Read James' answers below then check out our marathon nutrition and training tips, including how to stay hydrated and what to eat when training for a marathon.


Q: Can you eat anything in particular to stop muscle cramps?


James says: There are many potential links to muscle cramping, but there is no single answer or cure. In many cases it appears that muscle fatigue (from increased training) plays a large part. Sodium depletion and dehydration have previously been linked to cramping onset, so it is wise to keep on top of hydration practices. The mineral magnesium helps to maintain normal muscle function, and a deficiency has been linked to cramping. If you’re worried you may have a low magnesium intake, foods such as oats, rye and wheat, as well as mixed nuts and seeds are good sources.

Q: What should I be avoiding altogether when training for a marathon?


James says: Alcohol is the main one to avoid. Also, close to training times, try to steer clear of foods that may cause gut issues, such as snacks high in fibre and saturated fat.

More like this

Q: Are there any other nutrients that are important to the body during training?


James says: Absolutely, some key ones to watch when training are:

Iron plays an important role in transporting oxygen in the blood. During intense training, levels can reduce (especially in females and vegetarians), leading to fatigue. Runners should aim to consume a minimum of two portions of red meat (easily absorbed iron) each week. Vegetarians should ensure plant sources of iron are eaten alongside foods containing vitamin C, to help increase the absorption from the intestines.

Calcium is important for bone health and three servings a day should provide your recommended daily amount of around 700mg. The best-known sources of calcium are from dairy products such as milk, cheese and yogurt, though calcium is also readily available in foods such as fish, green leafy vegetables, nuts, seeds and some fruits and wholegrains. Read more about dairy-free options to meet your calcium needs.

Antioxidants. Heavy training increases the production of free radicals which, among other things, can lead to muscle damage. Increasing the antioxidant content of your diet at this time can help to scavenge the free radicals and may support muscle recovery. Start increasing the variety of fruits and vegetables in your daily intake.

Q: We’ve heard a lot about beetroot juice – is the hype well-founded, and what are the benefits?


James says: In short, yes it is living up to the hype! Beetroot juice contains a component called dietary nitrate. There is increasing evidence that nitrate lowers the energy cost of endurance exercise, to improve performance – although the response is unique to the individual. It’s typically taken 2-3 hours pre-race.Beetroot juice is the predominant choice in scientific studies and is used by athletes. Another way to increase nitrate intake is through nitrate-rich foods, especially celery, lettuce, spinach and rocket.

This would be something to consider only after the basics of fuelling, hydration and recovery are set, as these will have the greatest influence on your performance.

Q: What are the natural alternatives to sports drinks and energy gels?


James says: There are natural alternatives to sports drinks, such as electrolyte drinks (without the carbohydrate). Also electrolytes are present in many foods, so there is no need to use sports nutrition products away from key training sessions or on race day.

Fruit can provide natural alternatives for quick energy, however runners should be mindful of eating such high-fibre options when running, as they may disrupt bowel function.

Are you training for an event this year? Share your tips and experiences below.

James Collins is recognised as a leading performance nutritionist through his work with Olympic and professional sport. Over the last decade he has worked with Arsenal FC, the England and France national football teams and Team GB. He has a private practice in Harley Street where he sees business executives, performing artists and clients from all walks of life. He is the author of the new book The Energy Plan, which focuses on the key principles of fuelling for fitness.


All health content on is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. If you have any concerns about your general health, you should contact your local health care provider. See our website terms and conditions for more information.

Comments, questions and tips

Choose the type of message you'd like to post

Choose the type of message you'd like to post