By Rebecca Fallihee
If you read running websites or magazines, view social media accounts of various athletes, and perhaps overhear conversations in your run community, in the past few years you may have noticed an increased attention to a topic called RED-S (pronounced reds), or relative energy deficiency in sport, which occurs when a wide range of signs and symptoms throughout the body occur and negatively impact health and performance. When RED-S occurs, its cause is low energy availability.
Low energy availability is most accurately calculated by removing the energy cost of your daily exercise from your total dietary caloric (energy) intake, and then having what is left not being enough energy (calories) to support the body’s normal physiological function, such as bone metabolism, endocrine/hormones, reproductive system, etc. Low energy availability is associated with downregulation and impairment of key physiological processes due to the lack of adequate energy support.
That’s the scientific definition. I simply call it “Not eating enough for your activity level.” Even simpler that translates to not eating enough.
Not Eating Enough
For a couple decades, one piece of the larger puzzle of relative energy deficiency has been known about in the sporting community. That piece is the Female Athlete Triad, in which female athletes present with a pattern of low energy availability with or without an eating disorder, in relationship with amenorrhea (lack of menstrual cycle), or irregular menstrual cycle, and low bone density leading to osteopenia and osteoporosis. What we now know is that the Female Athlete Triad is just one section of a larger picture of pathophysiology that can present in athletes with long-term low energy availability. And it is not just a female athlete concern.
When active individuals are not eating enough for their on-the-move lifestyles – the body, because it is wise, makes decisions about where it is going to prioritize its precious calories. So if you’re going to go for a long run in the forest for several hours, followed by an evening hike or weight session, and then follow with something similar tomorrow and the next day, and throw in a weekend of back-to-back long runs, AND you’re routinely not eating enough to meet your caloric needs, the body is going to choose where to spend those nutrients—because when this precious energy is used for one function, it is not available for another one.
Essentially, this pattern adopted long term puts your system into survival mode.
And it plays out along these lines as your body says, “Well, if you’re going to make me go do these workouts, I’ll put my energy here, though maybe with a little less pep, energy, and high-intensity ability, but I’ve got to compromise somewhere, so I’ll make a trade-off over here with bone metabolism, or over here with female reproductive hormones or thyroid health, or immune function, or over here with the GI system and the ability to break down nutrients in food (because digestive enzymes are made of proteins which may be lacking in the diet), or muscle and tissue repair or”…. and the list goes on.
On Our Radar
So why is this topic suddenly on more people's radar? One, we have more research and knowledge on the expanded umbrella of RED-S and the widespread physiological consequences of being at a long-term energy deficit. But also because it’s fairly common for active individuals to not realize they’ve adopted many of the beliefs of the diet industry into their eating habits over the years. Or they may simply be eating to hunger levels, and still not be eating enough.
And, just eating to hunger can sometimes be misleading for us as highly active folks. For instance, many athletes have a suppressed appetite after long or intense workouts or races. In those cases, it’s ideal to replace nutrients after exercise—but when digestion is compromised, the body won’t metabolize the food as it should—hence the potential for working with a nutrition professional to help get the digestive system back to balance. Alternatively, we might need to learn to recognize the symptoms of hunger that often go beyond an empty stomach.
Within-Day Energy Balance
The other side of that low energy availability coin can also mean within-day energy balance. Meaning we don’t stack the majority of our calories into one meal or couple of hours of the day. Eating to fullness, or 80 percent of fullness, is recommended, but if you ever notice you get to the point of overeating after exercise by having excessively large meals that seem to top you up beyond fullness, it is often because of low energy intake throughout the day fueling a need for more food spread throughout the hours. This can often occur after a long run. In this case, you can train your body to tolerate more fuel during a run, and then you’ll likely both recover better, but will also have stressed your body less with the huge energy deficits and then subsequent deposits.
With a more even or adequate energy intake before and during a long workout, you can avoid that ravenous feeling of needing to eat quickly and impulsively.
A Self-Assessment to Help Navigate Your Energy Needs
If this topic has kindled your curiosity about meeting your own energy needs, my suggestion is to start with a self-assessment rather than calculating calories and meticulously tracking meals—those can sometimes be helpful, but they can just as easily be highly inaccurate and lead to neurotic food obsession and tracking. Ask yourself these questions:
– Am I frequently sick more than a couple times per year?
– Do I struggle with fatigue frequently?
– Am I improving in my performance - or have plateaued or gone backwards despite training?
– Have I had a lot of injuries?
– How’s my overall health? Basic blood work results hold a plethora of data on how the body is ‘performing’ internally.
– How is my menstrual cycle and/or sex drive? Women have a little advantage here in that any menstrual symptoms or irregularities* are symptoms telling you to heed warning because there’s a larger health story.
– Do I have a lot of gut upset / discomfort, or food intolerances?
– Am I routinely irritable, depressed, anxious, or have decreased concentration?
– Am I sleeping well?
– and if you have teammates or friends/family that you work out with regularly: Do I eat less than my teammates but have a higher body fat? This is subjective of course because every body is different, but higher body fat and eating less is also a tell-tale sign, since lower metabolic rate occurs with lower energy availability, meaning you might be eating less but weighing more or having more “cushion” than previously.
– and one more because it can become prevalent with long-term low energy availability: Am I thinking about food ALL THE TIME? We know from eating disorder and starvation studies that chronically deprived individuals become obsessed with food, far beyond just being interested in food.
Where to go from here?
Above all, food and exercise should make you feel good. The goal is to be aware and in tune with yourself and your body’s ability to show you signs that something may not feel right or as great as it should.
And you may benefit from professional guidance. If you’re confused or concerned about your needs, or would like a professional opinion, I encourage you to work with a nutrition professional for more personalized support.
*Women on hormonal birth control will not have the same ability to use their menstrual cycle to gauge abnormalities, since it is designed to eliminate ovulation and the normal hormonal fluctuation that occurs. If symptoms or irregularities occur without birth control, that is a vital sign that your body has an imbalance somewhere.
The information shared in this article does not intend to treat, diagnose, cure, or prevent any disease.
Rebecca Fallihee is a board-certified clinical nutritionist and licensed dietician/nutritionist, educator, and athlete living in Eugene, Oregon.
Jeukendrup, A. (2013). The New Carbohydrate Intake Recommendations. Nutritional Coaching Strategy to Modulate Training Efficiency. Nestlé Nutrition Institute Workshop Series,63-71. doi:10.1159/000345820
Jeukendrup, A. E. (2017). Training the Gut for Athletes. Sports Medicine (Auckland, N.z.), 47(Suppl 1), 101–110. http://doi.org/10.1007/s40279-017-0690-6.
McKay, A.K.A., Pyne, D.B., Burke, L.M. and Peeling, P. (2020). Iron Metabolism: Interactions with Energy and Carbohydrate Availability. Nutrients, 12: 3692. https://doi.org/10.3390/nu12123692.
Torstveit, MK., Fahrenholtz, IL., stenqvist, TB., Svlta, O., Melin, A. (2018). Within-day energy deficiency and metabolic perturbation in male endurance athletes.
Mini-Meals to Keep You Going
Ideally we spread our meals out throughout the day and leave time in between them for full digestion to occur, so we’re not throwing more food in when the last meal hasn’t fully digested. This causes more problems over time in other ways. In an ideal routine, aim for eating at intervals of four to six hours after a full meal, and two to four hours after a light meal instead of snacking continuously all day. Here are three snack ideas for those in-between times:
Wonder Woman Bars
These are great mini-snacks for times of medium-high training volume that can be prepped ahead and eaten when time is short. Flavors and ingredients can be changed up. The combination of blackstrap molasses, hemp protein, and camu camu powder make these rich in iron, as well as the vitamin C needed to absorb it. These two nutrients are often low in endurance athletes, not just females. This is even more the case in those that aren’t meeting their daily energy needs for all that time on feet! If camu camu powder is difficult to find, another that might be (slightly) easier is rose hips instead. Simply gather a little handful from the season’s spent wild roses while out on your long run this fall, bring them home, and chop or grind them up into the mixture. This recipe is adapted from The Cycling Chef, Alan Murchison, who gave it the fun title.
Prep: 10-15 minutes | Makes: makes 8-12, depending on size
1 ½ tsp. camu camu powder
¼ tsp. salt
2 tsp. blackstrap molasses
6-8 drops orange or lemon essential oil (or orange zest) - totally optional but adds zing!)
6 Tbs. seed or nut butter of choice (almond or sunflower seed is great!)
6 Tbs. hemp protein (or unflavored protein)
½ cup chopped dates
½ cup chopped apricots
¼ cup tart cherries or chopped prunes
¼ cup pecans or hazelnuts, chopped
1 cup crispy rice cereal (like Rice Krispies)
- Combine the camu camu powder, salt, molasses, dates, orange or lemon oil, nut butter, and hemp protein in a food processor. Blend until combined.
- Stir in the apricots, tart cherries or prunes, and chopped pecans, along with the rice cereal. You can pulse the food processor just a little to combine everything, but you want these add-ins to retain their texture. Add 1-2 tablespoons of water if the mixture is slightly dry.
- Tip into a small rectangular dish and press firmly with a rubber spatula or your fingers to flatten smoothly. Refrigerate for at least a couple hours until set and then slice into bars.
- They will last in the fridge for at least two weeks with no change in texture/consistency.
William’s Oatmeal Raisin Granola Bites
Like a minimal ingredient granola bar, these are the polar opposite in terms of simplicity from the snack bar above, and my husband William’s preferred snack bar/bite. We often interchange the hemp seeds with lightly toasted sunflower seeds or brazil nuts every other batch.
Prep: 10-15 minutes | Makes: 12
1 ¼ cups oatmeal (quick-cook) is best
¼ cup hemp seeds
¼ cup raisins
⅛ tsp. salt
¼ cup brown rice syrup or honey
½ cup peanut butter or almond butter (any nut/seed butter works!)
- Mix all ingredients together well, cookie scoop into balls, or press into squares.
Sweet Potato Spanish Tortilla
Tortilla, which is really a Spanish omelet, is generally made with white potatoes and cooked in lots of olive oil in the pan before the eggs are added. For ease, I like to roast the sweet potato ahead, and then dice and gently crisp the edges in just a bit of oil. This method also makes this come together in a flash— perfect for a fast meal for days that have a lot of rush. After making, the tortilla can also be stored in the fridge for a couple of days, sliced into wedges, and eaten as a quick snack.
Prep: roast the sweet potato | Cook: 25 minutes | Serves: 2-4
1-2 large sweet potatoes (250 grams)
½-3/4 tsp. sea salt
4 eggs, preferably pasture-raised
2 handfuls of dark greens such as arugula, spinach, amaranth or kale, chopped
For a full meal, add a cooked grain or toast
- Preheat the oven to 400°F / 200°C. Scrub the sweet potato(es) and stab it a few times with a fork or knife to allow steam to escape. Roast in the oven until just soft, about 40 minutes.
- When the potato is cooked, dice it into ½-inch cubes. Then heat a little olive oil in a 7 to 8-inch sauté pan over medium heat. Sauté the diced sweet potato for 3-5 minutes, just until the edges begin to turn golden. Add in the greens and cook 1-2 minutes more until they are wilted and incorporated. Season with the salt.
- Meanwhile, whisk the eggs in a bowl. Then add the eggs over the sweet potato and greens.
- Let it cook for about two minutes and then place a clean plate over the pan, flip the tortilla onto the plate, and then slide the uncooked side back into the pan. Heat for 3-4 more minutes until cooked through. It should be firm and golden once ready.
- Remove from heat and let it cool for a few minutes. Cut into wedges and serve with a couple slices of toast or a cooked whole grain to make a more complete meal.