Autism and REDs: Why Under-Fueling Doesn’t Always Look the Way We Expect

Tags: Ambassador Experience, Expert Advice, NeurodiversityRead time: 9mins

With special thanks to Project REDs ambassador Millie Watson and Dr Caz Nahman, Child and Adolescent Psychiatrist specialising in eating disorders in athletes and non-athletes, autism spectrum disorder, and compulsive exercise.

There is a version of under-fueling that people tend to recognise in sport. Some athletes might want to lose weight, change their body composition or become “lighter”, so they intentionally restrict what they eat. But low energy availability (and ultimately Relative Energy Deficiency in Sport (REDs)) doesn’t always begin that way.

Sometimes an athlete desperately wants to be healthy, recover properly and perform at their best whatever their body looks like, yet eating enough to consistently meet the demands of sport can still be difficult.

This is an area that Project REDs ambassador Millie Watson is particularly passionate about: improving understanding of the different ways under-fueling, low energy availability and REDS may present in autistic and neurodivergent athletes. The experiences of athletes contacting project REDS suggests not everybody recognizes themselves in a more familiar athlete REDS narrative.

What might autism have to do with fueling?

Autism is extremely heterogeneous with no single “autistic eating pattern” and being autistic does not mean somebody will have difficulties with food. However, feeding and eating differences are more commonly described in autistic population¹.

For an athlete this might mean eating a relatively small number of familiar foods because they are predictable. A particular texture, smell or temperature may make foods difficult to tolerate. A busy dining hall with noise, bright lighting, unfamiliar smells and crowds may make eating far harder.

Some athletes may want to eat more and know they need more fuel but can find the practical and sensory experience of doing so difficult.

Selective eating, ARFID, LEA and REDS are not all the same thing.

• Selective eating: eating a limited or strongly preferred range of foods can result in nutritional impairment.

• ARFID: Avoidant restrictive food intake disorder involves significant food restriction or avoidance with significant nutritional, weight/growth or psychosocial consequences but is not primarily driven by weight or shape concerns.

• LEA & REDS The athlete persistently does not have energy dietary energy available after exercise to support optimal body functions resulting in health and performance consequences.

ARFID and autism do overlap more frequently than we would expect by chance². This does not mean all autistic athletes will struggle to fuel themselves, because autism is incredibly heterogeneous. But it does mean, as ever, that eating enough for sport and eating according to appetite isn't always the whole answer

Sports nutrition advice often tells athletes to “listen to your body” or “eat when your body asks you to”, which for some people, just may not be enough.

Interoception describes our ability to perceive internal bodily signals such as hunger, fullness, thirst, temperature and fatigue. Some autistic individuals describe signals as difficult to recognise or interpret while some signals can be experienced very strongly. Not every autistic athlete will have poor interoception and there are many different profiles that can show up. One person might miss hunger until they have stomach pain, another one could experience stress as stomach pain and find it hard to eat when anxious. Another athlete might become full very quickly so might need to have smaller and more frequent eating.

Sport makes this more complicated as exercise itself can suppress appetite, training schedules can disrupt normal eating opportunities and energy requirements can increase substantially without an equally obvious increase in hunger. Relying only on appetite can sometimes result in unintentionally falling short of what the athlete needs.

When routine helps (and when it doesn’t)

Additionally some autistic people often struggle more what we call “executive function” which again varies between individuals but it means that managing a busy schedule, transitioning between different activities, decision making can all feel like more of an energy sapping burden. One way of managing this is by having strict routines and schedules which are planned ahead of time which reduces this burden. So planning meals, snacks, training in advance reduces anxiety and help an athlete.

The difficulty happens when the body’s energy requireemtns change but the routine does not. AN athlete might comfortably eat the same meals and snacks each day but what happens when weekly training increases from 5 hours a week to weight?

Nothing is being deliberately restricted. There is no desire to lose weight. The athlete may be eating what feels like a perfectly reasonable amount of food. .

This is low energy availability: a mismatch between dietary energy intake and exercise energy expenditure that leaves insufficient energy to optimally support the body's other functions. When it is sufficiently prolonged or severe, the consequences lead to REDs.

Transitions are particularly important

Nutritional deficiencies rarely happen in isolation. An athlete may move to university, change coaches, increase their training load, move into shared accommodation, travel internationally or join a new squad. This can be a the same time as trying to manage academic work, sleep, shopping, cooking, recovery and sports performance.

Dr Caz Nahman, writing for Neurodiverse Sport ³ about coaching autistic athletes described a composite example of an autistic national-level swimmer navigating several major changes at once. Structures that made training and eating and recovery disappeared at the same time that the demands on the athlete increased.

A training camp, university transition, new coach, travel, unfamiliar accommodation or changes to a normal schedule can remove the structures that previously made eating and recovery manageable.For an athlete who relies heavily on predictability, these periods may therefore deserve moreproactive fueling support, not less.

Sport can sometimes hide the problem

This is where things become particularly complicated. Many characteristics that high-performance sport celebrates can look, from the outside, like unequivocally positive behaviours: consistency, repetition, discipline, high training tolerance, sticking to a plan and pushing through discomfort. High performance sport values these characteristics. These may also be genuine strengths for autistic athletes.

Some neurodivergent athletes thrive with clear goals, repetitive skill development, predictability and the opportunity to focus deeply on something important to them. An athlete might appear exceptionally “committed” while finding it extremely difficult to change a training session, take an unexpected rest day, eat an unfamiliar meal while travelling, or add more food when their training increases.

Exercise itself might provide predictability, emotional and sensory regulation or routine, so changing that routine may therefore feel much more difficult than simply being told, “You need a rest day.”

And signs that something isn't right may not necessarily be obvious externally.

Masking:

An athlete may have spent years learning to suppress visible signs of distress, or behave in ways that follow the rules and fit the expectations of people around them.

Communication:

One of Nahman's examples describes a coach failing to recognise an athlete's injury partly because she wasn't displaying pain in the way he expected. An assumption that an athlete will tell the coach when something is wrong can mean difficulties are missed. The athlete might not be deliberately concealing information . Similarly fatigue, anxiety and overwhelm can be missed until they became much more extreme.

There is an obvious lesson here for REDs too: absence of obvious distress is not necessarily evidence that an athlete is coping well.

An athlete striving to be the best, can follow sporting instructions very loyally – “eat clean”, “train as hard as possible”, “don’t miss sessions “, “know your limits”.

A coach who gets to know their athlete can be helpful with the precision and flexibility around information. "If you get this pain, stop and tell me. Today’s session is a recovery session not about improvement”.

Autism does not cause REDs

Being autistic does not mean an athlete will develop REDs, and neurodivergence should never be pathologised simply because somebody eats, communicates or structures their life differently.

There is also currently very limited research specifically examining autism and REDs in athletic populations, so we cannot say that autism itself is an established REDs risk factor. What we can say is that characteristics described in autism research, including sensory-related eating difficulties, food selectivity, reliance on familiar foods, differences around routine and, for some people, differences in recognising internal cues, could interact with the exceptionally high and constantly changing energy demands of sport.

Likewise, sporting environments that reward repetition, persistence and pushing through discomfort may sometimes make an emerging problem harder to spot.

How to help an autistic athlete?

Nahman’s recommendations for coaches/supporters emphasise clear communication, making implicit expectations explicit, explaining the purpose of sessions and treating recovery and self-care as genuine parts of athletic development. For one individual, predictable meals and snacks built into the training day can be important rather than relying on hunger. For another, they might need access to familiar foods and snacks with opportunity for a quiet place to eat. A written fueling plan and advance warning of schedule changes might be important to support the athlete.

Coach messaging around commitment to training, how much pain and fatigue should an athlete push through (or not), how intense the athlete should train in a particular session, requires nuance as extreme rules that are followed can be harmful. Similarly rules around “healthy “ eating can result in rigid food rules that can mean inadvertent restricted eating.

Support staff may need to actively check in with their athlete, rather than always relying on the athlete to recognize a difficulty and to know when to report this.

And where eating is significantly restricted or difficult, support from appropriately qualified professionals, potentially including a sports dietitian and clinicians familiar with autism, eating difficulties or ARFID, will be important. Adjusting to the individuals food preferences and sensory preferences and pacing change and explaining the science behind REDS recovery will help athlete buy in and commitment.

Crucially, the aim is to work with the autistic athlete’s strengths and to individualise approaches and work with them to help them meet their nutritional, recovery and health needs.

We need to widen the REDs conversation

REDs education has progressed enormously, but our mental picture of an athlete at risk can still be too narrow. Not every athlete with REDs is trying to become thinner, or under-fuel intentionally. Not every athlete who appears highly disciplined is necessarily thriving, and not every athlete who struggles with food needs the same intervention.

If coaches, parents and practitioners only look for visible weight loss, body dissatisfaction or intentional restriction, we risk overlooking athletes whose pathway into low energy availability looks entirely different.

Understanding autism is one part of widening that picture.

As Millie Watson and others within the autism community continue to highlight, there is a real need for more research and education at the intersection of autism, neurodivergence, nutrition and sport.

Because the better we understand the different pathways that can lead to low energy availability, the earlier we can recognise when an athlete is struggling and the more effectively and compassionately we can support them.

If there is one thing we know about REDs, it is that it certainly doesn't have a “look”.