Relative Energy Deficiency in Sports and Fitness

It seems like common sense that athletes demand a high level of energy and nutrients to support their training. Still, it’s often that recreationally active adults assume a healthy and fit lifestyle means hyper-focus on eating “healthy” which can mean different things to different people, depending on what diet trends they follow on social media or have been exposed to. As sports dietitians, we have experience with professional and collegiate athletes, recreational endurance and strength athletes, as well as consulting with major fitness clubs. We can tell you without a research study (even though we’ll cite some) that it’s not only athletes that under-fuel their activity. It’s also everyday exercisers, just like you. That’s why we’re diving into Relative Energy Deficiency in Sports and Fitness. Whether intentional or inadvertent, read on to see how under eating may be impacting your health and performance.

Signs you aren’t eating enough for fitness

In our experiences, we see a lot of inadvertent under-fueling in athletes – including those who are recreationally competing, not just collegiate and pro. For recreational exercisers trying to maintain or improve their fitness, inadvertent under-fueling may look more like chronic dieting or what other gym goers and influencers consider a “healthy lifestyle”. Unfortunately, with most accurate messaging around health speaking to those who live mostly sedentary lifestyles, messaging can get confusing and those who exercise often – along with busy, active lifestyles outside of the gym – can wind up eating too little to support all their body needs to do.

When you’re in too much of a calorie deficit, your body enters “Low Energy Availability” or LEA. This is when you aren’t eating enough to support both your training and daily activity on top of your basic body functions. Think of all your central nervous system is controlling each day to keep you alive. It doesn’t sound like much, but maintaining your body temperature, supporting normal tissue turnover, breathing, healthy cardiovascular function, hormone production – it all takes a lot of energy. So, if you’re under fueling long term, your body may in turn slow day physiological functions, leading to the following:

Potential Health Consequences of Low Energy Availability:

• Reduced immune function – getting sick often
• Loss of menstrual function, or low hormone levels in males
• Loss of bone mass, increasing risk of fracture
• Impaired heart health and metabolic function
  • Poor blood glucose and lipid levels
• Poor mental health and/or cognitive declines
  • May look like anxiety, difficulty concentrating, depression
• Slowed energy metabolism and poor tissue turnover
  • Can present as hair thinning and loss, brittle nails, skin issues
• GI discomfort: bloating, gas, constipation

Potential Performance Consequences of Low Energy Availability:

• Poor responses to and progress with training
• Slowed recovery and/or decreased muscle strength
• Decreased power and/or endurance
• Decreased motivation and enjoyment with exercise
• Poor cognitive performance
• Increased risk of injury

Causes of low energy intake for sports and fitness

Weight loss goals

There is nothing abnormal about the desire to lose weight. What is abnormal is how quickly people expect to lose weight, how people with a “normal” BMI and metabolically healthy body composition want to get as lean as possible, and the drastic measures people will go to in order to lose weight. Not to mention that what is “drastic” seems to be reasonable based on not only what is seen on social media and the media, but also at times what doctors recommend in their 10 minutes with patients in a typical PCP office.

Even for those who support more “rapid” intentional weight loss, 2 lbs per week is considered the highest healthy loss per week that may be associated with “successful” weight loss, or keeping the weight off for at least one year after reaching an end weight. For people who are out there looking to “lose the last 5 lbs”, I always first ask why and at what cost? Does losing 5 more pounds get you to a college weight that no longer fits your life stage? Is it a pre-pregnancy or pre-menopausal weight that you’re holding onto in your mind? Does reaching that weight mean sacrificing food enjoyment and a social life while increasing stress?

Chronic dieting

For those that have yo-yo’d with weight loss, fall into all-or-nothing diet patterns, and/or rode the binge-restrict cycle for years, your metabolism may be trying to protect you already. Even with a binge once a week, a chronic calorie deficit may ensue causing your body to slow down basic functions to protect you.

Lack of structure

When LEA is truly inadvertent, it’s often due to lack of a consistent eating schedule with or without knowledge of what an adequate and nutritious eating pattern should look like. I’m looking at you if you’re a young adult in over-achiever mode with intense workouts on your schedule and a high stress job you’re putting too many hours into that leaves you forgetting to snack or even eat lunch somedays. Or if you’re a busy parent prioritizing fitness, while working and shuttling your kids to every activity, leaving you to just eat a yogurt or a protein bar for lunch. The chronic lack of fueling adds up.

A new fitness routine

Eat a well-balanced diet with 3 balanced meals a day? Whether you signed up for your first half marathon or you started hitting the gym for an hour 5 times per week, sticking with your old eating pattern may work at first. Over time though, not adding in a snack, more carbs at lunch, or fuel during workouts may catch up to you with the signs and symptoms listed above. Training in a similar way to athletes requires a bit of an athlete mentality, especially when you’re new to this level of training. Or if you forget how long it’s been since your high school or college athlete days – your body will be under extra stress and require more energy to re-adapt. Otherwise, your new goals may instead compromise short and long term health, while adding unnecessary stress. 

How to eat adequately to support fitness

Everyone is different not only in how they got to a point of under-fueling, but also in what they need to adjust – both mentally and habit wise – to better support themselves. Here’s some things to consider:

Eating Enough for Endurance Training

Whether you’re a seasoned marathoner or someone who’s training for their first sprint triathlon, this video dives into this topic with more specificity to endurance.

Need tips on what to eat marathon day or race day for your triathlon?
Check out my detailed What to Eat Before a Marathon  piece for Clif bar.

Looking for dietitian and community support?

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