Educate me about BMR post-op

[kordie 41]

I am 10 weeks out and have just been looking into my BMR. Apparently my BMR is right around 1700 calories for my weight and height. Right now I am talking in about 700-900 calories a day so way below my BMR. How does this work after having surgery? I don't think I can even get close to 1700 calories in a day. Do we not worry about BMR after surgery or should I be upping my calories? P.S. I have been losing slowly.

[Matt Z 4,140]

2 hours ago, kordie said:

I am 10 weeks out and have just been looking into my BMR. Apparently my BMR is right around 1700 calories for my weight and height. Right now I am talking in about 700-900 calories a day so way below my BMR. How does this work after having surgery? I don't think I can even get close to 1700 calories in a day. Do we not worry about BMR after surgery or should I be upping my calories? P.S. I have been losing slowly.

Yes you need to consider your BMR. Now, you don't need to consume your BMR total, the idea with the BMR is to stay *UNDER* it. Something to note, BMR drops as we age and as we get thinner.

Not knowing your age, based on your height and current weight a BMR of around 1700 would mean you were 53ish.
https://www.active.com/fitness/calculators/bmr

So, if you are eating under your BMR, then you really don't have anything to worry about. Once you get down towards your goal weight, your BMR will have dropped and it should be more attainable to reach a maintenance intake at that point. Things usually do balance out eventually.

[Frustr8 7,886]

I went to the BMR calculator, put in my info,and nothing came up. Am I dead? Dang. I hate THAT-- I'm always the last one to know these things!

[Matt Z 4,140]

21 minutes ago, Frustr8 said:

I went to the BMR calculator, put in my info,and nothing came up. Am I dead? Dang. I hate THAT-- I'm always the last one to know these things!

Did you click on the "calculate" button? LOL
For you, a female that's 5 foot 8, 321 lbs and 72 years old, your BMR is 2033.

[Frustr8 7,886]

I did, I did, I'm sitting here Punch-Dang -Punch'- Dang and just getting my name ---Frustr8ed.,Thank,you Matt

[RickM 1,753]

The thing to watch for with the various online BMR calculators is that they are intended for normal people, not significantly overweight people. BMR most closely correlates to lean body, or muscle, mass rather than overall scale weight - all that extra fat that we carry, or did carry, does little to influence BMR, but can give a false sense of hope by implying that we can lose weight at, say, 2000 calories when we really need to be at 1000 to get the weight off. For my numbers, there is a difference of close to 1000 calories on that calculator between the fat me and the normal weight me, and while scale weight can make some difference when discussing active or moving metabolism, as it takes energy to move that extra fat around, the difference to resting metabolism (BMR) is insignificant.

When using these calculators, it is best to use your "ideal" or goal weight to get a better idea of what your BMR really is.

The other problem is that these calculators seek to tell you what your BMR should be rather than what it actually is, and with the metabolic problems that can accompany severe obesity, that can be a significant difference. Individual testing such as a VOX test is better, but costs more than a free calculator, but can still have some errors as they are still algorithmically based upon normal people. but they are closer.

As for using BMR after WLS, the best way to use it is to simply say "that's interesting" and then ignore it. Keep your calories as moderately low as you can, say 800-1000 calories per day for most, and don't worry about BMR until you get close to your goal weight and need to increase your consumption to stabilize your weight (weight loss history is a better measure of your real world metabolism anyway) or if your weight loss is too slow and you need to adjust your intake downward.

In short, BMR is an interesting number, but not overly useful for us in the form that we usually find it.

[Paul Clarke 108]

I think BMR is useful in trying to help you correlate your caloric intake to your expected weight loss. The general rule of thumb seems to be that you need to have a caloric deficit of 3500 calories to loose 1 lb of weight. My current daily BMR based on my height, weight, age and activity level is 2318. This month my average caloric intake has been 789 calories per day, which means all things being equal I should expect to loose around 0.4lb per day . However that's not to say that I actually do, because there are other factors in play here as well. Since 1st July I have lost 17lb, which is a rate of 0.37lb per day, which means either it is taking me a deficit of 4,229 calories to loose a pound of weight or I am under recording my intake and I am really eating 1,058 or some combination of the two. I think that this is all directionally useful, but is really only one of the indicators that you can use. I like it because it helps keep me on track and gives me a realistic weight loss target to shoot for each month, it also gives me a way of validating the accuracy of my calorie intake recording.

[RickM 1,753]

25 minutes ago, Paul Clarke said:

I think BMR is useful in trying to help you correlate your caloric intake to your expected weight loss. The general rule of thumb seems to be that you need to have a caloric deficit of 3500 calories to loose 1 lb of weight. My current daily BMR based on my height, weight, age and activity level is 2318. This month my average caloric intake has been 789 calories per day, which means all things being equal I should expect to loose around 0.4lb per day . However that's not to say that I actually do, because there are other factors in play here as well. Since 1st July I have lost 17lb, which is a rate of 0.37lb per day, which means either it is taking me a deficit of 4,229 calories to loose a pound of weight or I am under recording my intake and I am really eating 1,058 or some combination of the two. I think that this is all directionally useful, but is really only one of the indicators that you can use. I like it because it helps keep me on track and gives me a realistic weight loss target to shoot for each month, it also gives me a way of validating the accuracy of my calorie intake recording.

Yes, I kinda went with the reverse of that when working into maintenance, taking my average loss of 10lb per month in the prior 2-3 months and extrapolated that out to being a caloric deficit of around 1000 calories per day, which worked out fairly close as I had been consuming 1100 calories per day on average, and wound up maintaining in the 2000-2200 range. BMR is stated to be in the 17-1900 range depending upon what formula is used, and activity burn is the really big variable - no one has a decent handle on that one for us fatties/former fatties. Using the typical lifestyle or activity intensity factors would give me numbers several hundred calories higher than what my real world metabolism produces.

[kordie 41]

17 hours ago, Matt Z said:

Yes you need to consider your BMR. Now, you don't need to consume your BMR total, the idea with the BMR is to stay *UNDER* it. Something to note, BMR drops as we age and as we get thinner.

Not knowing your age, based on your height and current weight a BMR of around 1700 would mean you were 53ish.
https://www.active.com/fitness/calculators/bmr

So, if you are eating under your BMR, then you really don't have anything to worry about. Once you get down towards your goal weight, your BMR will have dropped and it should be more attainable to reach a maintenance intake at that point. Things usually do balance out eventually.

Nope...not 53! Try again... LOL! I am 43 and female so that puts me at about 1750. I like the idea of using the ideal weight for BMR, that puts me at about 1350. I'm definitely under that! Thanks everyone for the advice/discussion!

[Sleeved36 356]

What about those fancy scales that use impedance to calculate body mass and BMR. Not the home ones.

I used 1 at the hospital. How accurate are those postop?

[RickM 1,753]

1 hour ago, Sleeved36 said:

What about those fancy scales that use impedance to calculate body mass and BMR. Not the home ones.

I used 1 at the hospital. How accurate are those postop?

Actually, I find a home impedance scale to be better than the ones at the doctor's office. The reason here is that they are sensitive to your hydration, so you can easily see a difference of maybe five points on the body fat reading between first thing in the morning when you are typically dehydrated from sleeping, and late afternoon when you are usually fully hydrated (the late afternoon reading is generally taken to be the more accurate one.) If you use one at home, at the same time each day, you may see some variation day to day due to hydration fluctuations, but if you average it out over a week, it is pretty good; if you just do a measurement at the doctor's office, it is just a snapshot and you don't really know if the reading is on the high or low side, or just about right.

When I was losing, I basically took a mental moving average of the readings. Typically, my BF% may be, say, in the 33-34% range and it would fluctuate around there but I didn't put any great significance in the individual readings. In a couple of weeks, I would start seeing readings in the 32's, and then no more in the 34's - so that I took as a good indication of progress - I went from 33-34 down to 32-33, so call it down a point in those couple weeks; a reading of 32.5 one day and 33.5 the next doesn't carry any real significance.

One can calibrate these readings by comparing them to a Water dunking or DEXA scan test, which isn't a bad idea every six months or so while things are moving, or at least as you get closer to goal weight (though those tests can have their own errors, though generally smaller) and for me, at least, they correlated fairly well to my moving average readings.

The BMR readings on the scales will be somewhat better than the online calculators as they are taking body composition into account, but I wouldn't depend on them too much in figuring out how much you should be consuming to lose that last 10 lb.