Should I use an “Adjusted BodyWeight” to calculate my protein needs?

I have a question about protein recommendations. I am obese, and was told by a dietitian several years ago that I should use my “adjusted weight” to calculate calorie and protein needs. So they’re a lot lower, like a 30 gm difference for protein. Is this right? – Crystal

Great question Crystal, and yes it is more accurate to use an adjusted bodyweight if you are overweight or obese. This is because excess weight which is fat tissue doesn’t have the same calorie and protein requirements as lean tissue.

calculatorTo find your adjusted bodyweight, calculate your “ideal bodyweight” (IBW) first. For women, IBW = 100 lbs for the first 5 feet of height, plus another 5 lbs per inch (so for 5’5″ tall it’s 125 lbs, for 5’6″ it’s 130 lbs, etc.) For men, use 106 lbs for the first 5 feet of height plus 6 lbs per inch above that.

**Note that “ideal bodyweight” is not MY OPINION of what is an optimal body weight, it’s just the calculation we use in medical nutrition therapy. Please don’t send me hate mail anyone – I am not saying YOU need to be that weight.**

To find your adjusted bodyweight, you take your ACTUAL weight minus the IBW (to find out how much extra weight you have) and multiply that by 0.25, then add it back to the IBW. So it’s essentially taking into account one quarter of your extra weight as being metabolically active.

Example: If I were 5’6″ and 240 lbs.

My ideal bodyweight would be 130 lbs, and the difference between by current bodyweight and ideal bodyweight would be 110 lbs. (240 – 130 = 110)

Multiplying that by 0.25, I get that one quarter of my excess weight equals 27.5 lbs. (110 x 0.25 = 27.5 lbs.)

Adding that to my ideal means that my adjusted bodyweight is 157.5 lbs. (130 + 27.5 = 157.5)

So if I were estimating my protein needs, I’d use 157.5 lbs instead of my actual weight of 240.

Hope that helps! Great question and thanks for writing in!

Coach Georgie

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{ 3 comments… add one }

  • Crystal December 13, 2013, 11:51 am

    Thank you again for answering my question and clarifying things!

  • carlos delacruz December 26, 2013, 6:26 am

    Hi Georgie,

    I learned something new, I never heard of this before. I have two questions though: 1) Would the adjusted bodyweight calculation be suitable for people who are working out and are looking to put on muscle? 2) Would you use this formula over simply finding out someones lean body mass and calculating requirements that way? Thank you for the info! -Carlos

  • Georgie December 26, 2013, 11:18 am

    If someone is looking to put on muscle, nothing changes. If they are obese and need to do an adjusted bodyweight though, fat loss should probably be the priority. So if someone is obese but wants to make sure the keep as much muscle as possible and get stronger while losing fat, I would calculate an adjusted bodyweight, then use the adjusted bodyweight to calculate protein needs (1.2-1.8 g/kg) and make sure they are of course, following a good resistance training program. (Many obese people have a lot of muscle already, since moving around a heavier body requires a good amount of strength.)

    Yes, I would use this formula over figuring out someone’s lean body mass.

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