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How do you determine lean body mass?

Hello, all!

First time in a long time I am going to ask a question, but I wanted to pick people's brains.

Ok, I am 5'2" and 204.6 lbs and my hubby is 5'7" and 209.6 lbs.

On page 192 in Geek to Freak, do the Slow Carbers have to follow the protein gram amount for the "lean mass" in order to build muscle?

One of the mistakes people make is not getting enough protein, but how much is ENOUGH protein for your particular body? I think that part is kinda confusing to me and I'd like to get an exact answer from someone who may be more "in the know" than I.

I think my husband and I get around 100g-125g of protein daily depending on the day. We definitely get our 30g of protein in the morning. It's just Lunch and Dinner vary and we're pretty much eating beef, fish, and chicken.

Please help me answer this question to see if I have to tweak the diet for myself or my husband so we can maximize our fat burn and muscle building.



The Best Answer

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Lean body mass can be determined in a variety of ways. There are estimators out there that use algorithms similar to a BMI test that takes into account your weight, your gender, and your height to determine your lean body mass. If you'd like a rough estimation, try this online one: http://www.healthstatus.com/calculate/lean-body-mass

To get a more accurate picture, you can get tested. I recently got my BF tested at school in a Bod Pod. It was quick and it gave me a print out of my lean muscle mass and fat mass, as well as my resting metabolic rate. It's pretty handy if you can get the test done. I've compared my Bod Pod testing with the online estimator I just sent to you, and the % error, according to my stats, is about 3-4%, so I'd say it's a fairly accurate estimator. Hope that helps! Good luck!


  • Maria Rider commented Aug 10th 2011:

    Haha, I actually found that one. The reference I am using for the protein for lean body mass(which is not the same as total body weight) is on page 192 in the Geek to Freak chapter. 1g of protein per 1 pound of my body weight seems an AWFUL lot of protein. I mean I weight 204.6 lbs....does that mean I have to eat 200g of protein?! That's crazy! That's like five large chicken breasts! I dunno if I would want to tweak the diet to eat even MORE protein. I am already getting results each week, but perhaps my hubby needs more protein cause his results seem to waiver between .5lbs and 2lbs a week. And even though he is 47 yrs old should he be losing more per week? I may try boosting our protein intake A BIT to see if that changes anything. Thanks for the answer!

All Answers


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I don't know about G2F but I've seen many sites and articles using the 1g per 1 pound of your body weight (I've seen em as high as 1.5g per pound and no less than .8g per pound) so it looks like you're both not getting enough protein. (heck, I eat about 100-125g of protein a day and I'm 5'6" 117lb.)

Up the protein and lower the daily caloric intake (with some form of exercise in between) + drink a ton of water = weight and fat loss

That's my formula and I'm sticking to it.

  • Maria Rider commented Aug 10th 2011:

    I would like totally kick myself if boosting our protein was all we needed. Though, I don't have much if any cravings or get hungry too quickly. I guess we'll see if boosting our protein a bit will help. I'll try it next week.

  • yarnphreak commented Aug 10th 2011:

    Gots to watch the calories though. I had the hardest time trying to find lean protein without a ton of calories. (Top 3 I found: lean pork tenderloin, oven roasted turkey breast, tuna-ahi or canned albacore. All have around 120 calories per 4oz serving. Are you surprised that chicken didn't make that list?) Protein and veggies. That's all I seem to eat these days. (I have a small serving of beans for breakfast but that's it)

  • yarnphreak commented Aug 10th 2011:

    Oh, and nuts/seeds in between (don't want to undereat either.)

  • Maria Rider commented Aug 10th 2011:

    I think I may try sneaking in a whole egg on the salads and upping our fish consumption. We've omitted pork from our meals(as one of my tweaks). I'm trying to think of ways to put more protein into the meals we have now without like adding a whole second chicken breast or eating two bowls of chili. :) You are correct in saying I don't wanna bump the calories up....I like it where it is now and I think if I increase the protein in the wrong places it could mean a gain or maintain instead of a loss. I think I am getting enough protein according to the lean body mass, but my hubby isn't. So, I think if I gave him a slightly bigger portion than I would, but boosting both our protein intakes for lunch and dinner, it could help! Thanks for the tips!

  • Maria Rider commented Aug 10th 2011:

    Ok, so I re-read page 191 in G2F chapter....and using the link that Jones posted. I have about 100lbs of lean body mass(so, basically I'm about half fat :P Sad I know) so, I have to consume 125g of protein a day..which is doable for me. My hubby though has less to lose his lean body mass is about 154lbs so about 175g of protein. O_o I am wondering how to get my hubby more protein in his diet without like increasing his calories/fat too much and make him gain.

  • ultraviolet commented Aug 11th 2011:

    I wouldn't put a ton of stock into a calculation of lean body mass based on nothing more than gender, height and weight. When I plug my info into that calculator, I get an estimate that is 25% (almost 40 lbs) lower than the results of a DEXA scan I got a couple of days ago.

  • Maria Rider commented Aug 11th 2011:

    Where can one get a DEXA Scan or Bod Pod thingie done? I'm afraid to find out, but I can suspect I am probably at least 44-51% fat. :P It's just not something you want to see in like black and white(and mostly white!) I wanna know where I can go to get a more accurate reading.

  • yarnphreak commented Aug 11th 2011:

    Bod Pod testing can easily be done at any of nutrition/sports medicine related facilities. But depending on what type of machine (there's a pro version typically in hospitals and a Bod Pod express version that's seen in gyms and such) the accuracy seems skewed. Cost is around $30. DEXA scans can only be done in hospitals via doctor referrals and some don't even check for body comp/fat. just bone density (which is the intended purpose). I've seen quotes of $200-350/scan. Really difficult to find a place that does a full body DEXA scan at an reasonable price without doctor involvement

  • yarnphreak commented Aug 11th 2011:

    That said, here's a post of the DEXA facility I found (the one ultraviolet got her test done at. I'm going in for mine next week)


  • Maria Rider commented Aug 12th 2011:

    Thanks, Yarnphreak! :) I am looking into getting into a Bod Pod I am aware of some sports medicine places...do I need a prescription or can I just go and request one?

  • yarnphreak commented Aug 12th 2011:

    Bod Pod testing can be done without any prescriptions. Just call and make an appt. (oh, and make sure you wear tight fitting clothes. Baggy clothes may yield up to 2% increase in BF result. Yeah, weird) That easy.

  • Minnesota commented Aug 10th 2011:

    I agree with this.


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For determining lean body mass:

You will need an estimated (or ideally, somewhat accurately measured) body fat %. From there, you can determine your lean mass very simply as follows:

[Total weight] x [body fat %] = [weight of fat]

[Total weight] - [weight of fat] = [lean body mass]

Protein consumption:

From there, depending on what school of thought you'd like to use, try to get somewhere between 0.8 - 1.25g protein per lb of [lean body mass]. This will be a fairly large range, and use it as such: if you eat less beans/legumes (such as 1 meal/day instead of 3), then I would suggest sticking towards the 1-1.25 range. If you are more sedentary (depending on the day), then stick to the lower end of your range; conversely if you are more active, such as worked out that day, then go towards the higher end.

  • Maria Rider commented Aug 12th 2011:

    Totally awesome answer, Joshua! Thanks! I think I probably stick to what Tim mentions and go for 1.25 We still eat lentils for breakfast and lunch...but not dinner. I do minimal exercising as does my hubby. So, we'll probably aim for in the middle....like 1g I am seeing if increasing my hubby's protein will help with his weight loss as he's been having rather small losses both in inches and weight. So, I'm willing to try an increase in his protein to see if that is the problem for him. I seem to be doing well enough, but I think I need to up my protein slightly as well. Worse case, it will make us not lose weight or make us gain slightly. But we're trying to keep the protein lean and not very fatty if we can help it so we don't consume more calories.

  • Botticellis Gal commented Apr 20th 2013:

    Hi Joshua..I did my calculations and came up with 76 lbs of body fat! Good grief!! Is that how much weight I need to lose?

  • s joshua commented Apr 22nd 2013:

    botticellis gal: No no no :) If you lost the entirety of your fat mass, that would be bad. There is a minimum amount of body fat that you need to live, and then beyond that, there are various ranges depending on fitness level. This link has a chart breaking down the basics to give you a rough idea of where you should target: http://www.builtlean.com/2010/08/03/ideal-body-fat-percentage-chart... You really just want to find the ideal [target body fat%] for YOU personally based on your fitness goals. To estimate the lbs you want to lose, continuing the calculations above:

    [lean body mass] + ([lean body mass] x [target body fat %]) = [target weight]

    [current weight] - [target weight] = [weight loss goal]

  • s joshua commented Apr 22nd 2013:

    Also its probably good to remind you about the section of 4HB where Tim tested ~7 or so body fat % calculation methods. There was a HUGE range of error depending on the test type, so keep this in mind as well depending on where you are deriving your reading from. The link I posted above also has a link in the first sentence to pictures of men/women at various BF%'s for a rough guide to estimating if that is helpful.

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