Can you eat anything in particular to help 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 is also thought to result in cramping. If you’re worried you may have low magnesium levels, foods such as oats, rye and wheat, as well as mixed nuts and seeds are good sources.
What foods should I be avoiding all together 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 could potentially disrupt bowel function, such as snacks high in fibre and saturated fat.
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 rate from the intestines.
Calcium is important for bone health and three servings a day should provide your recommended daily amount of around 1000mg. 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.
More about dairy-free options to meet your calcium needs
Antioxidants Heavy training increases the production of free radicals which, amongst other things, can lead to muscle damage. Increasing the antioxidant content of your diet at this time can help to scavenge the free radicals, reducing muscle damage, and is believed to alleviate muscle soreness after exercise. Start upping your intake by eating a rainbow of fruit and vegetables in your daily diet.
We’ve heard a lot about beetroot juice – is the hype 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, meaning muscles are more efficient. Although beetroot juice is the predominant choice in scientific studies, other foods naturally rich in nitrate, which might be better suited to your palate, are readily available. Various vegetables are high in nitrate, especially celery, lettuce, leek, spinach, rocket and cabbage.
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.
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.
Fruits 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.
BBC Good Food, Your marathon questions answered [Roxanne Fisher].