Okay, okay, so maybe eating spinach won’t cause your muscles the spontaneously burst out of your shirt; nevertheless, there’s compelling evidence to show that spinach has some pretty powerful properties. In particular, research has demonstrated that nitrate containing vegetables, such as spinach or beets, enhance endurance. As a result, if you eat these foods prior to exercising, you may be able to exercise for a longer period of time, without feeling exhausted. How is that possible? Well, it has to do with the fact that the nitrates found in these vegetables, increase your muscle’s uptake of oxygen. In doing so, they enable your muscles to work for longer without becoming exhausted. Hence, the popularity of beet juice among pro-athletes.

—I learned about this fact from: Larsen FJ, Weitzberg E, Lundberg JO, Ekblom B. 2010. Dietary nitrate reduces maximal oxygen consumption while maintaining work performance in maximal exercise. Free Radical Biology & Medicine, 2010, 48:342-347. Bailey SJ, Winyard P, Vanhatalo A, Blackwell JR, DiMenna FJ, Wilkerson DP, Tarr J, Benjamin N, Jones MJ. Dietary nitrate supplementation reduces the O2 cost of low-intensity eBailey SJ, Winyard P, Vanhatalo A, Blackwell JR, DiMenna FJ, Wilkerson DP, Tarr J, Benjamin N, Jones MJ. Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise in humans. J Appl Physiol, 2009, 107:1144-1155. Larsen FJ, Weitzberg E, Lundberg JO, Ekblom B. Effects of dietary nitrate on oxygen cost during exercise. Acta Physiol, 2001, 191:59-66.