RED-S: Long-Term Consequences & Recovery

In the previous part of this series, we looked at what low energy availability (LEA) is, how it might eventually lead to relative energy deficiency in sport (RED-S), and the short-term symptoms. Now it’s time to talk about some of the long-term consequences and how you can bounce back.

Can RED-S lead to injuries?

Dealing with acute, short-term LEA can be frustrating enough, but if it continues for longer periods of time, you might start to notice more serious health issues developing and bigger drop-offs in your training and recovery. As with inadequate vitamin D and calcium intake, chronic LEA increases the risk of low bone mineral density and decreased bone strength, contributing to a higher incidence of stress fractures. If you’re already dealing with a bone injury, consuming inadequate calories and lack of solid nutrition can slow your healing process. RED-S might also elevate your chances of developing other overuse injuries.

RED-S & menstrual cycle changes

In last week’s post, I shared that 30 kcal per kilogram of fat-free mass (FFM) or less was considered to be the danger zone for LEA. While this is a good clinical rule of thumb, some studies have shown that women who were above this threshold still had menstrual functions that were all over the map. Researchers from Penn State found that multiple kinds of disturbances – including luteal phase defect, anovulation, oligomenorrhea – can become more frequent when female athletes have persistent energy deficits. 

What are other consequences of RED-S?

According to the International Olympic Committee, RED-S doesn’t merely compromise bone health and disturb the menstrual cycle. Persistent LEA can also cause a whole host of health issues and exacerbate existing ones in many other body systems. Some of the long-term effects include:


  • Disrupted levels of estrogen and progesterone in women
  • Low testosterone in men


  • A 2015 study on the female athlete triad (the interrelationship between LEA, menstrual function, and bone mineral density) found 53 percent of LEA participants had a decreased resting metabolic rate (RMR). Others were struggling with low bone density, high cholesterol, and low blood sugar   
  • Impaired ability to use glucose effectively and sometimes low blood glucose levels 


  • Low ferritin and iron deficiency anemia 
  • Iron deficiency can further decrease appetite


  • Higher lipids
  • Cardiac abnormalities like lower or higher heart rate


  • Delayed or faster gastric emptying
  • Diarrhea and constipation


  • Increased risk of illness
  • Decreased immunity


  • Depression and anxiety
  • Mood disturbances 

Growth and Development

  • Stunted growth in adolescents
  • Decreased growth hormone release

What nutrition changes can I make to increase energy intake?

When someone finds out they have RED-S, the logical conclusion is that they simply need to eat more. This can certainly be the case, as having an overall calorie deficit is a major part of the problem. However, a bit more nuance is usually needed to remedy the issue, which is where a dietitian can help. When I look at a client’s eating habits across an entire day, I often see that there are certain times when they aren’t taking in enough energy, leading to lopsided energy intake over a 24-hour period and an overall deficit. 

For example, perhaps your mornings are crazy because of your commute or school drop-off, so you often skip breakfast. Or maybe work gets so busy that you don’t eat lunch several days a week. So by the time you get to midafternoon, you’re already energy deficient. Then you go and run hard, digging an even deeper hole. Once you’ve had help to pinpoint specific fueling gaps, you can start to fill these so that you have enough energy for daily life and training. 

What are some other ways that a sports dietitian can help with RED-S?

A qualified professional can confirm whether or not you have RED-S or are struggling with LEA, and then create a comprehensive plan to help you bounce back. In addition to identifying gaps in your eating schedule, they can suggest better choices for snacks and meals, recommend supplements if needed, and take into account the big picture of your training, recovery, and lifestyle to help you find a more sustainable energy balance. As I wrote in a previous post, it’s time to stop being scared of carbs and embrace a well-balanced approach to nutrition.  

Sometimes the solutions to low energy availability are simple ones, such as incorporating more calorie-dense foods. For example, you could start adding a couple of spoonfuls of nut or seed butter to your post-workout shower shake. Frequency is another easy variable to change, as adding morning and afternoon snacks will increase your energy intake. Some of my clients have also benefited from eating a pre-bedtime snack, like a Greek yogurt parfait with berries & granola. Others have started eating a second breakfast. Ultimately, you have to fuel like you hope to perform, live, and recover. 

How do I start increasing energy availability?

Most people’s eating is primarily directed by their appetite, but remember that this is often a lagging indicator of needing energy and can be disrupted by your sleep pattern, exercise, caffeine, and other factors. You’ll be better off planning for your fueling needs like you would build out your training sessions. A good rule of thumb is to fit in at least three meals and two snacks each day, not going more than 3 hours without eating and focusing on balancing adequate carbs, protein & fat. While it’s important to get enough carbs and protein, they only contain four calories per gram, whereas fat has nine, making it an easy way to up your energy intake.   

Also make sure you surround your energy expenditure – whether that’s a formalized session like a run or gym workout, or family activities – with more nutrition. In other words, eat before, during (when needed), and after exercise, and recognize that more intensity and volume will increase your fueling needs, such as if you start strength training or doing some two-a-days. It’s easy to get discouraged if you have RED-S/LEA but know that you have the power to overcome this and that there are people out there with the passion and knowledge to help you recover. Some of my clients have reported starting to feel and perform better in a few days once they increase their energy availability. 

If after trying these tips you still can’t keep up with your energy needs, then try cutting back on your training temporarily. Then when your schedule and lifestyle allow, scale up your workouts and nutrition again simultaneously. 

If you’re struggling with LEA or RED-S and need help, please reach out. I’ve helped many clients to overcome this issue and would welcome the chance to get you back on the path to optimal performance and health.

1.Nancy I Williams et al, “Magnitude of Daily Energy Deficit Predicts Frequency but not Severity of Menstrual Disturbances Associated with Exercise and Caloric Restriction,” American Journal of Physiology, Endocrinology, and Metabolism, January 2015, available online at 2.Margo Mountjoy et al, “International Olympic Committee (IOC) Consensus Statement on Relative Energy Deficiency in Sport (RED-S): 2018 Update,” International Journal of Sport Nutrition and Exercise Metabolism, July 2018, available online at Melin et al, “Energy Availability and the Female Athlete Triad in Elite Endurance Athletes,” Scandinavian Journal of Medicine & Science in Sports, October 2015, available online at

Disclaimer: The content in our blog articles provides generalized nutrition guidance. The information above may not apply to everyone. For personalized recommendations, please reach out to your sports dietitian. Individuals who may chose to implement nutrition changes agree that Featherstone Nutrition is not responsible for any injury, damage or loss related to those changes or participation.