Confused about BMR

bgt84
bgt84 Posts: 7
in Health and Weight Loss
Hi all,

I'm a 28-year-old male, 6' 1" tall, 220 lbs. I'm trying to get down to about 185 lbs, from a starting weight of near 250 lbs. I walk 30 minutes on a treadmill 5-6 times a week (10 minutes at 4.1mph, 3% incline; 10 minutes at 3.7mph, 10% incline; 10 minutes at 4.1mph, 3% incline). I've had some success so far (I've lost 30 lbs since mid-October) but I've been reading a lot about basal metabolic rate and I'm thoroughly confused. MFP suggests that to lose two pounds per week I should eat about 1,550 calories (plus about 300 calories from exercise, for 1,850 total on days that I exercise), which is what I've been trying to follow. However, all the basal metabolic rate calculators that I've seen have calculated my BMR as somewhere around 2,200 calories per day.

I'm worried that by eating only 1,550 - 1,850 calories, I'm going to end up in "starvation mode" or messing up my metabolism somehow. But my understanding is that MFP's weight-loss calculator takes into account my BMR somehow. At this point the weight is still coming off (albeit a little more slowly than at the start), but I'm concerned about doing damage by not eating enough calories in a day. Should I be eating more than I am? Or is what I'm doing okay?

Thanks!

Replies

  • KittyViolet
    KittyViolet Posts: 220 Member
    I would definitely up your calories. You're a tall, tall guy, hon. MY BMR at 5'1" is 1500. So for you to eat the equivalent of what my little body needs at its lowest level of activity doesn't make a lot of sense. Try changing your weight loss goals on MFP to 1 lb. per week and see what numbers it gives you. I know it's very tempting to lose a lot of weight very quickly, but this kind of stuff takes time. You can't rush it.
  • mjrkearney
    mjrkearney Posts: 408 Member
    MFP calculates your recommended daily intake by taking what it estimates is your TDEE (BMR + routine burn) then subtracting the number of calories you would need to burn the weight you requested. This can easily put you below your BMR. That being said, all calculators are not created equal. Without an extensive study you might never know your true BMR which would also fluctuate with your weight.

    Basically, if you're worried about starvation mode, increase your calories slowly to where you're losing at a comfortable rate.
  • cwolfman13
    cwolfman13 Posts: 41,865 Member
    MFP's calculator does not take into account your BMR (though they do have a BMR calculator). Knowing and understanding your BMR is a personal responsibility, MFP gives no warning as to whether you're eating below your BMR or not. Everyone likes to pick the most aggressive weight loss approach which is 2 Lbs per week...but really, unless you have 50+ Lbs to lose, 2 Lbs per week is too aggressive, at least that has been my personal experience. With 50+ to lose, one can usually have a wide enough gap between their BMR and TDEE to sustain a 1,000 calorie per day deficit. Also, someone with 50+ Lbs of fat to lose has a lot of fat stores to make up for that deficit so they can often net below their BMR for longer without ill effects.

    When you start losing weight, that gap narrows...so 2 Lbs per day becomes no longer sustainable. It also becomes more important to net to your BMR because your body no longer has the fat stores to properly function below that number. A good general rule of thumb:

    50+ Lbs - 2 Lbs per week loss goal
    20-50 Lbs - 1.5 Lbs per week loss goal
    10-20 Lbs - 1 Lb per week loss goal
    0-10 Lbs - 1/2 Lb per week loss goal

    MFP really does leave it up to the user to figure this stuff out unfortunately. BTW, I'm 5'10" and lose roughly 1 Lb per week at about 2,150 calories. I use the TDEE method now as my exercise routine is well established and I know roughly how much I burn per week with exercise and how much I need to cut in my diet to get to my desired weight loss goal without going below my BMR.
  • bgt84
    bgt84 Posts: 7
    Hi all,

    Thanks for the replies. You seem to have confirmed what had been my gut feeling -- that I was eating too few calories. Like I said, I'm down 30 pounds or so, but the past 2-3 weeks I seem to have plateaued and haven't lost too much at all. I'm assuming my body may have entered or at least begun to enter starvation mode. I'm thinking of bumping my calorie intake up to 2000-2200 calories per day or thereabouts. Does that sound more reasonable?

    It seems that most calorie calculators tell me my normal daily calorie burn based on my activity level is 3100-3300 calories, so it sounds like I have a fair bit of leeway in my calorie intake to continue to lose some weight.

    My other question is, if my body has got into starvation mode, what do I do? If I bump up my calorie intake to 2200 cals/day, will it eventually "get back to normal"? Or do I need to raise my calorie intake further? And how long does it take? Am I talking days, weeks, months?

    Thanks again!
  • RobinvdM
    RobinvdM Posts: 634 Member
    There is no such thing as starvation mode, it's a misnomer. Your body may have just decided to start hanging onto the food a bit longer than it usually would have due to noticing you are getting serious about cutting calories. Even so, I wouldn't think this is the case unless you have been plateauing for a considerable amount of time.

    I would use one of the online BMR calculators to figure out what your "at rest calories" really are. Then figure in the workout calories you are burning, and make a point to eat those back - your body needs fuel to function, your body fat isn't enough unless you want to burn off some lean body mass while you are at it (something, I am learning recently, is not such a great thing.)

    All you have to do to get your body back on track is eat consistently. Make sure you eat a few more calories on your workout days, and BE PATIENT. It will work out.

Categories