Ratio of fat mass vs. lean mass when losing fat

[Dominique]

For the past six months, I’ve been dieting for fat loss. I have a longer post about it in the weight loss forum, but here are the key numbers:

starting weight: 66.6 kg (BMI: 22.0), body fat: 17.8%

current weight: 63.0 kg (BMI: 20.8), body fat: 15.5%

average daily expenditure (as per Fitbit Surge): 2986 calories

average daily deficit: 167 calories

average daily protein intake: 110 grams (1.65 g per kg / 0.75 g per lb of body weight)

resistance training: 5 sessions of 50 minutes every week

average daily step count: 17k

Now my 3.6 kg weight loss was 58% fat mass (2.1 kg) and 42% lean mass (1.5 kg). Is this a usual ratio? As far as I can tell, I’ve been doing all the right things for minimizing muscle loss: very moderate deficit, high protein intake, resistance training. I’ve also been eating a decent amount of food (2800 calories) for a guy my size and my age. I would have loved to see "minimizing muscle loss" mean 90% fat mass / 10% lean mass. Is this simply unrealistic? 

[FitBeforeFifty]

The general expectation is 75% fat and 25% fat free mass loss. This meta-study attempts to determine if the "Quarter FFM Rule" is in fact a good approximation. The conclusion is "it depends"  but overall I think the expectation of losing 25% or less is a reasonable expectation based on the studies I've read -- especially when you include resistance training.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3970209/

Personally, I wouldn't worry about it too much if you are following what everyone would consider the correct protocol.

Also keep in mind your method of measuring fat free mass is via a consumer grade device with unknown accuracy. Have you lost strength during this time period ?

[A_Lurker]

You mention resistance training, but I have some questions about that.  Are you lifting higher or lower reps?  12-15 being higher, 5-8 being lower.  Your post pointed me back to Lyle McDonald's site the other day, and I think you're familiar with some of his work.  He talks about the differences between the two here:

http://www.bodyrecomposition.com/training/weight-training-for-fat-loss-part-1.html/

The bodybuilder I used to work with years ago (wow, more than a decade now) would lift very heavy during maintenance weeks (usually 2) then lift close to what he had been lifting during dieting weeks (usually 4).  He would do personal best one-reps during maintenance, but was increasing them every time.

[JohnRi]

I'm no where near your fitness level ...  YET... 

My stats via Trendweight...

Current fat % 25.6

Current fat mass 53.2 lbs

Current lean mass 154.4 lbs

Fat % drop since I got my Aria in February 9.3 %

Fat mass drop since I got my Aria in Februrary 34.1 lbs

Lean mass drop since I got my Aria in February 8.5 lbs. 

My estimate fat % when I started 45%.

I have been able to maintain around 155 lean mass for since March.  It's been higher and lower.  But I've managed to keep it more or less the same.

Up until recently, I haven't had to make any adjustments to my diet.  However I'm increasing my intake twice now, and probalby going to up it a little more again.  Every time I see my fat % go up, lean mass go down, I've been able to stop it so far, by adding calories to my diet.  I have no idea if I'll be able to do this as I lose more weight.  I know based on my weight training, that I'm putting on muscle mass.  Arms are bigger, stronger, and shirts sleaves are getting tighter.

I do know that if I manage to keep my lean mass around 155, if I can get to 170 lbs, I'll have a fat % around 10.  Which as you know, is impossibly low.  So I'm expecting a lean mass loss, or a weight loss plateau that I can't break. 

All I know is I can't wait to see what happens.  This is fascinating...

[Dominique]

@FitBeforeFifty: thanks for pointing me to the study. Yes, I’m aware of the limitations of the device used for estimating BF. I’m not overly worried about my findings, especially since I wouldn’t know what else I could have done in order to achieve better results. As to strength, I’ve actually seen a slight increase, probably because I’m still in the "newbie gains" territory.

@A_Lurker: I switched to a new resistance training programme when I started this fat loss phase. It’s based on daily undulating periodization (DUP), which means I’ve been doing the same basic exercises (bench press, deadlift etc.) several times a week in all rep ranges. I’ve quite enjoyed it, because of the variety.  

@JohnRi: your ratio would have been 80% fat mass / 20% lean mass, which is even better than the "Quarter FFM Rule" mentioned by @FitBeforeFifty. Kudos for that! It intuitively makes sense that if you start with a higher relative fat mass, it would contribute more to the total fat loss.