Nutrition for endurance athletes isn’t complicated, but it’s rather specific. The difference between a strong long run and a workout that falls apart at mile eight often comes down to what you ate, when you ate it, or what you didn’t eat before.

There is a legitimate case for both fasted and fueled cardio, depending on what you are trying to accomplish. Fasted training, typically a workout done first thing in the morning before eating, can improve the body’s ability to use fat as a fuel source over time. For shorter, lower-intensity sessions of 60 minutes or less, many athletes tolerate it well and some prefer it. For anything longer or harder, fueling beforehand is the smarter play. A meal or snack combining easily digestible carbohydrates with a small amount of protein, eaten one to three hours before your workout, gives your muscles the glycogen they need to perform. Oatmeal with banana, toast with peanut butter, or a simple rice-based meal all work well. High fat and high fiber foods before a long effort are worth avoiding. They slow digestion and tend to cause real discomfort once your heart rate climbs.

The most common fueling mistake endurance athletes make is waiting until they feel hungry or depleted to eat something during a workout. By the time those signals arrive, you’re already behind. For efforts lasting longer than 75 to 90 minutes, plan to take in 30 to 60 grams of carbohydrates per hour. Gels, chews, sports drinks, dates, and bananas are all great options. Electrolytes matter as much as the carbohydrates, particularly on hot days. Sodium is the primary electrolyte lost through sweat, and replacing it during long efforts helps you absorb and retain fluid more effectively. An electrolyte drink or tablet alongside your carbohydrate source covers both.

The hour following a hard or long endurance workout is when your muscles are most receptive to rebuilding glycogen stores and beginning the repair process. A meal or snack combining carbohydrates and protein in roughly a 3:1 ratio during this window makes a meaningful difference in how you feel the next day. Chocolate milk, a protein shake with fruit, eggs on toast, or Greek yogurt with granola are just a few good choices. The further you get from that window without eating, the slower the recovery. It doesn’t have to be a full meal, but it has to be something.

Treat nutrition like a training variable, not an afterthought, and your workouts will show it.