Optimal Fat Loss Or Optimal Physical Performance? You MUST Pick One

Optimal Fat Loss Or Optimal Physical Performance? You MUST Pick One

One of the worst things you can do during a fat loss phase is train for a big performance goal such as a marathon.

Ivan Gavranic Ivan Gavranic · Jun 23rd, 2022

Mindset Intermediate
19 Mins


    The Reality Of Losing Fat

    I have spoken about the misconceptions regarding exercise during a fat loss phase in previous articles that you can find here, here and here

    To summarise, you just don’t need to be doing a lot of exercise to get your desired fat loss result. Weight training 3-4 times a week with an emphasis on progressive overload with 10-15k steps per day will be enough for many people to make tremendous progress just as long as they nail their nutrition (the most important factor).

    For some, we like to add in some low intensity cardio (1-2 x 30 minute sessions at a pace you can hold comfortably) due to the health promoting aspects more than anything but even if we are really pushing the envelope, the less activity an individual needs to do, the better.

    This may sound counterintuitive as more exercise is better, right? More is better when you have the resources (calories) to adapt to that training but when you’re in an energy deficit while also trying to hold onto your muscle mass, the best thing you can do is focus on your resistance training as you can only adapt to so much.

    By doing a lot of additional cardiovascular work, you impose a larger recovery demand on your body that will only lead to excessive fatigue, especially on the central nervous system which is directly responsible for how much force your muscles can produce. 

    Research shows that very high rep (over 100) training and moderate, long duration cardiovascular training is more fatiguing to the central nervous system than traditional strength training. 

    A big part of this is down to the fact that endurance training done with a moderate to high intensity utilises a high amount of carbohydrates, leading to a large reduction in glycogen stores. 

    Just by being in a calorie deficit, your glycogen stores are already going to be somewhat depleted most of the time and it’s well documented that when these levels drop below a certain threshold, performance and your overall energy levels take a huge hit.

    “Furthermore, it has been well documented that the capability of skeletal muscle to exercise is impaired when the glycogen store is reduced to a certain level, even when there is sufficient amount of other fuels available. Together, prolonged endurance exercise leads to muscle glycogen depletion, which is in turn linked to fatigue and makes it difficult to meet the energetic requirements of training and competition.”

    Put simply, by trying to do a lot of productive cardiovascular exercise with relatively little energy coming in, you’re going to cause excessive fatigue without reaping the fitness benefits.

    And yes, the same can be said for overweight individuals. Just because they have a lot of stored energy to tap into, does not mean they can readily access it as easily as someone who is very lean. Remember, being overweight impairs your ability to use fat for fuel along with being able to expend a lot of energy through activity.

    This segues nicely into the crux of what we are going to be talking about today!

    Why Fat Loss First Should Be The Approach For Most People

    When you look at the yearly plan for any team sport, the majority of the intentional body composition changes take place during the first 3-4 months of their pre season. 

    For example, if we take a rugby team that requires different approaches to each player, it’s not uncommon to see some of the heavier forwards undertake a calorie deficit to get them back into their ideal body fat percentage before the season starts. During this period, the player will more than likely have a low energy availability score (discussed in detail in the next section) meaning his performance capacity is not going to be high. 

    Rugby is an extremely demanding sport that requires a high level of aerobic capacity, explosiveness, sprint repeatability all while taking collisions. Trying to improve all of these aspects while being in an energy deficit will not only lead to subpar results, but a higher risk of injury, falling sick and not being able to do as much work.

    Now, I understand that the probability of YOU being an elite level rugby player is not very large so how does this information apply to you? 

    Well, if you have big performance goals such as wanting to run a marathon, partake in a century ride, add 100kg to your squat, get a black belt in jiu jitsu or anything that you want to get really good at, this exact principle of “getting in shape first” stills holds true. 

    Energy Availability (EA)

    I have briefly mentioned the concept of energy availability in this article but put simply, it is the dietary energy ‘available’ for normal metabolic processes after the expenditure of formal exercise has been accounted for. 

    We then take the above number and divide it by an individual's lean body mass which gives us a strong indicator of the relationship between energy expenditure and intake. 

    (Energy intake - energy expenditure from exercise) / Lean Body Mass (LBM) = Energy Availability (EA)

    Let’s look at an example below.


    • 70kg male with 60kg of lean mass (14% body fat).
    • Consuming 2500 calories
    • Expending 600 calories through activity each day on average.


    • 2500 - 600 = 1500
    • 1500/60 (LBM) = 25


    • 25
    For optimal performance, an EA of 40-45 appears to be the “sweet spot” for many athletes to be getting the most out of their training and recovery. When an athlete starts getting below 30 and staying there for chronic periods of time, not only do they see performance decrements but their health starts to deteriorate too. 

    If we take the above example, it would be safe to assume that the individual is in a state of “low energy availability” meaning he isn’t going to be in the best place to really maximise their performance.

    Can he continue losing body fat? Certainly! But by making that his number 1 focus, he cannot expect to reap the same performance benefits from all of his training especially if he's going from 14% down to 10% body fat.

    Energy availability is largely influenced by lean body mass and total fat mass which is why people who are already very lean are far more susceptible to running into issues if they are not careful. 

    I’m Not An Athlete Or Very Lean, Why Are You Telling Me This?

    Good question. A lot of the research on energy availability is on athletes who are usually already lean and conditioned for their sport but even still, we can extrapolate this information and apply it to our own journey.

    As a byproduct of wanting to lose body fat, we are automatically going to be inducing a state of low energy availability. To lose body fat, we must be expending more energy than we are consuming, meaning if we were to be eating at an “optimal EA” then no weight loss would occur.

    So if we KNOW we are already going to be in this state, why the heck would we drive ourselves deeper into this state if we don’t need to? I have spoken about the limitations of exercise for weight loss in previous articles that you can find here and here but the same idea can also be applied to performance.

    If you want to seriously train for a marathon, being in a state of low energy availability is only going to hinder your performance, recovery and overall health. 

    RNT member and overall beast Ian Bower did manage to continue training a lot while also dropping body fat but he was already a very conditioned runner prior to joining. He simply needed more guidance on nutrition and up to a point, he was able to make decent progress but it’s safe to say that if he focused on losing body fat first while keeping his running at a more ‘maintenance’ level, his performance could have been even greater. 

    Why? Because he would be lean, healthy and have a lot more fuel coming in meaning he can tolerate and recover from more.

    OK, That Makes Sense. But What If I Really Enjoy Those Activities?

    If you truly enjoy these activities, there is no issue with incorporating them into your plan with the caveat of NOT pushing the envelope. 

    Continuing with the marathon example, adding in 1-2 low intensity, slow jogs per week with a capped time (say 45 minutes each at a pace that you can comfortably hold for 1 hour+) can still improve your aerobic capacity to some degree without taking a toll on your recovery. My recommendation for tracking progress here would be to monitor your distance and rate of perceived exertion. The goal should be to slowly start covering more distance without increasing your effort levels. 

    By aiming for distance alone, you will find yourself trying to push harder and harder which is not the goal right now. Save this for when you are in your investment phase!

    A common mistake we see is when individuals are given a generic running program (or found one online) that doesn’t take into account all the other activities they are doing. Combining resistance training and cardiovascular training is a fine balancing act and as previously mentioned, if the goal is fat loss you need to be prioritising resistance training and nutrition. 

    Is There A Way To Do Both?

    Yes and no. Mostly no.

    Theoretically there are ways that you can set up your nutrition and training to chase both performance and fat loss but it can be very difficult from a practical perspective. 

    Firstly, you would already need a solid understanding of the foundations when it comes to nutrition along with having a good relationship with food and exercise. Adherence shouldn’t even be an issue at this point, you have good sleep hygiene and your overall life stress is very manageable.

    This already rules out 99% of the people we work with but let’s say you are in that 1%, the below is how you could still improve your performance substantially while also dropping body fat.

    Starting Information

    Timeframe: 30 Weeks

    Starting Weight- 80kg @25% body fat (60kg LBM)
    Target Weight- 65kg @10% body fat (58.5 LBM)

    Running Experience- Minimal and inconsistent.
    Running Goal- Run 10km in under 55 minutes

    Resistance Training - 3 x Full Body Sessions/Week (will stay consistent)

    Running- 1 x 45-60 minute slow run, 1 x interval session (4 x 4 minutes at an 8RPE- 6 minutes of rest between intervals).

    Over time, an additional long run will be added while slowly increasing the duration closer to 90 minutes.

    We will maintain 1 interval session per week but manipulate the intensity as time goes on.


    If we break this goals down, these would be the main outcome metrics we would be measuring:
    • 0.5kg loss per week on average.
    • Gym progression to maintain and/or gain lean body mass.
    • Running times, total distance covered, heart rate and RPE with each session.
    Note how the rate of loss is ~0.6-0.75% of BW per week. A slower approach in this case will help maintain performance and lean body mass.

    We know that what matters most for fat loss is your weekly energy deficit meaning that calorie cycling (having high and low days) would be a very good strategy to:
    1. Increase energy and carbohydrate intake on higher energy expenditure days.
    2. Drive calories down on rest days to promote fat loss.
    With this approach, we can acutely raise energy intake to accommodate the extra activity and vice versa. 

    It’s also important to note that even though this is a better way to chase both, there will come a point where recovery and adaptation will still not be optimal. At the end of the day, the overall energy balance is still being tipped towards a deficit. 

    At 80kg with all the additional activity he is doing, his total energy intake needs to average out to be ~2300 per day (16,100 across the week) to get the desired rate of loss. This would put him at a net 10% energy deficit overall.

    With a calorie cycling approach, let’s see how a typical week could look like. Also, the energy expenditure are rough estimates based on his body weight, duration of activity and intensity.
    Even though this approach may offer some benefits to increased performance, the overall complexity and additional stress that comes with planning is just not worth it. 

    For example, tracking your daily weight can be a nightmare to get a running average as the varying amount of food from day to day in and of itself will cause a lot of fluctuation. Also, if you see your performance dropping but the weight is coming down, is a change warranted or is that drop in performance a result of you dropping weight? If performance was good but no weight loss occurred, what then?

    As you can probably tell, things get way too murky and overly complicated which is why I personally would not advise such an approach. 

    The above is a perfect example of how theory doesn’t always translate in the real world and why the most practical approach is to go all in on either fat loss or performance, NOT both at the same time.

    So Are You Saying I Shouldn’t Focus On Anything Else But Weight Loss?

    Absolutely not! We are massive advocates of using other goals to keep motivation levels and enthusiasm nice and high during a fat loss phase. 

    The below are some great goals to focus on that can be achieved without running into any issues.
    • Aiming for a pull up and/or more repetitions.
    • Getting stronger in your indicator lifts week on week.
    • Getting more active with steps.
    • Performing with more focus and intent at your job.
    • Waking up refreshed consistently.
    • Getting better in the kitchen.
    • Becoming more nutritionally literate.
    • Working on your stress management techniques.
    • Get better at eating out.
    As you can see, there is a lot you can work on during a fat loss phase that will all indirectly impact your results without causing you to use up a lot of excess energy. Granted, some of the above can be cognitively draining but they will never impact your recovery to the same degree as a ton of extra activity would.

    In Summary 

    Achieving a body transformation is no small feat and is not the same as “just dropping a couple of pounds” which is why we recommend going ALL IN while saving your other big goals for the investment phase where you are in the shape of your life and have the capacity to not only do more but most importantly, adapt to more.

    Your time and energy and finite resources meaning they need to be directed accordingly. By dedicating 6-12 months of your life to getting in shape, you can spend the rest of your life using your body in a way that is performance driven and never have to worry about dieting again. 

    Personally, I have certain strength and cardiovascular goals I want to hit that don’t require me to alter my body composition in any way. I’m already at my ideal weight/body fat percentage meaning I can train more, eat more and continue moving forward one day at a time. 

    Looking back, I was seriously shooting myself in the foot with all the activity I was doing while dieting down which in my opinion, led to all sorts of problems where I was waking up at 2:00am each morning, consuming a lot of caffeine and having very little energy left for other things outside of exercise. 

    My bloodwork showed hypogonadal levels of testosterone and sky high levels of SHBG (sex hormone binding globulin) which is NOT ideal for performance or health. I was pushing hard without the resources to actually adapt. It was a miracle I didn’t hurt myself!

    I am in a much better place these days and with what I know now, if I had to diet down again I would do the following:
    • Resistance train 4 days a week with a focus on progressive overload.
    • keep my step count between 10-15k per day.
    • keep cardiovascular work to a minimum. 
    • Let my diet do the work.
    I believe I would get into similar levels of condition without compromising my health and/or performance in other areas. 

    From here, I would slowly start reverse dieting to a body weight where I feel back to “normal” and then start chasing my more important performance goals such as increasing my FTP (functional threshold power) in cycling and chasing more high end gymnastic based skills.

    Hindsight is a beautiful thing and even though I can’t change what I did, I can use that hindsight to help other people just like you and our members to take a more intelligent approach when it comes to tackling multiple goals.

    Thanks for reading!
    Ivan GavranicIvan Gavranic

    Ivan Gavranic is RNT’s Head of Applied Research, where his focus is on translating scientific research into real world practical applications for our members. As one of our leading coaches based in Australia, Ivan has lived and breathed transformation for over ten years, staying now at sub 6% body fat year round, he continues to focus on attaining calisthenic and gymnastic skills you only see in the movies!

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