Podcast Episode 90 Transcript – Underfueling & RED-S

Aidan:

Hello and welcome back to the Ideal Nutrition podcast. My name is Aidan Muir and I’m here with my co-host, Leah Higl. This is episode 90 where we are going to be talking about underfueling and the implications of it, including a syndrome known as RED-S.

Leah:

Let’s start with the very basics in terms of going through the definition of RED-S and what it actually stands for. The acronym itself stands for relative energy deficiency in sport, and then the definition is the impairment of physiological function caused by a deficit in a person’s energy intake relative to the amount required to maintain optimal health, homeostasis, growth, and activities of daily living and sport. RED is used to be known as the female athlete triad and then it became RED-S. The female athlete triad was a little bit more specific in its definition. It was specific to female athletes and it was energy deficiency that was mostly secondary to disordered eating patterns and included irregular menstrual cycles related to low estrogen, which eventually led to low bone mineral density. But the term RED-S is a little bit more broad in that it takes into account that it’s not only female athletes that can be affected by low energy availability. It can occur in male athletes as well and it can have a negative impact just beyond menstrual cycle and bone health and doesn’t necessarily have to include aspects of disordered eating.

Aidan:

Since RED-S is typically thought to be linked with low energy availability, it makes sense to define what that is. I’m going to start, before I go into definitions about it, talking about that there are some flaws that I see in the definitions of it, but we’ll get to the flaws later. I think it makes sense to start with the simple definition. It’s simply measured by measuring calorie intake and calorie expenditure solely through exercise. Basically, you eat a certain amount of calories, you burn a certain amount through exercise, and then you also burn calories through all these other functions that the body does. The logic is if you’ve burnt a lot of calories through exercise and you only have a small portion of your calorie intake leftover to fuel these other functions, you’re in a state of low energy availability. Putting some numbers on an example, this could look like somebody eating 1,900 calories and then burning a thousand calories through exercise.

The logic here would be that only 900 calories are left over for other functions, which theoretically is not a lot of calories left over for these other functions and could be considered to be a state of low energy availability. While there aren’t specific guidelines or anything like that, there has been some research attempting to put numbers around this, utilizing fat-free masses, that kind of metric. Using that research, low energy availability can be considered to be identified in athletes consuming less than 30 calories per kilo of fat-free mass, I’ll add some context around that, and optimal energy availability is considered to be greater than 45 calories per kilo fat-free mass. Adding context because you can’t really do the math in your head in that super quickly. For an 80-kilo athlete with 65 kilograms of fat-free mass, this would put what would be considered low energy availability at less than 1,950 calories per day. Optimal would be at greater than 2,925 calories per day based on that definition.

Leah:

Yeah. But quickly addressing some of the flaws in that equation, I suppose, is that firstly, obviously not all athletes have really high training loads. We know the research that these numbers came from is based mostly on athletes with really high training loads. For example, there are plenty of 80 kilos strength athletes who train, say four, maybe five times a week, but they don’t really do much else outside of that. Training load’s pretty moderate, maybe a bit of a sedentary lifestyle outside of training, and if they got almost 3,000 calories per day or that 2,900, that may put them into an unnecessary calorie surplus in following that, so it may be excessive for them. Whilst maybe an endurance athlete, if you’re looking, let’s say an Ironman athlete with a really high training load, maybe that is more applicable to them than that strength training athlete.

That is one flaw in the system that we can see as pretty evident and why still individual assessment is really necessary. The other main issue is that the actual equation doesn’t take into account fat stores. We know that fat stores can be utilized to fuel functions. The whole concept of eating the 1,900 calories and then burning a thousand calories, leaving only 900 calories left for these other functions, well, that can be skewed by the fact that if someone had a higher body fat percentage, they could have more to draw on from that body fat than someone who is very, very lean. So leanness is another variable in this. It’s not to say that people with a higher body fat percentage are not at all at risk of low energy availability, but people that are leaner are probably at a higher risk of RED.

Aidan:

Yeah. Even though there is flaws in the system, we still need some form of system for quantifying this.

That’s why I still like it. We can see the obvious flaws of it not taking into account these fat stores and also the guidelines not being applicable to everybody. But if you take that out and you just take out the guidelines and just look at the individual assessment and then acknowledge that if people are super lean, they’re going to be less likely to draw on their fat stores to fuel their functions. If somebody has a lot of body fat, they’re going to be a little bit more likely to do it. It still leaves us with the common thing of being like, if you have a low calorie intake in relation to your training volume, you can still end up with some of these issues even if you have a bit more body fat still. It’s not just based on leanness, which without any system of trying to quantify this in any way, shape or form, you could then assume that only lean people are going to run into this problem.

Leah:

Yeah. And in general, that equation is still a good way to assess, I guess someone’s risk and then do an individual assessment. If you are an athlete who does have a lower training load and you go, oh, well I am, I guess, meeting the requirements for low energy availability, but I don’t have any of the symptoms of low energy availability, then it’s probably not applicable to you. That individual assessment is still so important.

Aidan:

Yeah, for sure. The next thing we’re going to talk about is, how does this affect health and performance? We’ve touched on a few things, particularly in relation to female athlete triad or what it was previously known as, but I’m going to start off just looking at the health stuff, not performance stuff for this section. From a health perspective, the most obvious sign in women is loss of period and then the fertility concerns that come alongside that because ovulation’s not occurring and everything like that. This can obviously be masked by other stuff like if somebody’s on oral contraception, we won’t be able to measure this. That’s obviously one major red flag that is tipping us off that RED-S is occurring. As Leah mentioned, decreased bone mineral density is another telltale sign of this happening, and that leads to long-term osteoporosis.

This is something that I think of as a concern more so long term, but it happens relatively quickly over a 12-month duration. [inaudible 00:07:57] you can lose a considerable amount of bone. There’s certain athletes who want to be in the sport for 12 plus years and it’s like, well, you can’t be in a state of low energy availability for 12 plus years and still perform well in your sport and have a healthy life and all of this kind of things, which makes it more important to address this. Particularly in younger athletes from a health perspective, impairments and growth and development, obviously, similar concepts would apply more so from a performance perspective than older athletes, but this is one to be aware of. More frequent illnesses and longer duration, this is another thing that from a health perspective matters, which could also carry over to performance and then irritability in general, which makes sense because there’s not many calories to go around. It makes sense if you start feeling some of these things.

Leah:

And then in terms of performance-related things you can look out for is reduced ability to build muscle. That’s definitely one. Your body’s just not going to have enough energy to draw on to build that muscle. It’s just not going to be prioritized. Reduced endurance, higher risk of stress fractures, but also just higher risk of illnesses that affect your training. Like if you’re consistently getting sick, that could be a sign of RED-S as well. Reduced concentration and coordination, so that psychological aspect of performance, and just a general increased injury risk. If you are someone who is constantly getting injured, then that also can be a telltale sign of RED-S.

Aidan:

So how do we manage RED-S or just underfueling in general even if it’s not necessarily RED-S? The simple solution is just increasing calories or reducing training. It’s got to be one or both of those things to solve it. That’s simple, but as you can imagine, individual circumstances are quite complex because what if somebody is in a sport where their training load wants to be high, they’re aware of the risks and they still want to train in that way? What do we do? Well, then we can’t really change that variable if that’s what is going to happen, so we need to increase calories in that case. But what if somebody has a limited appetite, they struggle to eat enough calories to solve this kind of problem? Then maybe we need to start looking at energy dense foods or maybe even higher calorie shakes or liquid calories, things that are easier to get more calories in. The simple solution is increasing calories or reducing training, but the practicalities of it is pretty individual.

Leah:

In addition to rectifying the actual energy deficiency, the current body of research also encourages a higher calcium intake and good vitamin D levels, specifically for the bone health aspect of all of this. This is particularly pointed towards athletes who also experience loss of or irregular periods due to low estrogen levels because they are more likely to experience the decrease in bone mineral density from RED-S or low energy availability. The current recommendations include aiming for 1,500 milligrams of calcium per day, which is significantly higher than the RDI, which for most adults is going to be around that thousand milligram mark. The recommendation is a little bit higher, more akin to the recommendations for post-menopausal people. Then in addition to that, there’s also a recommendation around vitamin D supplementation, particularly if levels are low. It’s recommended anywhere between 1,500 to 2,000 international units per day to lift your levels, but that can be a little bit variable depending on other factors in terms of dietary intake of vitamin D and sun exposure.

Always good to have your blood checked and see where that is sitting. But there are those obvious recommendations around bone mineral density and bone health in addition to the energy deficiency stuff. Then I suppose there’s also the HA stuff that would come into play if your period is missing. Then there are potentially other things that you may want to do around restoring your period as part of the intervention. So that could be looking at adequate fat intake, fueling your training with carbohydrates adequately and more specific things around your intake.

Aidan:

Another area that is complex is whether RED-S can always be avoided. That sounds simple. You might be listening [inaudible 00:12:31] being like, yes, we should always avoid it, and I agree. We should avoid it in pretty much all cases where possible, but in some rare cases, it might not be possible. One example of this, probably the less interesting to me, but still a potential example is during certain phases of endurance training in really high-level athletes. Sometimes people need to dip into a state, maybe not need, but sometimes people are going to dip into a state of low energy availability to get as lean as they need to be for optimal performance while also building up a lot of kilometers in their training to prepare for an event. Sometimes that needs to happen and it’s part of the sport. I reckon if you look at top level athletes in endurance sports, a lot of them are experiencing some of these symptoms at some phase of their training.

It’s like if somebody’s choosing to do that, then that is a price that comes alongside that. Ideally, if somebody has to do that or is going to do that, we are going to risk mitigation mode where it’s like, how can we do this in the healthiest way possible? Because even as I said, you can’t be in this state for 12 plus years, so it’s like even if you had to do it for your sport, you can’t be in this phase year round. The other area I’m a little bit more passionate about is body building. The vast majority of women who compete in body building get HA towards the end of their contest preparations, so they lose their period. Men, we obviously don’t have that measurable of where we can say, oh, they’ve lost their period there in a state of low energy availability, but we do see all the implications that go on hormonally. We see their thyroid function dropping and all of these other things too. They would be in a state of low energy availability as well, we just don’t have easy to measure metrics.

But this is where it gets interesting because it’s like a decade ago, most people would’ve looked and been like, yeah, body building is an unhealthy pursuit and just thinking like that surprise people are willing to pay to [inaudible 00:14:30]. They’re not doing this for health purposes. They’re sometimes aware, sometimes unaware of the consequences that come alongside it, but there is this thought process that’s like people are aware that this is an unhealthy pursuit, but they’re still pursuing it anyway. But then as knowledge of low energy availability has come into play, I’ve seen a lot of coaches and stuff like this going to this kind of mindset of being like, we should never have a state of low energy availability, which as I said, that’s a good thing. We should be focusing on this where possible. But it leads to an interesting question where I see a lot of people who are strictly in the body building world and not in the other area of energy availability research or anything like that, just being like, would people get stage lean if they maintained good energy availability throughout their entire prep?

If you had a sole focus of maintaining good energy availability, there is an argument to be made that maybe certain people don’t get stage lean. If we look at it from that older school perspective, we can still look at it from the perspective of being like, okay, this is an unhealthy pursuit. How do we manage it the best? Do we get stage lean? We don’t drag out the prep to be so long that they’re in this state of low energy availability for super, super long, but we also don’t make it so quick that they have to go so, so low calorie to get stage lean. So we’re striking for that middle ground and then we get out of it as soon as realistically possible. We don’t try to stay anywhere near stage lean right after a competition. We intentionally gain some body fat in a relatively controlled fashion, so it’s not gaining super, super quickly, but it’s also not dragging the process out. We address the state of low energy availability in a relatively quick timeframe if possible.

Leah:

Yeah. It specifically, I think, makes an argument if you’ve had to dip into low energy availability to get stage lean for not reverse dieting out of a prep competition in terms of just being slightly more aggressive with that approach postshow.

Aidan:

There’s a term for that now called recovery diets. Reverse dieting is where you slowly add calories meticulously and you add like a hundred calories per week, whereas a recovery diet is not sending it, but it’s like, no, the goal here is to gain a bit of body fat to get back to this healthy state. In the process of doing that, you’ll obviously have good energy availability in the weeks that you’re doing that because you have a lot more calories in comparison to your training volume compared to where it previously would’ve been at before the competition.

Leah:

I think generally as an athlete, RED-S is a great thing to generally be aware of. If you feel you are displaying some of the symptoms of low energy availability, it is definitely best to seek out help sooner rather than later because it’s something you will want to address if you are an athlete who is intentionally putting yourself in this place. Once you’ve reached a goal, whether it’s a body building show or a race or whatever, it makes sense to be a little bit more aggressive in your recovery post that event. But overall, this has been episode 90 of the Ideal Nutrition podcast. If you could please leave a rating and review, that would be greatly appreciated. But other than that, thanks for tuning in.