Do you ever wonder how much protein you should be eating?

Getting enough protein helps you maintain your muscle mass and bone density, both of which tend to decline as we age. And this loss of muscle and bone leads to loss of ability to do stuff, which is a key factor in aging – feeling un-able is a big part of what makes us feel older.

Now, unlike with carbs, our bodies do a pretty good job of telling us when we need more protein, and when we’ve had enough. So if you are craving protein, in most cases, you should eat more protein! And if you don’t want any more, you probably don’t need to eat any more.

However, sometimes it’s helpful – or maybe just interesting – to see how your consumption compares to what’s recommended.

One of the ways to calculate protein needs is to estimate your lean body mass (LBM).

LBM is the amount of your body weight that is everything but fat – muscles and bones and tendons and blood and water and all the rest of the stuff that make up you.

So, the first thing to do in calculating your LBM is to estimate your body fat percentage (BF%). If you have a scale that does this for you, great, use that number. If you don’t have one of those, refer to this series of images to estimate which fat percentage bracket you think you are in. This won’t be precise, obviously, but that’s ok.

body-fat-percentage-women-and-men

Visual estimate of body fat percentages for women and men

Now take that BF% number, and multiply your total body weight by that percentage.

So let’s say you weigh 160 pounds, and you estimate that you have 40% body fat.

160 x 40% = 60 pounds of body fat

160 pounds (total body weight) – 60 pounds (fat) = 100 pounds LBM

Now, to check this number another way, let’s roughly estimate your ideal body weight (IBW):

For women, start with 100 pounds, and for men, start with 110. Add 5 pounds for each inch of height above 5 feet, or subtract 2 pounds for each inch under 5 feet.

Now adjust for body frame size: circle your thumb and middle finger around your wrist. If your fingers just touch, you have a medium frame, and the calculated weight is correct for you. If your fingers can’t touch, you have a large frame – add 10%. If they overlap, you have a small frame – subtract 10%.

So, let’s assume a woman with a medium frame and a height of  5’5″:

IBW @ 5’5″ medium frame = 100 + (5″ x 5) = 125 pounds

Ideal body fat for healthy, fit women (not extreme athletes) is between 21-24%, so let’s say we’re aiming for 23%.

125 pounds x 23% = 29 pounds of body fat

126 total pounds – 29 pounds body fat = 96 pounds LBM

So our earlier calculation of 100 pounds LBM was pretty similar.

With LBM estimated, we can now determine protein needs. For a sedentary to moderately active person (1), 1g per kg of LBM is considered by many to be optimal and is what I recommend for most of my patients. For an active (2) to very active (3) person, 1.25 to 1.5g per kg of LBM is recommended. Convert your LBM to kilograms by dividing by 2.2, and then multiply using the appropriate activity level factor:

(1) 100 # LBM / 2.2 = 45 kg x 1g = 45 grams of protein daily

(2) 100 # LBM / 2.2 = 45 kg x 1.25g = 56 grams of protein daily

(3) 100 # LBM / 2.2 = 45 kg x 1.5g = 68 grams of protein daily

To get an idea of what that looks like on your plate, here are a few protein sources with their protein content:

  • 1 egg                                  6g
  • chicken drumstick       13g
  • 4 oz hamburger             16g
  • 3 oz chicken thigh        21g
  • 3 oz  fish                          22g
  • 5 oz pork chop               41g
  • 6 oz steak                        52g

Happy eating!