Cyclists aiming to improve endurance for longer races such as a century (100 miles) or an Ironman (a triathlon in which the bike leg is 112 miles) will routinely undergo metabolism training rides. These are extended-period workouts – ones lasting upwards of seven hours – that are done at a low intensity. The idea is that your body learns to effectively burn fat as fuel, slowing the rate at which it turns to precious muscle glycogen. The result is a direct improvement in endurance.
For the body to be more efficient at burning fat as fuel, one's intake of healthy fat needs to be adequate. A healthy and easy way to take in enough is to turn to nuts and seeds; raw hemp, flax, or chia seeds; walnuts or almonds are perfect. Eat a total of four to six tablespoons of them spread throughout the day. Raw almond butter is also a good option.