Clinical & Performance Sports Nutrition for Athletes

Perhaps you have tried supplements, elimination diets, online advice, blood tests, food tracking or simply telling yourself you should put up with the symptoms, thoughts or behaviours. Yet you still do not know what is driving the symptoms, why performance has changed, why your body feels under pressure, what is safe and appropriate for you, or where to start.

Maybe you have reached out for support before, but not felt that there was enough time, depth or personalisation to understand your full picture.

A generic plan is not enough when REDs, eating disorders, disordered eating, gut symptoms or medical conditions are involved. The Problem Is Rarely Just Food

“Just tell me what to eat” can feel like the quickest solution.
But when health, fuelling, symptoms, behaviours, thoughts and performance are connected, a food list will not give you the full answer.

Your nutrition strategy needs to consider your physiology, medical history, symptoms, blood markers, training load, recovery, relationship with food and the realities of your life.

At 4th Discipline, we bring those pieces together to identify what may be limiting your health, fuelling, recovery or performance.

The aim is definitely not to create another set of rigid rules.

It is to help you understand your symptoms, behaviours and what your body may be trying to show you, then build a safe, personalised strategy that supports your health, confidence and long-term performance.

Could Training Feel More Consistent Again?
Think about training without constantly wondering whether your body has enough energy to adapt, recover and perform. For athletes recovering from REDs or an eating disorder, this is about rebuilding trust, supporting hormones, bone health, recovery, strength and longevity in sport.

Could Food Feel Less Overwhelming?
Picture a time where food takes up less space in your head. Meals no longer feel like something to earn, control, compensate for or fear. Eating out, travelling, fuelling training or eating with friends feels possible again.

Could Symptoms Stop Dictating Your Life?
Envisage knowing how to manage gut symptoms with more confidence. You understand what may trigger discomfort, when nutrition can help and when further clinical support or testing may be appropriate.

Could You Feel More in the Driving Seat?
Imagine knowing what to eat to support your condition, your health and your performance. You understand the reason behind the advice, and your decisions around food feel clearer and less reactive.

Symptoms, food anxiety or under-fuelling do not have to take up so much of your life. With the right expertise, support and strategy, it is possible to rebuild trust in your body, make clearer decisions around food and start feeling well again.

Health Is the Foundation Real Performance Is Built On

In REDs, low energy availability can affect reproductive, bone, immune, metabolic, cardiovascular, gastrointestinal and psychological function (Mountjoy et al., 2023). Being lighter is not necessarily faster or healthier. The value is knowing when fuelling, symptoms or behaviours are starting to compromise the body’s ability to keep performing.

Eating Disorders are rarely about food

Eating disorders are more common in elite athletes than many people realise, with one study reporting subclinical or clinical eating disorders in 13.5% of elite athletes compared with 4.6% of controls (Sundgot-Borgen and Torstveit, 2004). Restoring healthier eating patterns can support sleep quality, focus, emotional health and long-term performance (National Eating Disorders Association, 2023).

Symptoms Can Cost More Than Comfort

When IBS symptoms cause up to 10% of work hours to be lost, this is not just discomfort; it can affect focus, productivity and professional performance (Wilkins et al., 2012). Poorly managed nutrition in IBS or IBD can also contribute to fatigue, absenteeism and reduced productivity.

A Diet Plan or Food Lists are Not the Same as Clinical Guidance.

“Just tell me what to eat” might seem like a quick fix, but it is not sustainable. Without understanding your condition, symptoms, blood markers, recovery and relationship with food, it is difficult to build the skills and confidence to take control of your health.

As Clinical Director of 4th Discipline, I bring together more than 23 years of clinical nutrition, elite sport and high-performance fuelling experience.

My work sits at the intersection of clinical nutrition, sports medicine and performance. I have supported people with complex nutrition needs across gastroenterology, diabetes, renal, liver, cardiology, orthopaedics, eating disorders, disordered eating and REDs.

I work with athletes, driven professionals, elite performance pathways and world-class programmes, often collaborating with medical, coaching and sports-science teams to support joined-up care.

As a Registered Clinical Dietitian and High-Performance Sports Nutritionist, I look beyond food alone. I consider the clinical picture, the sporting demands and the person in front of me.

That is why I describe myself as a Nutritional Engineer.

I connect the clinical and sporting data, then build a personalised strategy around you, not a generic plan.

1:1 Personal Performance Nutrition Coaching

Understand Where You Are Now

Begin with an in-depth assessment of your nutrition, health, medical history, symptoms, blood biomarkers, eating patterns, training, recovery, injury history and relevant performance data. The aim is to understand what symptoms and clinical markers may be limiting your health, fuelling, recovery, confidence or performance.

Set Clear Health and Performance Goals

Define meaningful goals across health, training, work, recovery and daily life. This may include reducing symptoms, improving energy, supporting eating disorder recovery, addressing low energy availability, rebuilding fuelling confidence, improving gut tolerance, supporting blood markers, reducing injury risk or returning to training safely.

Enhance Knowledge and Regain Confidence

Develop the tools and skills to make informed nutrition decisions around your health, symptoms, training, recovery, travel, social life and performance. This may include understanding REDs, energy availability, eating disorder recovery, gut health, fuelling for training, hydration, micronutrients, blood markers, meal structure, food flexibility , intuitive eating and symptom management.

Identify Marginal Gains

Explore the smaller, personalised changes that can improve energy, symptoms, recovery, resilience, confidence and performance. This may include meal timing, snack structure, fuelling around training, gut tolerance, hydration, recovery nutrition, food variety, fibre tolerance, sleep support, social eating and travel strategies, or small steps towards food flexibility.

Test, Review and Adapt

Use regular coaching and professional interpretation to assess what is working, respond to challenges and refine your strategy over time. This is particularly important when symptoms change, training load increases, recovery is inconsistent, medical treatment changes, confidence around food fluctuates or eating disorder thoughts become stronger.

Create Lasting Performance Habits

Build routines and systems that support consistency during demanding work periods, heavy training blocks, travel, injury, illness, recovery and life transitions. For eating disorders, disordered eating or REDs, this may also include relapse prevention planning, recognising early warning signs, identifying triggers, strengthening your support crew and knowing when to reach out for additional help.

24:7 Learning Lab Access

Gain access to performance guides, recipes, educational videos and on-demand learning resources to support your nutrition knowledge between sessions. Resources can be used alongside your personalised support to help you understand your body, your condition and the practical steps that support progress.

Speak With Claire

Choose Support That Fits Your Situation

Eating Disorders

Clinical support tailored to the individual, meeting you where you are right now and agreeing how to start the journey. Support may include working alongside other healthcare professionals where appropriate.

Eating Disorder Support

REDs

Clinical and sports performance support to understand fuelling, training load, injury patterns, competition pressures and recovery timelines.

REDs Support

Clinical Conditions and Symptoms

Personalised advice for IBS, IBD, coeliac disease, diabetes and complex gastrointestinal symptoms.

Clinical Nutrition Support

“I run better, I feel better, I’m not getting injured, and I sleep well”. “I thought I needed a diet plan; but that is exactly what I didn’t need. I gained the knowledge and support and the balancing of everyday life around training along with personal life too”.

~ Sam Lt Cdr Thompson MBE RN, Senior Naval Instructor Wildcat Training Centre, and Ironman Age Group Triathlete

“ frankly i hadn’t got any knowledge….Claire was amazing! She helped me plan out my nutrition… to make sure i was getting the best performance (this) allowed me to fully concentrate on the competition.. “best competitive season of my life so far, gaining my first GB senior vest competing at the Athletics World Cup, 2nd place at the British Championships and becoming England Champion gaining my first England Senior International vest”

~ Sophie Physiotherapist and GB pole vaulter

I was a relatively competitive athlete but wasn’t getting any better. My relationship with food was challenged, but Claire Fudge unzipped all of my psychological hang-ups and addressed it with science. It freed me from worrying, and I actually started enjoying food again. It’s an educational investment, a change-in-whole approach, and something I will carry through for life. I can’t recommend her highly enough.

~ Richard CFO and Ironman Age Group Athlete

I have worked with Claire for over a year having suffered with disordered eating from an early age. I knew I needed to do something to change it.

~ Annie Business professional and Runner

I went to visit Claire for a sweat test. This was really useful and informative experience and Claire is very knowledgeable and helpful.

~ Jeffrey

“revolutionised how I eat during …. big sessions. From my former race snacks mindset to a proper fuelling strategy-it’s made a demonstrable difference in my form”

~ Andrew Managing director and Triathlete

instrumental in uncovering my coeliac disease, supporting me to make the necessary changes to a gluten-free lifestyle, which alleviated by IBS symptoms. This in turn positively impacted my fertility. Can’t thank her enough for her tailored expertise which also extended to advice around diabetes management during pregnancy!

~ Jen Psychologist and Yoga

“ I could write so much more . Claire has done an amazing job, and been great, provided consistent, caring support along a tough path to improve my nutrition and expert, individualised advice for fuelling (…) Claire is so well informed, not only in sports nutrition and supplements but also (…) in other areas, including sleep; protein, and ageing (in the context of) a healthy balanced nutritious diet to meet daily and training needs. I have learnt so much and feel so much more equipped to fuel”

~ Mary R. Doctor and Ironman Age Group triathlete and Endurance Athlete

“exceptionally supportive …excellent knowledge of nutrition both in terms of supporting sports performance but also in optimising health. Claire’s background in long distance triathlon herself means that she is able to support in ways others wouldn’t …..her race and training experiences. I (would) recommend Claire for anyone who is looking for support with their nutrition – either for optimising everyday health and wellness or for enhancing and supporting sports performance”

~ Julia Business professional and Ironman triathlete

I really enjoyed the discussions with Claire. She gave me really good and relevant advice which helped me a lot to overcome my problem.

~ Anonymous Business professional

A friend who is a no nonsense athlete was working with Claire and I thought she would be good for me as although not a ‘real’ athlete myself, I wanted to understand how to fuel for 70.3 training and simultaneously sort out my ongoing chaotic relationship with food and eating for ‘normal life’. I knew Claire had an understanding of and worked in both areas.

~ Penny Teacher and Triathlete and cyclist

Struggling with allergies, intolerenaces and anxiety around food for many years had a huge umpact in my daily life, being able to properly fuel for marathon training, recovery and race days. Symptoms have improved dramatically, my training is much more efficient and my confiedence around food has grown. I have lost count of the different diets and plans that I have tried; I have seen a really positive change. I really couldn’t recommend Claire any more highly.

~ Rhys Accountant and Marathon runner

The moment someone says to you, ‘you know the symptoms you are experiencing are not normal’. Was really the moment the journey began to experiencing a normal existence. “years with food intolerances, …. impossible to control …..I am now free to live my life without symptoms and all of the related issues I was experiencing (anxiety about going places, worrying if I was going to be ill when I went out, the list continues…) . all of the guesswork (was removed) ….introducing each element in bitesize chunks ensured it wasn’t in anyway daunting, and allowed the outcome to be obvious . Having the support and expertise throughout was such a huge benefit, and now I can everyday apply the principles learnt with confidence, knowing they are specific to my needs. Being normal feels amazing!”

~ Sarah Director and Adventure Endurance Cyclist

Just wanted to email you with a big thank you for helping me to manage my eating regime. I was very pleased with my race results.

~ MS Business professional and Runner

I had a sweat test done by Claire – I’ve yet to put the results into practice, but really enjoyed our discussion. She explained the process and how to put the results into practice very clearly. She also seemed to me to have a very balanced view (it was not just a sales pitch for Precision Hydration!) which gave me a lot of confidence in her advice.

~ Kevin

Just wanted to email you with a big thank you for helping me to manage my eating regime. I was very pleased with my race results.

~ Anonymous Athlete

Claire challenged my unhealthy food beliefs in an empathic manner and suggested changes that were specific and achievable whilst continuing in my recovery from anorexia. “her knowledge and support have been really valuable in the progress I have made over the past few months and I would definitely seek her advice in the future.

~ S Business Professional

I’ve learned so much stuff I didn’t even know existed, different types of proteins, when to take, when to take dairy, how to stay full, what’s a good probiotic to boost my immune system…I’m always learning, I think I’ve really improved” . –

~ Morgan Pearson Professional Triathlete USA and Double Olympic Silver Medalist

claire challenged my unhealthy food beliefs in an empathic manner and suggested changes that were specific and achievable whilst continuing in my recovery from anorexia. “her knowledge and support have been really valuable in the progress I have made over

~ Steph Runner

Where I’ve really benefited from working with Claire Fudge is around the timing of food around my training, but also particularly around travel. Working with Claire on a plan so that I don’t go for chocolate in the airport or at the petrol station, but have snacks and planned timing along the way has really been beneficial. She’s great at delivering helpful tips that are quick and easy to do.

~ Laura Siddall Professional British Triathlete

I wanted to understand what food is good for me as I trained and when doing races…..some foods did not agree with me but I did not understand why……..Gave me these answers and has helped me improve my race times as well as eat more sensibly. My lifestyle has benefited from this enormously. I received expert advice on what to eat during (injury) ….incredibly helpful and informative and I was impressed at her wealth of knowledge & experience. “Claire helped me understand what foods work for my body. I’ve improved my race times and transformed my lifestyle.”

~ Rachel Managing director and World-class triathlete

I started working with Claire when I realised that I thought I knew what I was doing but I really didn’t when it came to sports nutrition. I’d been competing at an age group level internationally in triathlon and since working together, my performances have improved together with making podium places as well as making the jump up to 70.3 a successful one.

~ Jess Doctor and World-class Ironman athlete

“I thought I needed a diet plan; but that is exactly what I didn’t need. I gained the knowledge and support and the balancing of everyday life around training along with personal life too”.

~ Steph Business owner and Triathlete

“I could start to eat intuitively again; I recovered my menstrual cycle and eat intuitively without any fear; she was there with support and guidance”

~ Ella Runner

Great first meeting and assessment with Claire. A huge amount to take in but Claire guided me through the first stage. Have some clear first steps to work on in my journey to improving my hydration and nutrition to support improved training and race performances.

~ Giles C. Finance Director – Retired and Ironman Age Group Athlete

“You quite literally changed my life; I could not have done this without you”

~ Charlie R. Business Owner, Entrepreneur, and Ironman and Endurance Age Group Athlete

Thank you for your help over the last few months. It was very helpful and I learnt many things I was not aware of before.

~ Giulia Runner

“help with a long standing issue, It was her personality, honesty and openness which gave comfort in trying her methods. Over the year that I have spent working with her, I have gained the knowledge and insight to manage my symptoms, giving me a new found sense of freedom. I would wholeheartedly recommend Claire to anyone who needs nutritional advice.”

~ Richard Business owner and Triathlete

I couldn not recommend working with Claire enough – it was a relef to find someone that could relate and understand my nutritional needs for ironman training/racing and recovery!

~ Emily Business professional and Ironman triathlete

“Your encouragement means a lot at a time when work and training is difficult and I cannot see the journey back to ‘normal’….. your positivity is highly contagious – I feel better already “

~ Caroline Business professional and Triathlete

The work we have done together has covered race day nutrition, everyday nutrition, and has helped me have a better relationship with food. So often we have coaches for the sports we do, yet no guidance or coaching when it comes to nutrition. Working with Claire has really helped up my performance. Thanks to Claire and Fourth Discipline for all the continued support.

~ Allysha Krall Triathlon Coach and USA Pro Triathlete

I’ve been running for quite a few years, but I just kept running out of energy. Training for a marathon, I got in touch with Claire. I thought she would just give me a food plan, but she basically educated me on what I needed to eat and the right food groups to eat together. It was just an absolute game changer. I did my marathon with absolutely no problems—didn’t once run out of energy.

~ Joanne Managing Director and Athlete

In Claire, I have found a dietitian who not only is a specialist in nutrition, but also really understands the specific demands of an athlete. She acknowledges that one size does not fit all and really considers all the different aspects in optimizing nutrition for me as an individual. Most importantly, she helps me understand every little step of the process so that I know how to fuel myself even when she’s not around.

~ Sabrina Stadelmann Economist and Professional Swiss Triathlete

“Claire’s methods didn’t leave me feeling hungry or depleted of energy like fad diets can, in fact I couldn’t quite understand how I was able to eat quite so much and feel so full and strong………what a difference having a nutrition plan to work with made. My performance rocketed and I completed my two dreams in one season. Medalling at the European Middle Distance AG triathlon and smashing my first ironman”

~ Toni Director and Triathlete

I first met Claire Fudge of 4th Discipline in the summer of 2021 for sweat rate test to better understand his electrolyte and hydration requirements for training for a Guinness World Record attempt for an endurance event.
I came away thinking I would like to work with the 4thdiscipline team as they provide nutrition coaching for performance to professional athletes and people like me who have been blundering through the nutritional needs of heavy training.
4thdiscipline know their stuff and their engagement with me was focussed on my individual needs basing my education and planning on science. At all times they worked with me in a calm, supportive and realistic fashion.
For anyone looking to improve their understanding and knowledge of food and sport I can highly recommend them!

~ Seamus IT consultant and Squash

Which service is right for me?

Do you only work with professional and elite athletes?

What is Personal Performance Precision?

Personal Performance Precision is my approach to creating nutrition support that is fit for purpose and designed around the individual.

Generic plans are built for an average person. They do not account for your physiology, health history, symptoms, training, workload, lifestyle, preferences or goals.

Personal Performance Precision brings these factors together with clinical expertise, performance science and meaningful personal data. This allows us to identify what is affecting your health and performance, then engineer a practical strategy around your specific needs.

Like a tailored suit rather than something taken straight from the rack, the strategy is shaped around you: how you live, how you move, what your body needs and what you are working towards.

The result is not simply more nutrition information. It is a clear, personalised approach designed to support your energy, health, recovery and performance now and over the longer term.

What is the difference between a dietitian, a nutritionist and a nutritional therapist?

In the UK, dietitian is a legally protected title. Dietitians are regulated healthcare professionals qualified to assess and treat nutritional problems, including those associated with medical conditions.

The titles nutritionist and nutritional therapist are not legally protected, so qualifications, training and experience can vary. Registered Nutritionists and nutritional therapists who belong to recognised professional bodies may have completed relevant training, but their scope of practice differs from that of a registered dietitian.

As a Registered Clinical Dietitian and High-Performance Nutritionist, I combine clinical assessment and evidence-based care with specialist sports and performance nutrition.

This is particularly important where symptoms, blood markers, low energy availability, gut issues, injury, REDs, disordered eating or a medical condition may be affecting health and performance.

Do you work with people with eating disorders or REDs?

Yes. I provide specialist clinical and performance nutrition support for athletes and active individuals with eating disorders, disordered eating, Relative Energy Deficiency in Sport (REDs) and low energy availability.

Support may include nutritional rehabilitation, restoring adequate fuelling, reducing nutrition-related risk, supporting training and recovery, and working alongside doctors, psychologists, physiotherapists, coaches and other members of the multidisciplinary team where appropriate.

Where clinical risk is present, the priority is always safe, coordinated and appropriate care.

Do you write meal plans or diet plans?

A clear plan for what, when and how you eat can be valuable, but lasting change requires more than a prescriptive meal plan.

Where appropriate, I provide personalised meal structures, fuelling plans, practical food ideas, competition strategies and guidance around timing, recovery and preparation.

These sit within a wider approach that considers your health, schedule, training, travel, preferences, symptoms and goals.

The aim is to give you a strategy you can understand, adapt and sustain rather than a rigid plan that only works temporarily.

Do you offer one-off consultations?

Most individual support is delivered through a structured programme rather than a single appointment.

A first consultation begins the process of understanding your symptoms, patterns, data, health history, training demands and goals. Follow-up support allows recommendations to be implemented, reviewed and refined.

One-off specialist consultations may be available for clearly defined needs, such as an expert review or sweat sodium testing.

Please contact the team to discuss the most appropriate option.

What happens after I enquire?

You will be guided towards the service that best matches your goals, health needs and performance demands.

Where appropriate, the first step will be a discovery call or initial conversation to understand the support you are looking for and whether the service is the right fit.

You will then receive clear information about the recommended pathway, what is included, the expected timescale and the investment required.

A limited number of new clients are accepted each month to maintain the depth and quality of personalised support.

Do you work with other health care professionals in eating disorders ?

Why see a dietitian when you have an eating disorder or REDs ?

Do you only work with athletes with REDs or Eating disorders?

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Clinical & Performance Sports Nutrition for Athletes

Clinical & Performance Sports Nutrition for Athletes

1:1 Performance Nutrition Support

When Health, Food and Symptoms Start to Feel Complicated

Are You Working Hard but Not Recovering Well?

Has Food Started Taking Up Too Much Space?

Are Symptoms Dictating Your Training and Life?

Do You Have More Questions Than Answers?

Could Health, Food and Performance Feel Different?