What specific nutrient ratios and caloric intake have others found to be most effective for endurance riding, and how did they arrive at those conclusions? What role do macronutrients play in sustained energy production, and how do different types of carbohydrates, proteins, and fats impact performance during prolonged periods of exercise? Are there any particular foods or supplements that have been shown to enhance endurance, and what are the potential drawbacks or risks associated with relying on them? How do individual factors such as body composition, age, and fitness level influence nutritional needs for endurance riding, and what methods can be used to determine optimal nutrition strategies for specific riders? What are the most effective ways to monitor and adjust nutrition plans during training and competition, and how can riders balance the need for optimal nutrition with the practical challenges of fueling during long rides?