Can you lose both muscle and fat while building FTP? Or is my scale useless?

I have been weighing in daily with a Weight Gurus scale that reads body fat and muscle percentage. After 4 month hiatus off the bike, I have built up my FTP from about 210 in January to 265 as of a month ago. I’ve also lost 14 lbs in the process. However, in January I weighed 203 and had a muscle reading of 41.7% - which I believe indicates 84.65 lbs of muscle. Today I weighed in at 189 with a muscle reading of 43.1% - or 81.46 lbs of muscle. Body fat percentage is down from 18.6% to 16%.

Before I chuck this scale, I thought I’d check if this is even possible? Can you lose both muscle and fat while building FTP? I am not doing any calorie counting or restrictive eating. I follow each workout with a recovery shake, eat pretty carb-centered and don’t skimp on the protein. My rides are 120 minutes or less. I just don’t see how this scale could be telling me the truth.

PS. I’m in my second month of using TrainerRoad and I love it.

It’s basically impossible to lose weight and have lost weight be 100% fat. Look at this way, a greater percentage of your body weight is muscle compared to where you started. You’re headed in the right direction.


I had a very similar experience; losing about 20 lbs from 6/5/18 thru 10/27/18. My total body weight went from 203.3 down to 183.3, with lean muscle mass going from 155.5 to 150.2, and body fat percentage/pounds from 19.5%/39.6 to 13.7%/25.1. Since that low weight, I have put some weight back on and now sit at 191.1, 153.8. and 15.3%/29.1 respectively. I’ve also put on ~60w going from low FTP of 241 (late-July) to 302 (today). In early-June '18, my FTP was ~270 but dropped off quickly through the summer and after some time off the bike.

I use the Tanita RD-901 Plus scale, and actually track my metrics manually on a 7d average basis, always weighing myself 1st thing in the morning. What I’ve noticed with the weight gain off the lows is that it my lean mass/total body weight percentage is slightly better than it was on my way down, indicating muscle gain has slightly outpaced the fat gain over that time frame.

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The opposite of this is also true. You can sit in front of the TV for a few weeks pounding Ben & Jerries and you will gain lean muscle (along with a lot of fat).

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It’s definitely possible to do this, in fact quite normal. I don’t know that I would put too much trust in the overall number given by scales for muscle, fat and water weight. Tracking weight trends over time is probably reliable. Even that can lead to some bad behaviors if you have a habit of looking at the numbers too often. I think has an excellent method of weight tracking on an exponentially smoother weighted 20 day day moving average based on the Hackers Diet. Fat percentage trends are ok, but I think the mirror is more accurate.


Is this true or am I being naive? :slight_smile:

It’s true

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Increases in FTP are rarely ever due to an increase in muscle mass so its very easy to lose muscle and fat while gaining fitness. I pretty much do it every spring as ride durations increases 3-4x.