Doing the math: Eat more, lose more test run and questions

I was inspired by this thread...

After figuring my own body fat percentage and basal metabolic rate, I discovered MFP was actually asking me to eat fewer calories than my estimated BMR. I should be eating more to lose more, according to my math. I was previously eating 1800 calories per MFP recommendations, and now I am bumping that up to 2250.

Since I am setting my own custom calorie target, I want to make sure I am starting out within a healthy range. Doing the body fat/BMR calculation I came up with the following calorie targets...

BMR: 2010
Sedentary lifestyle: 2990
Lightly active: 3427

I am nursing a back injury, so my current workout regiment is lap swimming for 20-25 minutes three or four times a week. I don't know if this qualifies me as sedentary or lightly active, since I am not working currently. I shot for the middle, taking 3208 calories as my maintenance goal. Reducing that by 30% I came up with 2250 for my daily calorie target. Is that a safe starting point for a custom calorie target? If I am truly "lightly active" then that gives me a weekly calorie deficit of 8239 (3427-2250=1177x7=8239), or 2.35 pounds a week. As I said, I was eating 1800 calories using the calorie target calculator on MFP, which is 200 calories a day below my calculated BMR. That can't be healthy or safe, can it? I want to lose fat, not muscle.

Also, since I have this back injury, weight lifting of the muscle building kind is probably off limits. I am going to consult my doctor about that soon, but would it be worthwhile to buy a dumbbell set with variable weight plates up to say 40 pounds and start doing some light lifting with those? Or do I really need to do the max weight/low rep workouts always being promoted here to see any benefit from weight training? I've also considered doing some body weight muscle exercises like pushups.


  • CupcakeHarpy
    CupcakeHarpy Posts: 100 Member
    Just as a note: I don't claim to be a know it all but this is what I found works for me.

    I have a back injury and do swimming also. Since I'm not on my feet most of the day (lightly active) I set my goals to sedentary (I work out but I sit at a desk most of the time). My bmr is about 1877 and my tdee is about 2200 (assuming I'm sedentary). So I aim for anything between those two numbers. I don't really log my exercise. But if you do, you can eat those calories back up to your bmr to make sure you are getting enough food. Really, you have to find out what works best for you. Everyone is different but maybe try this as a starting point. LOG EVERYTHING and be as accurate as possible to know if what you are doing should be changed. Another tip: mfp calories burned for exercise is way off. If you log your workouts get a heart rate monitor to find out what you are really burning. Other than that, try to eat your calories with whole healthy foods, which goes without saying. good luck.

    I can't really help with the exercise bit. Sorry. I only do what I feel my body can do. When my back is feeling better, I'm going to consult someone. Probably a personal trainer. Get your doctor's ok before buying anything. Then invest in at least 1 good personal training session with someone to guide you in the right direction. It is worth the investment more than hurting yourself again. best wishes.
  • onefournine
    Thanks for the response. I calculated that I had a range of calorie targets between 2100 and 2400 that would allow me safe weight loss from 1 to 2 pounds a week, assuming I was sedentary on the 2100 end and lightly active on the 2400 end. Anything above my calculated 2000 calorie BMR should be healthy fat loss. I guess I am just going to have to try it for a couple of weeks and see how much, if any, adjustment needs to be made. Right now at 1800 calories, I am not losing.
  • CupcakeHarpy
    CupcakeHarpy Posts: 100 Member
    Definitely raise your calories to 2000 min and see what happens. If you are having trouble getting that number up there, you can snack on some fatty (but healthy) foods like nuts or add olive oil to salads or coconut oil to stir frys. Don't be afraid of good fats. But if you are recording everything you can be sure that you're not getting too much of a good thing and going over calories.
  • daisyelaine
    daisyelaine Posts: 480 Member
  • yarwell
    yarwell Posts: 10,477 Member
    which is 200 calories a day below my calculated BMR. That can't be healthy or safe, can it? I want to lose fat, not muscle.
    There is no published data that shows any specific effect of eating above or below your estimated BMR.

    Low losses of fat-free mass are sometimes recorded with high calorie deficits and high protein.