The Ironman Diet

The Ironman Triathlon is an infamous long-distance race organised by the World Triathlon Corporation. It consists of a 2.4 mile (3.9km) swim, 112 mile (180km) bike ride and a 26.2 mile (42.2km) run. Triathlons necessitate an unwavering level of dedication (particularly if you want to participate in ironman events) which spans not only gruelling training sessions but also making a healthy, balanced diet part of your lifestyle.

If a functional, well proportioned, lean muscular physique is your aim, then I would recommend triathlon training. It is the perfect balance of endurance, power and speed and if you are looking to push to the limit, it is extremely rewarding.

Ironman athletes train 12-20 hours a week! If you want to succeed in this event, it is not a part-time feat. It can be difficult to gain all the requirements you need through diet, but with a better knowledge of what to eat and when, it can become much easier.

The first issue with training of this magnitude is correctly estimating your energy demands. Most people tend to underestimate the calories that a workout of this nature requires. When you think of the extra energy you will require for mechanical movement, you probably haven’t even considered that the impact of running on lower limbs and recovery from each training session will also require more energy.

Your daily intake should be divided as follows; 60% carbohydrates, 20% lean protein and 20% healthy fats. The carbohydrates you consume should be from sources such as fruit, vegetables and whole grains. Doubling up the amount of meals you daily is a better option than piling up your plate in one sitting in a bid to increase calorie intake. A massive portion is likely to make you feel sluggish and cause problems when you come to train.

The focus on carbohydrates for endurance athletes tends to make them neglect their protein and fat requirements. Low dietary protein will increase muscle recovery time and have a detrimental impact on training. It is also more likely that you will suffer from fatigue and anaemia thus undoing all your hard work in training. 1.4-1.7g per kg of body weight is recommended for endurance athletes. I would recommend that you stay at the upper end of this if you are training for an event of this magnitude. The use of protein shakes, particularly post-workout, is an extremely good idea when you are training at a high intensity day after day. Although we would usually associate protein supplementation with strength and power athletes, it is also highly important to an endurance athlete.

Hydration is highly important to ironman athletes. As you are not able to intake fluids during the swimming portion of your event, it is vital that you keep fluid and electrolyte levels as optimum as possible before and after this section. Do not include caffeinated beverages in your fluid count and try to avoid them when you are not training. They act as a diuretic and will cause you to become dehydrated if you do not use them effectively. The intake of water is vital to the chemical reactions that occur in the body to utilise energy, aid muscle repair and prevent damage to cardiovascular, skeletal and digestive systems. Opt for an isotonic sports drink when training exceeds 90 minutes to help replenish electrolytes and fluid lost through sweat.

Foods to focus on:

Lean Red Meat – The amino acids will help aid muscle damage and the zinc will ward of infection. The iron in red meat is more easily absorbed by the body than from alternative sources and will help guard against anaemia.

Vegetables – A great source of vitamins and carbohydrates! Load up on carrots as the carotenoids help boost immunity and protect cells from free radical damage.

Eggs – An excellent source of protein and vitamin K.

Potato – Though many people avoid these when eating a healthy diet, they are a great source of fibre, vitamin C and of course, carbohydrate. They are easy to digest which makes them great for pre or post-training meals.

Quinoa – This relatively unknown superfood is a great alternative to pasta or rice. It is high in protein and is an excellent source of magnesium, iron and dietary fibre.

Walnuts - a great snack to include in your diet as they contain high levels of omega 3. Omega 3 is a fatty acid which the body cannot make itself but is necessary to the upkeep of your body. It plays a role in inflammation reduction and lowers LDL (bad) cholesterol.

Salt Tablets – These will aid fluid retention helping you to avoid inconvenient trips to the toilet during mammoth training sessions and ensure your sodium and potassium levels remain normal.



Applegate E, Effective Nutritional Ergogenic Aids, International Journal of Sports Nutrition, 1999, 9:229-39.

Maximising triathlon performance: a multi-disciplinary perspective, 1999.

About the Author

Job Role Sports Nutritionist and Social Media Coordinator Qualifications Bsc Sport and Exercise Science Steph has a competitive athletic background which spans 19 years. As a child she performed with the English Youth Ballet and had performed on the West End stage by the age of 10. Her enthusiasm for sport and fitness continued to grow as she did, encouraging her to learn more about nutrition and training. She began using her knowledge and personal experience to help others when she began coaching at the age of 16. From here, she went on to study Sport and Exercise Science at the University of Essex during which time she also received the Most Promising Newcomer Award from her University to mark her outstanding contribution to sport. During her first year of study she was introduced to partner stunt acrobatics and artistic gymnastics. After one year of dedicating herself to a lifestyle revolving around her sport, she was training with the best team in the UK who are currently ranked fifth in the world. Steph has worked in both the private and public sector coaching children and adults from grassroot to elite level as well as providing them with cutting edge advice on how to reach their goals. Steph has received awards for her choreography and has competed nationally and internationally meaning that she can back up her scientific knowledge with a wealth of experience. As our resident Sports Nutritionist, Steph is here to provide the most current and evidence based fitness, health and nutrition information to help you reach your health and fitness goals.
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