Lean Mass & ALMI
Table of contents
Losing fat is only half the job. The other half is keeping, or ideally building, muscle at the same time. Between my April and October 2026 DEXA scans I managed both overall: about 1.45 kg more lean mass while losing about 7.3 kg of fat. But zoom in by region and there’s a catch. My legs actually lost lean mass.
Snapshot
| April 2026 | October 2026 | Change | Status | |
|---|---|---|---|---|
| Total lean mass | 53.25 kg | 54.69 kg | +1.45 kg | ✅ |
| Lean mass / height² | 18.5 kg/m² | 19.0 kg/m² | ✅ | |
| ALMI (arms + legs lean / height²) | 8.88 kg/m² | 8.89 kg/m² | flat | ⚠️ |
| ALMI percentile (young normal / age-matched) | 48 / 44 | 48 / 44 |
Where the lean mass went
| Region | Lean change, April → October |
|---|---|
| Trunk | +1,697 g |
| Right arm | +272 g |
| Left arm | +149 g |
| Left leg | −131 g |
| Right leg | −344 g |
| Legs combined | −0.48 kg |
| Arms combined | +0.42 kg |
What it is
Lean mass is everything in your body that isn’t fat or bone: mostly muscle, plus organs, skin and water. The DEXA measures it for each region separately.
ALMI (appendicular lean mass index) only counts the lean mass in your arms and legs, divided by height squared. Limb lean mass is almost all skeletal muscle, so ALMI is the number doctors use to track muscle and screen for sarcopenia (age-related muscle loss) later in life. Muscle is one of the best protectors of healthy ageing: it helps blood sugar control, bone strength, balance and independence.
A small caveat: the trunk “lean” figure includes organs and water as well as muscle, so it can move with hydration and gut contents. Some of the trunk gain may be that rather than muscle.
What I’m aiming for
There’s no lab range for this. My own aims:
- Keep total lean mass at least where it is, even as some fat comes back after the competition cut.
- Push ALMI up over time, from around the 45th–50th percentile towards the 60th–75th. For a combat sport athlete in my 30s, more limb muscle is useful both on the mats and for the long run.
- Rebuild the legs specifically.
Was April a problem?
Not a problem, just average. In April my ALMI was in the 48th percentile for young men and the 44th for my age. That’s fine for health, but unremarkable for someone who trains.
Why October is better (overall), and what probably helped
Gaining lean mass while losing a lot of fat is hard, and it’s the best-case result of a cut. What probably helped:
- More protein. I increased my protein intake, which helps the body hold onto muscle in a calorie deficit.
- Training volume. BJJ at New Era MMA went from once a week up to 6 times a week for my competition on 11 October, and from early September I added a full-body conditioning programme (squats, pushes, pulls and core, 2–3 sessions a week).
- Grappling is upper-body heavy. Gripping, framing and pulling work the trunk and arms constantly, which probably explains why most of the gain was there.
Why the legs went backwards
My legs lost about 0.48 kg of lean mass. ALMI only stayed flat because the arms gained about the same amount. Probably reasons:
- A knee strain. I strained the back of my knee doing kettlebell swings at the start of September, which cut into lower-body strength work.
- A neck injury. In early October I was diagnosed with disc herniations in my neck, and I was told to ease off training. That made heavy loaded exercises like squats a no-go for a while. (The full story is in the ALT article: ALT Deep Dive: Etoricoxib and My Neck.)
- The cut itself. In a big calorie deficit it’s easy to lose some muscle in areas you’re not training hard.
What’s next
- Bring lower-body strength work back as the knee and neck allow.
- Upper-body training is limited for now. My right elbow was hyperextended in an armbar at the competition, and I’m out of training from 11 October until 20 November. So the next few weeks are rehab and whatever leg work is safe.
- Recheck at the next DEXA. The goal is for leg lean mass to recover and ALMI to start rising.
This is my own personal data, shared for interest only. It’s not medical advice.
Until next time, peace and love!