Lost 19 lbs but DEXA fat barely changed?

2026-09-24 12913 views 65 posts

I'm 5'6", started at 188 lb in January, now 169 after 14 weeks. The scale has bounced between 171 and 169 for 18 days.

I lift 3x/week, walk 8k steps, eat 1600-1800 cal with 120g protein. Got a DEXA: fat mass went 74.1 to 71.8 lb, lean 108.2 to 106.9.

That's only about 2.3 lb fat gone from a 19 lb scale drop. Did I mostly lose water/glycogen, or is the scan just noisy? Anyone seen this?

DEXA can swing a few pounds of lean just from hydration and glycogen. 19 lb scale drop in 14 weeks is still solid.

Agree. My DEXA after a salty weekend showed +3 lb lean and I changed nothing. It's noisy.

Mine had me fast 8 hrs, no workout 24 hrs, same clothes. Without that I wouldn't compare scans.

If you lost 19 lb but DEXA fat only dropped 2.3 lb, something's off in the math or the scans. DEXA has ±2-3% body fat error, and lean loss can be glycogen/water. Were both scans on the same machine and software? If not, I'd trust waist and strength trend more than one follow-up.

At 1600-1800 and 120g protein, you're probably not losing much muscle unless the deficit is huge. The 18-day stall also screams water retention from lifting or salt. I'd compare waist, pics, and lift numbers before changing anything.

The 18-day stall and DEXA oddity might just be water masking fat loss. Are your lifts holding?

My lifts tanked when I cut too hard.

That's the clue. If strength is stable, lean loss is probably measurement noise.

Did you use same hydration? I chugged water before my first scan and it skewed lean up.

Not OP, but I had a similar 20 lb drop where DEXA fat was only -5 lb. Turned out my first scan was after a carb-heavy weekend. Second was fasted. Waist was down 3 inches though, so I stopped stressing over DEXA. Track trend every 3-4 months, not monthly.

What do you rprogress pics and waist tape say? Those beat one DEXA for me.

I'd also look at the actual fat mass numbers: 74.1 to 71.8 is only 2.3 lb, but if lean went 108.2 to 106.9 that's 1.3 lb. That's 3.6 lb of the 19 lb loss. The rest was likely water/glycogen/food weight. Still a real loss, just not all fat. Give it another 6 weeks and rescan under same conditions.

I paid for two DEXAs six weeks apart and the fat number moved 4.1 lb while my scale moved 0.8, because the first one was after a Friday pizza-and-beer night and the second was fasted and dehydrated. For your 14-week gap, scan conditions alone can swing 2-4 lb of fat/lean.

Were both scans same time of day, fasted, no hard lifting for 24-48h, and similar hydration? That’s the first thing I’d check before assuming the scale lied.

Tape measure and how my jeans fit told me more than my one DEXA ever did.

I’d audit weekends before blaming the DEXA. My 19-day stall broke when I actually logged Friday nght through Sunday instead of calling it 'maintenance': it was 800–1200 extra per day, which erased about 4–5 lb of monthly fat loss on paper.

Weighing food for two weeks showed my '1600' was closer to 2050 on Sat/Sun. Do you track the same way on weekends as weekdays?

The scale says 19 down. Your knees, sleep, and blood pressure probably noticed even if DEXA didn’t.

DEXA can swing a couple pounds just from hydration and sodium the day before. Did you scan fasted or after a salty meal?

My first scan said 31.8% fat, repeat 11 days later said 29.9% at basically the same scale weight. Same machine, different tech, I'd had a heavy leg day before the first one. Now I book mornings, fasted, no workout 24h prior, normal water. I'd trust the trend across two scans more than one.

I had the opposite pattern: first 10 weeks scale dropped 16 lb, DEXA fat only down 3.8, then next 9 weeks scale sat within 2 lb while fat dropped another 6.1. The early drop was a ton of inflammation/water from a bad flare and way more carbs than I thought.

The later recomp showed up in my squat going from 95x5 to 135x5 and resting heart rate falling 9 bpm. So one scan 14 weeks in can be a mid-roll snapshot. Did your main lifts hold or go up? If yes, I wouldn't panic about the lean number yet.

A 19 lb drop with only 2 lb fat usually means a lot of water, glycogen, and gut contents were in that starting number.