It's no surprise that endurance sport places high-demands on the body. However the implications of these demands are not always obvious to the athlete.
While athletes may recognize the signs and symptoms of musculoskeletal, hormonal, immune, and neurological systems, athletes may be oblivious to the effects of insufficient calories to their performance and health.
Relative Energy Deficiency in Sport
In recent years, sports medicine research, and authorities like the International Olympic Committee (IOC) have paid particular attention to the associated risks of insufficient energy (calories) of athletes. In 2014 the IOC termed the condition, or syndrome 'REDs' - Relative Energy Deficiency in Sport.
The term seeks to capture the performance and health degradation of an athlete due to relative insufficient caloric supply. This may come about, from intentional eating disorders, food-restriction practices, and/or indirectly through high training demands of the athlete.
While the syndrome has been more prominently published in relation to women's health and performance, studies would show that men, the young and aged are all at risk of REDs. While the syndrome has wide-spread relevance to any competitive athlete, it presents higher risk to endurance athletes (marathon, cycling, triathlon), sports which emphasize a thin physique (figure skating, gymnastics or diving), and sports which require a 'weigh-in' (wrestling, boxing etc.) as part of competition.
Signs and Symptoms to Watch For
Degradation in endurance, or strength, frequent injuries, even co-ordination and cognitive focus can all be performance related signs of REDs. From a health perspective, there's a wider range signals associated with REDs, notably, moodiness, depressive states, menstrual cycle disruption, lowered bone density, stress-fractures, more frequent infections and lower heart-rates with dizziness.
In 2023, the IOC published a Clinical Assessment Tool (CAT) for REDs establishing a three-step process for screening, risk categorization (severity), and physician diagnostic and treatment plans. Should an athlete be concerned regarding their own performance and health, SFuels would recommend athletes visit their preferred sports-medicine provider having experience in REDs.
SFuels Perspective: RIGHT FUEL RIGHT TIME
Our perspective on REDs has several dimensions.
Firstly, optimal energy-fuel choices during training, second every-day (between training) caloric in-take, and finally micro-nutrient status.
1) Training Nutrition: SFuels has consistently advocated the application of the right (type and amount) macro nutrition (carbs, fats and protein) relative to the intensity and duration of training loads. We have framed this the 'RIGHT FUEL at the RIGHT TIME' approach.
It's common practice for athletes and coaches is apply the 'specificity-method' where training blocks, and workloads are 'specific and fluid' relative to the target competitive event. Typically a coach will tune workout specificity around seasons, training blocks relative to the timing of the target competitive event(s). This includes, shifting ratios between aerobic, anerobic/VO2Max sessions, strength, plyometric and other training focus areas. From a physiology perspective, the body will shift its use of fuels between carbohydrates, fats, amino acids and ketones relative to the intensity of the exercise.
SFuels advocates a focus on improving each of these systems - the aerobic system (more fat based), and anaerobic (more glucose based) system, via both training, and specific fuel (carbohydrate, fats, amino acids) use and timing, during training. Research has shown, that the right fuel choices in training can positively amplify training adaptations, and conversely poor fuel choices (and the amount) can have a 'de-training' effect to the athlete.
More detail on optimal fueling protocols can be found in our SFuels Training Guide, and our Fueling Guide which includes our racing fuel recipes. The over-arching goals of the RIGHT FUEL RIGHT TIME model are centered on optimizing endurance performance and lowered Gut/GI distress risk, while also supporting general health-wellbeing.
2) Every-Day Macro Nutrition: It's likely that for the vast majority of athletes, the predominate contributor factor to triggering or avoiding REDs will be the over-arching macro-nutrition (carbs, fats, protein) consumed between workouts, each and every day.
In a published guide by the IOC and The Coca Cola Company (Olympic sponsor), reference is made (though debated) to the minimal daily intake of 30kcals per kilogram of fat-free body mass in females, to avoid impairments to metabolic and hormonal functions and subsequent detriment to sports performance and health. For males, that daily target is less understood, with papers referencing a range of 9-25kcals (per kg/FF body mass).
'While SFuels is aligned to these aggregate caloric targets as noted by authorities - as it relates to endurance athletes, the recommended carbohydrate volumes, carbohydrate forms, and little-no guidance for healthy fat-based nutrition seems out of sync with endurance-physiology.
Furthermore, specific nutritional recommendations for extreme high-performance, high-intensity world-class (and professional) athletes, may not be the best advice (performance and health) for the realistic training protocols and intensity, of competitive recreational athletes.
While the high-carbohydrate (350-900gr/day, for 75Kg athlete) recommendations suggested by the IOC would hit daily caloric targets, SFuels believes that a more balanced macro-nutrient profile would better serve performance and health outcomes to the competitive recreational athlete. SFuels experience in the successful adoption of this approach by elite athletes has produced multiple world championships, world records, Olympic medals, course-record Ironman and ultra-marathon races.
With low-intensity aerobic exercise being the majority (~70-80%) of an endurance athletes training volume - it's only logical that fat based calories would make-up a more proportionate component of the endurance athletes diet.
SFuels would advocate reaching these caloric loads in an everyday diet, with a more balanced intake of healthy fats (monounsaturated, polyunsaturated, omega3, medium-chain) in addition to material intakes (100-150gr/day) of healthy unprocessed complex-carbohydrates (starchy vegetables, whole grain based foods and low GI fruits), and quality protein (meats, eggs, fish, dairy, cheese etc.)
Clearly carbohydrate ratios would increase in the diet during periods of longer-duration and/or, high-intensity training. It is important that endurance athletes be mindful and deliberate in tuning their caloric intakes relative to shifts in training blocks and seasonal racing demands.
Furthermore, without clear guidance on carbohydrate forms (i.e. complex-starches, nutritional dense, fiber rich), the natural gravity (taste and convenience) would be towards high-sensation, simple-sugar, low-nutritionally dense, low fiber processed foods and drinks. It seems out of place, for the paper supported by IOC, to be recommending the consumption of refined carbohydrate foods like white bread, soft drinks, sugar-jam-honey due to there moderate-high glycemic indexes. Again an elite athlete, training 20-25hours per week, at high-intensities may metabolize such foods. However, the same is likely not true for the recreational competitive athlete training 10-15 hours per week, most of which is at aerobic intensities.
SFuels has been a strong proponent of refueling between workouts, with a wide array of nutritionally dense unprocessed whole foods. In further supporting athletes reaching sufficient caloric targets, SFuels formulates supplemental high-caloric, nutritionally-dense clean ingredient recovery and refueling snacks, like bars, shakes and cereal products.
3) Metabolic-health, micro-nutrient status and bone-mineral density: One of the core factors often referenced in REDs is lowered bone mineral density, and associated risks (stress-fracture etc.).
As noted above, in both training nutrition, and every-day nutrition SFuels is an advocate for all macro food-types including fats, carbohydrates and proteins. While SFuels believes there are both superior performance and health outcomes to athletes practicing the RIGHT FUEL RIGHT TIME principles, SFuels does NOT advocate ketogenic diets for endurance athletes. Besides other reasons for this position, we have noted the mixed findings (1) of ketogenic diets (typically <50gr/day carbohydrate) effecting markers of bone formation and bone density.
SFuels RIGHT FUEL RIGHT TIME principles are modelled to improve metabolic health, notably fat-oxidation efficiency and improved aerobic adaptations. While not the focus or proposed outcome of the RIGHT FUEL RIGHT TIME approach, it is not uncommon that practicing athletes note reductions in body-weight. As multiple research papers would highlight, reductions in body weight from more balanced carbohydrate intake approaches - has has no significant effect to bone turnover (2) or bone health (3). As it relates to calcium absorption in support of bone health, Vitamin D serves a critical function. However, higher body mass index is associated with lower Vitamin D levels, and lower response to supplementation (4). So, lifestyle practices including weight bearing exercise and balanced macro-nutrient intakes that reduce body-mass index, may in fact be beneficial to Vitamin D levels, and bone density.
Practical Athlete Guidance: Sufficient Caloric Intake Practices
1) Three Whole Food Melas per Day: Plan and practice a consistent staple of three (whole food) meals per day - with spread of macro nutrients.
2) Between Meal Snacks: Choose whole foods, or at least packaged whole-food (bars etc.) as in-between-meal snacks. Look for 'high healthy fat', 'high-protein; snacks. Ideas here include, nuts, plain greek yoghurt with berries, whole-grain/nut based cereals, cheeses, fish (Sushi, sardines, canned/smoked salmon, tuna).
2) Macro-Spread in Meals: Plan every meal to include, an array of macro nutrients - healthy fats, carbohydrates and protein. Meals can always be balanced by also incorporating formulated shakes (see below) to offset macro profiles of certain meals.
3) Build Shakes/Smoothies from Quality Proteins & Fats: Ideally, as a base - include quality protein (whey isolate powders, low in lactose), healthy-fats (avocado, walnuts, almonds, cashews, olive oil) in post workout smoothies and shakes. Depending on the intensity-duration of the workout, increase/decrease the amount and type of carbohydrate used in smoothies and shakes. For 1-hour or less low-intensity workouts, you may need little-no carbohydrate in your shake-smoothie. For high-intensity and longer duration workouts add, whole-food dense-carbohydrate based foods (Banana, Berries, strawberry, apple, stone-fruit etc.) to your post-workout shakes.
4) Calcium and Vitamin D: SFuels would advocate for a consistent intake of rich-calcium, and vitamin-D foods, and sunshine skin exposure. Fish, dairy products, green-leafy vegetables all serve as good sources of calcium, and Vitamin D. The NIH recommends for sun-exposure between the hours of 10am to 4pm, for 5 to 30minutes per day on the face, arms, hands and legs.
High-Caloric, and High-Macro Shakes
1) High Protein/Healthy Fat: Blend SFuels Revival Vanilla powder + 1/2 cup full cream, ice and water. 500cal. low-no carbohydrate. 19grams Protein
2) High Protein/Healthy Fat: Blend SFuels Revival Chocolate powder + 1/2 Avocado, Cup whole milk, ice and water. 370cals. low carbohydrate. 19grams Protein
3) High Protein/Healthy Fat/Carbs: Blend SFuels Revival Vanilla powder + 1/2 cup full cream, whole large banana, ice and water. 620cal. 120cals as carbohydrate. 19grams Protein.
4) High Protein/Healthy Fat: Blend SFuels Revival Chocolate powder + Cup blueberries, 1/2 cup full cream, ice and water. 580cals. 80cals as carbohydrate. 19grams Protein
5) Protein/Healthy Fat: Blend 1/3 cup SFuels Grain-Free Cereal, 1/2 cup whole cream, ice and water. 630cals. low carbohydrate. 7Gr Protein.
Hope this helps you stay healthy and delivering consistent high performances through the season. Go Longer. Team SFuels
