I need some advice! This Sunday I’m supposed to do my longest run ever: 17 miles. Based on my last long slow training run, this is going to take me just shy of four hours. So I’m thinking hard about nutrition. I’m aiming to get around 75g of carbs per hour (eating every 15 minutes starting from the 45:00 mark). I’m planning to use a combination of energy gels and gummy bears for that. The other crucial issue is sa…