing health condition I have. However, with the occasional exercise I have done I am eating back 50% of calories based on MFP's calculations and seeing how that works. Exercise isn't regular at the moment to make me want to reconsider activity levels for TDEE so I choose the lowest activity level.

I use Scooby's Workshop and IIFYM calculators, both of which have put me around 1545 for BMR and 1855 for TDEE. Until now I was set at 1500 calories/day but that would put me below my BMR. TDEE -20% would also put me below my BMR. TDEE -15% would put me just over, at around 1575 calories/day. MFP would put me at 1200 cals/day which just seems crazy aggressive to me.

I can reset my goal to 1575 calories/day and increase my consumption. I'm fairly healthy in the types of food I eat (with some dark chocolate treats!) and I know I could easily make up the extra few calories with more vegetables, fruit, nuts, or more calorie dense foods, that kind of thing. I'm just wondering about my weight loss approach here - I'm looking at a deficit of 280 cals/day or 1960 cals/week. It sounds like a small deficit, but then I'm guessing that's about right given my stats? Also it's only just a bit over my BMR, so I'm wondering if that's okay or if I should be going for a smaller deficit still?

I was originally aiming for around 1-2lb per week, so with my new goal I'm wondering if it will be slower, around 0.5-1lb per week? I have 40lb to lose and expect my weight loss to gradually slow as I get closer to my goal, part of me is wondering if it will reach glacial at some point at this rate I don't mind, a steady healthy loss is the only way, I'm just trying to get my head around what to expect.

So after that long post, I'm really just looking for some experiences from others or reassurance that I'm plugging the numbers in right and going about this in the right way. With time I will be more active and I aim to eventually incorporate more in the way of strength training too and not just cardio so I know that will have a positive impact, but this is where I'm at for now.

MinnieInMaine

With only a 45 cal difference, I don't think it's a big deal for you to set your goal for 1500 calories per day. The concern there is more for folks who have a larger discrepancy between the two, usually because they have less to lose and therefore 20% may not be the most appropriate deficit. When you do exercise or have a more active day, make sure you log it and eat back at least half of the earned calories since your TDEE doesn't include exercise.

segacs

The whole "don't eat below your BMR" thing is a myth. I have no idea how it got started. But TDEE-20% is a reasonable, healthy deficit, so don't stress about it.

Are you exercising? Usually, if you add exercise, TDEE-20% ends up being above BMR.

And 0.5-1lb/week is a perfectly reasonable pace of weight loss. Try to set up your expectations for this to be a slow, sustainable process as part of a lifestyle change.

mymodernbabylon

Also - are you doing activity outside of just exercise? Do you run errands, walk a dog, walk around with your baby or have other kids to chase around? This should also be included in your TDEE activity levels. You don't have a huge amount to lose so a .5 to 1 lb loss a week is very reasonable.

jumblejups

Interesting, okay. I'm now searching about eating below BMR - I had just sort of taken it as a Serious Thing, my metabolism is slow anyway due to my health condition so I probably panic a bit about doing things 'wrong'.

As in my OP I don't mind having a loss of 0.5/1lb, was just wondering if that's where I'd be with a 280 cal/day deficit. I don't really know what to expect with any of these deficits! I am looking for slow and steady and just want to make sure I do it right. As above I'm not on regular exercise yet but when I do I eat back at least 50% of the calories and I'm seeing how that works (don't currently have a HRM/any other way to try and more accurately calculate calories burned so I'm going off of the MFP database).

TimothyFish

If you don't exercise, you're probably going to have to eat below BMR to lose weight, since most of your calories burned are BMR.

segacs

In theory, a 280/day calorie deficit would put you at around 0.5-0.6lbs/week.

But remember, in practice it's never going to be that precise. Calculators are only estimates; your actual TDEE will fluctuate and may be higher or lower than the calculated value. Also, it's unlikely that you will eat exactly the same number of calories every single day... some days will be a big higher, some lower, as long as you come in around or just under your weekly goals, you should be good. Plus, every time you step on the scale, your weight will fluctuate a bit -- time of day, time of month, water retention, you name it. It's just not that precise a science.

Try eating at that level for 4-6 weeks, track and log your weight loss, and then adjust: If you're losing too fast, eat more. If you're losing too slowly, drop the calories by another 100 or so and see how that does.

bug1114

I've always heard not to eat below your BMR. When I was in the situation where TDEE was under my BMR, I was told to eat at least 100 calories more than my BMR. There's a post somewhere on the message boards that explains it, it used to be a sticky but I think they renamed them to "announcements".

jumblejups

I am active outside of exercise but I don't think it would be much different from a desk job (going by the labels for activity and desk job being lowest). I have a toddler and I walk to and from his childcare but it's not that far (about 0.5mi away), I walk once a week to a different session of his which is 1mi away, and to another place 1-2x a week which is also 1mi away. Sometimes I walk to other places about 2mi away. I go at an average walking pace.

I've done that for a long time (walked more when I was working as I walked part of my journey to work), so I never really think about it. When I'm not walking I don't do very much at the moment, it's mainly feed baby, change nappy, play with toy cars... a lot of sitting down and not much running around, even tickles tend to happen on the sofa! So I don't think my walking makes a huge difference when taken together with my inactivity the rest of the time. Eg today I got a lie in (yay for me), got up, put toddler down for a nap, made a coffee, and have generally not done much else in terms of activity. I'll make dinner and do some tidying and that's pretty much it, with some feeding and nappy changes and toy cars/dinosaurs/shape sorting thrown in there.

jumblejups

To be clear, childcare is only 2 days/week.

segacs

Instead of thinking about the various activities, just log and monitor real world results for a couple of months. In 60-90 days you can get a very good idea of the range in which your TDEE usually hovers. Just measure actual calories consumed and actual weight lost, and do the math. Then you'll know and you can take some of the guesswork out of it.

(Remember your TDEE will get smaller as you get smaller. It takes less energy to sustain a smaller body.)

jumblejups

Thanks for all of the input, I'm going to try this out (seeing how it goes for several weeks, and adjust if necessary) and I'm looking for the announcements to understand a bit more too.

lemurcat12

segacs wrote: »

The whole "don't eat below your BMR" thing is a myth. I have no idea how it got started. But TDEE-20% is a reasonable, healthy deficit, so don't stress about it.

Are you exercising? Usually, if you add exercise, TDEE-20% ends up being above BMR.

And 0.5-1lb/week is a perfectly reasonable pace of weight loss. Try to set up your expectations for this to be a slow, sustainable process as part of a lifestyle change.

This. I'll add that I'm the same height as you, although older, and at close to 1600 I would not lose without exercise at my current weight (close to goal), so it slowing down or being lost in the imprecision of counting is possible.

If you are okay with taking it slow, however, I'd just go with it and adjust as you need.

If you want to make it a bit faster, adding exercise (which should be included when figuring out what your TDEE is) or going below BMR are both fine ways. Just keep the deficit itself reasonably moderate (which 20% or less would be at your current weight).

bug1114

Here's the link for the post I was referring to. There is a group called Eat More to Weigh Less on here that has all of this information in it.

http://community.myfitnesspal.com/en/discussion/512956/tdee-what-is-it-and-why-you-should-not-eat-below-your-bmr/p1