The minimum calorific content of all your nutrition during the race must be at least 25,000 calories. It will be checked before you start.
Most runners store one or two packets of freeze-dried food (hot water is provided at the rest stations) in each drop-off bag in addition to chocolate, gels, nuts, trail mix, energy bars, instant noodles or any non-perishable food items they may chose. It is better to prepare more than not enough. Also, you never know how long you might have to rest at each rest station, so it is better to have more than one freeze dried meal ready, especially for the later stages.
Some runners have even stored fruit in their drop-off bags, but it would have to be packed in container as it will bruise and get damaged during transportation of the drop off bags to the rest station.
Runners should carry whatever food they think gets them through the 30km between rest stations, but remember that 30km at the start of the race in good weather is very different from a 30km at the end of the race when you are exhausted and it is freezing cold.
Prepare the food accordingly, taking into consideration your level of fatigue and the weather conditions, as well as the terrain, when you leave rest stations.
Before the race you will have a chance to visit a local supermarket in Dunhuang, but it has very poor choice compared to any western equivalent!
We strongly recommend brining ALL your food from home. You can purchase soft drinks, chocolate, biscuits, raisins and some nuts in Dunhuang, as well as instant noodles (of rather poor quality) but there are NO freeze dried meals, energy bars, gels or trail mix available in Dunhuang. It is also much cheaper to buy all these products in the West then it is in big cities in China such as Shanghai or Beijing, where they are also not as readily available as in the West.