Finding Optimal Performance Weight with Body Fat Percent by Matt Fitzgerald

At 54 I’m the fattest and heaviest I’ve ever been while riding/racing bikes. I’m 5’10"/178cm and I wanted to figure out an optimal performance weight (as stated in Matt Fitsgerald’s book) so I bought a Tanita body fat scale. Right now it says I’m at 15.5% and 175lbs. My goal is 10% which works out to be around 164lbs. That seems heavy to me but, I’m new at all things calculating optimum weight.

Curious where you guys are and where you want to be? I’m more curious with the older crowd but you 40 something and younger whipper snappers are welcome to chime in and bum us older guys out!


You never said how tall you are.

height and your build, at 185+cm I haven’t seen 164 since 10th grade and that was 44 years ago LOL.



Yes I’ve always been “stocky” and as far as cycling more a track/sprinter build. With that said, 10 years ago I was as low as 147 (not sustainable) and felt really good at 155-160. 10 years makes a huge difference when talking 45 to 55 to 65…not so much the other way IME.

That seems like a healthy weight goal?! The 24 year old LBS manager is claiming 150 but I think having seen him lift heavy in the off-season and push 170, I think he is closer to 155-160 right now.

I’m shooting for 185-190 and now in sixties am unwilling to give up great food and upper body muscle to go lower. Because I don’t think its going to deliver a big change in performance at this point, I’m fighting to not lose muscle and aerobic top-end.


At age 54 you want to go down to 10 %? That sounds like an arbitrary number to me, and one that is hard to attain even when men are in their physical prime. E. g. according to this chart, then 10 % is below what is considered healthy in your age bracket.

And it seems that you’d have to approach this arbitrary goal from the weight lifting and body building end, something that would invariably make you a weaker cyclist. 15.5 % at your age is perfectly healthy, and you are still in the fitness category. People’s body fat percentage naturally tends to increase with age, so your numbers are IMHO still very, very good.


It’s from a chart in Matt Fitsgeralds book taken with permission from data compiled by Kip Russo. I picked 10% after I figured out different % and the weights they yielded. Given I’ve been stable until recently at 165 it seemed logical. Now whether the scale is accurate or not is another issue. I picked Tanita as they have good reviews and suggested by Fitzgerald…

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Even with this explanation, I think the number seems arbitrary.
Let me just go by what I see: you have highlighted 11.4 % in the 40–49 age bracket, which is not only higher than your goal, but also in the wrong age bracket. The corresponding number in your age bracket is 12.9 %, let’s call it 13 %. Your goal is 3 % below that. These rows denote the 95th percentile, i. e. the number hit only by 5 % or less of the population (I don’t know whether this data is taken from a cross section of the entire male population or a subset).

According to these numbers you would like to belong to the top-2 % in terms of body fat in your age bracket (I’m interpolating between 12.9 % and 8.8 %) when you are currently in the top-10 %. Do you realize how difficult this will be?

Moreover, you seem to think that lower body fat percentage = better, which is decidedly not true once you get to the low end. If you want to enter into these extreme body fat percentage ranges, it is very likely that your training on the bike will be impacted. It will be much harder to nail your nutrition, e. g. to make sure that your calorie deficit doesn’t have a negative impact on your training and prevent your body from turn to your muscle tissue for nourishment. The closer you get to super low numbers, the more you have to nail everything. And you still might get slower on the bike in the process.

In 2019, I was between 12–13 % body fat, 71.5 kg and put out 4.3 W/kg (FTP of 311 W). Last season I weighed around 73 kg at my peak had about 15.5 % body fat and put out 4.7 W/kg (max FTP of 342 W). (I made a conscious effort of gaining a little weight since people with low body fat percentage are more prone to getting sick, not something I wanted to risk during a pandemic.) Yes, it is always tempting to think “Yes, but what if you put out those numbers at 71.5 kg? Or better yet, 70 kg?” Did these thoughts cross my mind? Sure. But the thing is that these are not independent knobs you can twist at will.

I would rethink the strategy and start from cycling performance, not body fat percentage. Your body will find the optimum here by itself. Given your age, though, I think you should be clear about your expectations: even with optimal training, you should expect a slow decline. Also, I would shift my effort from just cycling and put more emphasis on general health such as a strong core, arms and shoulders to prevent e. g. back problems and the like. Pay attention to your joints and tendons. Just from that you might lose some performance since you are carrying around (muscle) weight on your upper body that isn’t necessarily contributing to making you faster in the narrow sense. But it will make you faster in the long run.


I’m 6’ (183cm) and 158lbs (71.7kg). I find it pretty unlikely that I am less than 10% body fat.

The sad reality that anyone who has dieted down to 10% or lower will tell you is that you’re going to be wayyyy lighter than you expect.

I was 147 at 6’ tall the first time. That was 10 years ago and now 158ish at the same waist measurement as then.

You will also look way more jacked than your weight tells when you get that lean so don’t get fixated on the weight, instead track your waist measurement at your bellybutton.

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Thanks for your thoughts Oreo! I do appreciate it. I don’t disagree with most of what you wrote. Believe me I’ve been at this longer than most. TBC The highlighted was me when I was 40-49 years old. It has nothing to do with where I am now. The book has been collecting dust for years on a shelf. Just saw it before I went to work the other day and found this section of the book interesting.

How old are you Oreo?

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Yeah I think the 10% weight I came up with via Matt’s method seems way way way way heavy. Part of why I posted.

Anyways, 165 for me used to be everyday all day 50 yo weight. 160 would be good. 155 would be veins everywhere. Thinking 160+/- is more optimum.

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Also @ebikas +1 on the waist comment. That and just looking in the mirror have been the best (for me) detect change. Weight is sort of secondary. Everything with weight and fat gets sort of taken out of context.


Super agree!

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I’m 41.

Ah, ok, thanks for the context. Still, pursuing 10 % seems like a tall order fraught with potential problems.

I do sympathize, also I want to lower my weight a little, but I’m aiming for something more modest, 72–73 kg, i. e. as it stands now, I’d need to lose about 1.5–2 kg. I’ll probably do that towards the end of this season since I don’t want to disrupt my training too much. I’d really kick myself in the rear-end if losing weight came at losing power or a disruption in my training.

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47 years old, 185cm around 76kg , waist circumference 78cm. I want to lose 1cm around my waist and gain 2kg of muscle.

Your bmi is 24.9 so unless you are very very muscular you have some room to lose weight, you could even go down 72 kg and still be well within the healthy bmi range. I wouldn’t trust the body
fat% on those scales, I have an omron and the body fat and muscle % fluctuate wildly like 6% over a day

I also don’t think you need to get fatter as you get older, that table is just what your peers are doing, you can be as healthy with low fat as someone who’s 25



Are you using the athlete setting or regular setting? I don’t have a Tanita but a friend I occasionally stay with has the one with the handle that does segmented body composition analysis, I’ve used it a few times recently and athlete setting seems to return about a 4% lower BF measurement on any given day. 8-10% vs 12-14% for me. According to the blurb I should use athlete setting (been training >10 hours/week for a long time and resting HR in the 40s) but I’ve got to say the higher numbers seem more likely to me.

It’s pretty much impossible to only lose fat, however careful you are with protein intake, keeping a small calorie deficit, etc you’ll lose a bit of muscle mass along the way so realistically getting to 10% BF is likely to take you down to 160 or lower, not 164.

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I don’t get hung up on numbers as the different ways of measuring bodyfat give varied results. I’m about 61 - 62kg and 1m70cm. my mates think I’m skinny and this has been constant since 2007. I have run a 2:47 marathon/1:17 half marathon in the past and last year managed a 53min 25 and 20min 10 mile TT…I was 54 last week. Train hard, eat a reasonable diet and have a few beers if that’s your thing (it’s certainly mine) and you’ll be fine. With the current state of the world there are more important things to worry about than precise body fat :grinning: