The ultramarathon is defined as an event whose distance is greater than a marathon. It requires not only a preparation on the endurance performance, but also of other more specific qualities such as orientation and climbing. This type of event has a minimum duration of 5 h up to 22 consecutive days or more. These characteristics influence in the preponderance of the energy system and consequently which nutrients will be necessary to intake and increase in order to replace them.The adequate nutritional planning is a fundamental tool to optimize the athlete's performance, replenishing nutrients and electrolytes and reducing fatigue during exerciseThe aim of the review is to determine dietary guidelines in continuous ultramarathons. The energy, macronutrient, vitamin, and mineral requirements will be increased according to the intensity and duration of the ultramarathon. The energy expenditure ranges from 350-650 kcal/h, determining a negative balance. The role of carbohydrates for its rapid energy replenishment and the role of lipids for multi-day events are distinguished. The recommendation of carbohydrates is 7-12 g/kg in order to achieve muscle glycogen repletion. Protein intake is 1.2-1.7 g/kg to prevent muscle damage and/or used it as an energy source in case of a poor energy supply. Hydration is crucial in prolonged events and especially in warm environments.Once the systematic review of nutritional guidelines in continuous ultra-marathon events has been performed, it has been found that athletes fail to meet nutritional and water recommendations. The cause of this fact is multifactorial (e.g., high energy depletions, inability to carry the totality of food with them, tiredness of the same flavors, hot environmental conditions..), but mainly due to gastrointestinal discomfort and lack of appetite. It is important to provide runners with not only accurate nutritional guidelines, but the correct way to accomplish them to finish the event and to prevent episodes that compromise their health.