Q. What Nutrition Should I Eat During Endurance Sports?
A. When you’re depleting your body’s resources through extreme exercise, you need something that will instantly replenish lost glucose, water and minerals to keep you going. Power Bars are excellent for a carbohydrate fix (they also have a good ratio of protein to slow down energy release), or try Multipower protein and energy bars. Zone bars are not bad either, apparently. These are available from most health-food shops.
Two hours before events, you can also boost your glucose stores by eating lots of complex carbohydrates such as fruit, vegetables, wholegrains like wholemeal pasta or rye bread, and baked potatoes. But avoid sugar and refined carbohydrates — they may give you a rush but they will leave you more tired  than you were before.
Ensure you eat enough protein to repair muscles-at least half as much protein as carbohydrates at each meal and snack. So have nuts or seeds with fresh or dried fruit, rice with fish, tofu or lentils, and so on (the combinations arc legion). Remember too that a demanding exercise regime generates more oxidants , so eat plenty of antioxidant-rich foods -go for fruit and vegetables in the Orange, red and blue range, especially berries. 1.5 to 2 liters of water at least, and supplement a high strength multivitamin, 5g of glutamine powder and 2g of extra vitamin C every day before bed to aid muscle recovery .
References:  Frank B Hu. Are refined carbohydrates worse than saturated fat? PMCID: PMC2869506  Elisa Couto Gomes, Albená Nunes Silva, and Marta Rubino de Oliveira. Oxidants, Antioxidants, and the Beneficial Roles of Exercise-Induced Production of Reactive Species. PMCID: PMC3372226  M Khassaf, A McArdle, C Esanu, A Vasilaki, F McArdle, R D Griffiths, D A Brodie, and M J Jackson. Effect of vitamin C supplements on antioxidant defence and stress proteins in human lymphocytes and skeletal muscle. PMCID: PMC2342961