Runners should consume 20-35% (0.5–1.5 g/kg/day) of their daily caloric intake as fat 
. Fats are the predominant fuel during low-intensity runs, and consuming adequate dietary fat is important for maintaining cell membranes, cushioning joints, and insulating organs. Moreover, dietary fats are a vehicle for fat-soluble fats and in some cases, help reduce inflammation and soreness in athletes.
Healthy sources of fats for runners include extra virgin olive oil, nuts, nut butter, avocados, seeds, and fatty fish such as salmon, trout, and sardines.
Eating a well-balanced diet of carbohydrates, protein, and healthy fats is important for runners to improve their adaptive response to exercise 
 Kerksick, C. M., Wilborn, C. D., Roberts, M. D., Smith-Ryan, A., Kleiner, S. M., Jäger, R., Collins, R., Cooke, M., Davis, J. N., Galvan, E., Greenwood, M., Lowery, L. M., Wildman, R., Antonio, J., & Kreider, R. B. (2018). ISSN exercise & sports nutrition review update: research & recommendations. Journal of the International Society of Sports Nutrition, 15(1), 38. https://doi.org/10.1186/s12970-018-0242-y