Adopt-a-noob:Cindyinpg + Fiorella135

Cindyinpg

Fiorella and I are currently discussing how to calculate your lbm so that you can most accurately set your macro goals.

Cindyinpg

From: http://www.myfitnesspal.com/topics/show/819055-setting-your-calorie-and-macro-targets

1g of protein per lb of LBM as a minimum target

0.35g of fat per lb of total body weight as a minimum target

The balance can fall where you wish, taking into account performance, satiety and adherence.

When you have determined the minimum grams of protein and fat, you can calculate the corresponding percentages based on your calorie target to input into MFP. Protein and carbs have 4 calories per gram and fat has 9 calories per gram. Note that MFP only allows 5% increments so you will need to pick the one nearest your desired target.

For example, say someone is 150 lbs with a BF% of 20% on a 2,000 calorie target. Note, a 20% body fat means that someone has a 80% lean body mass (LBM) as LBM is everything except fat (muscle, water, organs, tissue, etc). Their macros in grams would be:

Protein: 1 x 150 x 0.8 (LBM) = 120g x 4 calories = 480 calories divided by 2,000 (calorie target) = 24% - round up to 25%
Fat: 0.35 x 150 = 53.5g x 9 calories = 473 calories divided by 2,000 = 24% - round up to 25%

So using this calculation for myself I cheat and get my lbm from an online calculator and get 120-130. I am 5"11 175-180lbs.

So my protein target is like the example 120 or a tad higher for 480-500ish. Also like the example, I usually gross about 2,000 calories, so I am okay with my protein at 25%.
My fat target is .35 x 175 = 61.25 x 9 equals 551, so, 550 divide by 2,000 is 27.5 so I can round down to 25 or up to 30.

So, again like the example, I end up with 50/25/25

Other mentors on here may have more to add on this discussion. Certainly there must be better ways to calculate lean body mass, but I am happy with estimates for myself.