The case for eating more
By not fuelling properly, you could slip into the RED-S zone
With concern about weight and obesity so prevalent among the general population, it’s no surprise that we often hear that most people should be eating less, not more. But some athletes, including members of the Lycra crowd, would be well served by stuffing in more pasta, not less.
“In some athletes, there is a mismatch between their calorie intake and the calories they expend during training, leaving inadequate energy available to support the bodily functions necessary for optimal health and performance,” says Hamilton-based sports nutritionist Anne Guzman. This low-energy availability (lea) is a driving factor of relative energy deficit in sport (red-s) syndrome. There is growing evidence that female and male endurance athletes with red-s may experience a variety of consequences. Guzman says they can include inconsistent performance, training plateaus, nagging injuries, poor recovery and loss of muscle strength – nothing conducive to podium finishes and qoms. She adds that those with red-s may also suffer other health issues, such as weakened bones, disruptions in thyroid functioning, poor mental health, impaired immunity, low libido and loss of menstruation in women.
A recent study looking into the energy requirements and intake of six professional male cyclists throughout a weeklong Classics campaign (four one-day races, four rest days) has highlighted the risks of under-fuelling. The investigation published in the Internationaljournal ofsportsphysiologyandperformance found, using data gleaned from food diaries and blood samples, that riders who failed to match their calorie burn with adequate calorie intake during this period had significantly reduced levels of the hormones testosterone and insulin-like growth factor 1, both markers associated with undereating and an elevated risk of red-s. Post-race and in-race carbohydrate intake was insufficient to meet demands. Comparatively, riders who met their energy needs both during race and rest days saw increased levels of the hormones. We common folk can slip into similar patterns during intensive training blocks or while bikepacking, both activities that turn us into calorie-burning machines for several days or weeks.
Generally speaking, an intake of less than 30 calories per kilogram of fat-free mass (kcal/kg ffm) is considered lea among those who train and compete regularly. When athletes are consistently below this level, performance and health implications of under-eating tend to show. “Cyclists who are consciously restricting what they eat with the intent of improving their power-to-weight ratio are at a particular risk for red-s,” notes Guzman. But she adds that sometimes under-fuelling can happen by accident. Maybe during a period of high training loads, you simply have less time for meals. Maybe you’re trying to eat too clean, and end up limiting the intake of calorie-dense foods. Or, maybe you just need to find a better fuelling strategy for your rides. Food consumption can also be influenced by hormonal factors. For instance, a female endurance athlete may experience variations in appetite across a menstrual cycle.
A pair of studies conducted by researchers in Norway and Denmark – one involving male endurance athletes and the other focusing on fit females – found that individuals who spent more time each day in a catabolic state – when calorie intake is not enough to match the metabolic demands of the body – were more likely to have a suppressed resting metabolic rate along with higher levels of the stress hormone cortisol. Males showed signs of reduced testosterone production, while the production of estrogen in females was suppressed. “It’s important to note that being in this situation for one day, or having low-energy intake for just a few days, does not mean you have red-s,” Guzman says. “The habitual behaviour of not fuelling properly is what brings it on and the associated health and performance consequences.”
While lea and red-s can have a significant effect on performance, awareness of these issues remains low. Coaches and athletes should be able to spot the signs of being undernourished, which can include an increase in upper respiratory infections and other illnesses, premature fatigue on rides, bouts of irritability, loss of lean body mass, stress fractures, constipation and menstrual irregularities. Then, they should develop nutrition habits to make sure the engine is properly fuelled each day.