The Runner’s World Guide to Nutrition and Fueling: Understanding Carbs, Protein, and Fats

As a runner, you may already prioritize carbohydrates—but optimal fueling requires all three macronutrients: carbohydrates, protein, and fat. So, how much do you need of each? Should you be “protein-maxxing?” Can drinking your carbs help you meet your fueling needs? How does your body’s use of fat change across distances? And how should you spread your macros throughout the day?In The Runner’s World Guide to Nutrition & Fueling, an exclusive program hosted by Mireille Siné, our experts answer these questions and more. You’ll learn general guidelines for balancing your macros, plus how to tailor your approach to your training, recovery, and performance needs.What You’ll LearnIn The Runner’s World Guide to Nutrition and Fueling, we’ll teach you:How carbohydrates, protein, and fat fuel your running and recovery How to find the right balance of macronutrients How to estimate your individual macro needs Why your needs change with training volume and intensity How to monitor your intake using objective, subjective, and performance-based feedback Watch VideoGo DeeperCarbohydratesCarbohydrates are your body’s primary source of energy for running and everyday activity. “Think of it like gas in a car,” says Jason Machowsky, MS, RD, CSSD, CEP, CSCS, sports dietitian and clinical exercise physiologist. “Carbohydrates are your body’s fuel to run and feel your best on the run.”How Many Carbohydrates Do Runners Need?Your needs depend on how much you’re running. As a general baseline, aim for at least 3 grams of carbohydrate per kilogram of body weight per day. (To convert your weight from pounds to kilograms, divide it by 2.2.)Weight in pounds ÷ 2.2 = Weight in kilogramsWeight (kg) × 3 = Daily carbs neededFor example, a 150-pound runner weighs about 68 kilograms (150 divided by 2.2) and should aim for at least 204 grams of carbohydrates per day—equivalent to 3 grams per kilogram of body weight (68 multiplied by 3).Your needs may increase during periods of heavier training—and can be double that baseline or more for endurance events such as ultramarathons. The key is to increase your carbohydrate intake as your mileage and training demands rise.Try to include carbohydrates with every meal. If you don’t want to track exactly, divide your plate roughly into thirds:One-third carbohydrates One-third protein One-third colorful fruits and vegetables “The key is that you’re getting in your target amounts and that you’re not displacing other key nutrients for one nutrient that you think you need more of.”– Jason Machowsky, sports dietitian and exercise physiologist Scale your portions as your training changes. “You might need a bigger portion of the plate to be carbs,” Machowsky explains. “Or you might just need to make the plate bigger.”Types of CarbohydratesRefined carbohydrates are typically easier to digest and provide energy quickly, making them useful before or during a workout. Options include:White bread, rice, or pasta Processed/packaged snacks Baked goods and other sweets made with refined flour Complex carbohydrates generally digest more slowly and provide additional nutrients. They’re often a good choice after a run and throughout the rest of the day. Options include:Whole grains Sprouted breads Quinoa Barley Brown rice Carb-Loading Think back to that gas-tank analogy: You want your energy stores to be as full as possible when you reach the starting line.Carb-loading means intentionally increasing your carbohydrate intake before a long-distance event—not just eating an oversized bowl of pasta the night before.How to Carb-Load Strategically:Start with your body weightTake ½ to 1x that numberEat that many extra grams of carbs per dayAdd them to your usual intakeDo this for one to three days heading into your raceFor example, a 150-pound runner would add 75 to 150 grams of carbohydrates—equivalent to one-half to one times their body weight in pounds—to their usual daily intake for one to three days leading up to the race. If they typically consume 300 grams of carbohydrates per day, they would aim for 375 to 450 grams per day.Protein supports recovery after hard workouts by helping your body repair and rebuild muscle, bone, and other tissues. “Your body needs protein to rebuild structures better, faster, and stronger,” Machowsky explains.Your total daily intake matters most, but consuming protein (with carbohydrates) within 30 to 60 minutes after a long run or hard workout can help kick-start recovery. That doesn’t mean the opportunity disappears once that window closes. “Your body continues recovering after,” Machowsky says.Experts recommend spreading protein intake throughout the day rather than consuming most of it at one meal. Aim to include a source of protein at least three times a day.As a general baseline, runners may aim for 1.3 to 1.4 grams of protein per kilogram of body weight per day. For example, a 150-pound runner weighs about 68 kilograms (150 divided by 2.2) and should aim for approximately 89 to 95 grams of protein per day—equivalent to 1.3 to 1.4 grams of protein per kilogram of body weight (68 multiplied by 1.3 to 1.4).1.3 or 1.4 × Weight (kg) = Total grams of protein needed dailyYour needs may increase if you’re also strength training or preparing for longer-distance events.Prioritize whole foods over processed protein snacks when possible. Convenient on-the-go options include:Roasted edamameChickpeasString cheeseMeat sticksCottage cheeseYogurtFatLike carbohydrates and protein, fat is an essential macronutrient. It supports your everyday energy needs, hormonal health, and normal body function. Chronically consuming too little fat may negatively affect hormonal function and recovery.As a general baseline, at least 20 percent of your daily calories should come from fat. This number may go up based on how much you’re training.Sources of healthy fats include:Olive oilAvocadoNuts and seedsFatty fishShould All Runners Be Counting Their Macros?Tracking your food for a few days can provide a useful snapshot of what you’re eating and highlight potential gaps. But you don’t need to count every gram indefinitely—and tracking shouldn’t become obsessive or create an unhealthy relationship with food.Use a short-term food log (one to three days) to establish a baseline. If you identify a gap, make a realistic plan to adjust your daily fueling.You can also evaluate your nutrition using three types of feedback:✅ Objective feedback: Ask about lab work during your annual physical to help identify possible nutritional deficiencies. ✅ Subjective feedback: Keep a wellness log that tracks your energy, sleep, mood, hunger, and recovery.✅ Performance feedback: Look for trends in your pace, strength, and perceived effort. If your performance is declining and you consistently feel sluggish, nutrition may be one factor to examine.Got questions about performance nutrition?Fueling can be the difference between a run that feels strong and one that falls apart.Through conversations with leading sports dietitians, nutrition experts, and coaches, the Runner’s World Guide to Nutrition and Fueling turns the science of sports nutrition into practical, runner-friendly strategies for everyday training and racing. Available exclusively to Runner’s World+ members on September 10!Kristen Wagner joined the Runner’s World and Bicycling team as a senior health & fitness editor in November 2024 with a decade of magazine editorial experience. In her role, she prioritizes content that supports the brands’ marquee video programs and works closely with members on exclusive Train With opportunities. Since joining the team, Kristen has caught the bug for running! She completed her first 5K and looks forward to accomplishing longer race distances. Passionate about all things wellness, Kristen enjoys Pilates and long walks with her dog, Koda. LinkedIn