Josh Cox is the U.S. 50k Record Holder, a four-time Olympic Marathon Trials qualifier, and three-time U.S. National Team member. Here's how he trains in his own words:A few years back the Competitor Group sent a film crew up to Mammoth Lakes as part of their Training Day feature. On this day I had a 15-mile tempo on Green Church Road at 7100 feet. Before the workout I took them through my go-to nutrition during long runs, tempos and races (PowerGels mixed in water, typically 1 gel per 4-5oz of water). Check it out here. The first time I attempted the 50k I drank far too much, both in preparation and in race, this led to me being unable to keep the fluids down. The following Outside Magazine Article details that first and my subsequent second attempt where I returned and had much more success (running the second fastest time in history… which sounds so much better than “missed the word record by 7 seconds”). The biggest change the second time was that I approached fueling for the race no differently than I would a marathon. The other major change was in my training; I really focused on getting the fueling in at race pace during my training – for the first time I “trained my gut” and focused on getting in as many calories as possible per hour. This took a lot of practice but the practice paid off. Don’t let nutrition be an afterthought; so many athletes and coaches spend mountains of time preparing their training sessions but fail to address and practice their fueling strategy. In the longer events, particularly anything beyond a 10k, fuel or lack of it, becomes a real weapon – used against you or against the clock. You can follow Josh on Twitter and Facebook @JoshCox.