Methodology
Protein Per Kg of Lean Mass vs Bodyweight, a Worked Example
Francesco Zen, founder of ZTraining · Last updated June 19, 2026
| Scenario | Lean-mass based | Bodyweight based | Gap |
|---|---|---|---|
| 200lbs, 15% body fat | 170g | 200g | 30g |
| 300lbs, 30% body fat | 210g | 300g | 90g |
Why a 30g gap matters more than it sounds
At the smaller end, the difference looks minor on paper. In practice, that extra 30g is a meaningful digestive load for no real benefit, since lean tissue is what actually uses the protein, not body fat.
Why the error keeps growing
As body fat percentage rises, the gap between bodyweight and lean mass widens, and so does the error in a bodyweight-based calculation. At 30% body fat, a third of total weight isn't tissue that needs protein at all, yet a bodyweight formula still counts it. The higher the body fat, the worse a bodyweight-based number gets.
Related: How much protein to build muscle · Body-fat threshold rules for building muscle
Francesco Zen is the founder of ZTraining and ZLIFE, with 18 years of coaching experience working with executives across the UK, US, and UAE. He built Mr Z, an AI coach trained on his methodology to bring the same approach to a wider audience.