BMR confusion

Thimbelinda

Many places on these boards I have read, never eat under BMR. So I am really confused by the following recommendations.

My nutritionist had met eating almost 500 calories below BMR
MFP had me eating more than 300 below BMR when set to lose 1.5 pounds a week, activity level sedentary.
Scoobysworkshop has me eating 66 calories below BMR, when set up as low activity level/desk job TDEE -20%

Where does this recommendation to never eat below BMR come from and why is it important?

AJ_G

It would be helpful if you would include your BMR and your TDEE so we have an example to work with, but anyway, the "don't eat below your BMR" rule that seemingly came out of thin air arises from people worried about "starvation mode" and thinking that your body will hold on to fat stores if you eat too little. This isn't the case, at least not in the short term. I would like to know why your nutritionist had you eating 500 calories below your BMR, that seems pretty drastic. The one from scoobysworkshop sounds about right if you set your activity level to sedentary. The way TDEE calculators work is they calculate your BMR then multiply that by an activity factor to get your TDEE. The lowest activity multiplier is 1.2 so if you multiply your BMR by 1.2 then proceed to subtract 20% from your TDEE that would leave you with 96% of your BMR calories so you would be eating below your BMR. any of the activity factors greater than this will have you eating above your BMR. While it's ok to eat below your BMR, make sure you don't have too drastic of a calorie deficit because over time this will effect you negatively, because your metabolism adapts, but it is a slow process

loubidy

500kcal under your BMR?! Thats a bit drastic!! My BMR is 1430kcal, my fitness advisor who designed my fat loss programme told me I shouldn't eat far below it if at all so I usually eat around 100 under but thats to allow for miscounts.

sarafischbach9

Generally, a diet under your BMR is considered too low. I mean, a day or two a couple hundred under won't kill you but in the long term you might have some issues down the road. I would at least eat at your BMR or a few hundred over if you do decide to incorporate an exercise program down the road.

I am surprised your nutritionist would put you on a diet that is well below your BMR.

IMO, a diet that is too low might make you feel deprived, which can turn into binges later on. And then the whole yo yo dieting thing. I think it's better to just eat a little more, exercise a little, and lose weight slower than eat an insane low amount of calories.

A lot of people say that you shouldn't eat under your BMR in case you go into "starvation mode." I think a good rule of thumb is to eat at your BMR at the very least is that is the amount you need for your daily functions of the body. You will still lose weight; not sure why you are told to go down so low.

MY BMR is 1200-something ( in between 1200-1300 ) and I could not imagine eating under 1200 calories every single day.