How much do runners actually need?

There is no single correct number for every runner. Your needs move with your training, your body size, your goals, and even your week. Think of the ranges below as grounded starting points to personalize, not strict rules to obey.

Daily carbs, protein, and fat — and why your number shifts week to week

Carbohydrate needs scale with how much you run. On easy or rest days, you need less. During heavy weeks with long runs and hard workouts, you need more to keep glycogen topped off. This is why a fixed daily carb target rarely fits a real training block, and why matching your intake to your training tends to work better.

Protein needs for active people generally sit around 1.4 to 2.0 grams per kilogram of body weight per day, according to the International Society of Sports Nutrition. For a 68-kilogram (150-pound) runner, that is roughly 95 to 135 grams a day. Spreading it across three or four meals is a practical way to get there.

Fat generally fills the remaining share of your calories once carbs and protein are set. There is no need to fear it or to overdo it. The bigger point is that these numbers shift week to week, and eating enough overall is what keeps the whole system running.

“When a runner tells me they think they shouldn’t eat carbs, I remind them that carbs are the fuel their legs run on, not something to earn or avoid. We build meals around their training week so they have energy for the miles and recover well after. In my experience, eating enough carbohydrates consistently is what helps runners feel strong and steady rather than depleted.” — Bridget Isaacs, MS, RD

When “eating enough” is the real problem (under-fueling and low energy availability)

For many runners, the issue is not eating too much. It is eating too little to recover well. When you consistently take in less energy than your training and daily life require, you can enter a state called low energy availability.

Under-fueling can be quiet at first, then costly. You may notice nagging fatigue, poor sleep, frequent illness, stalled progress, injury, mood changes, or, for some people, changes to their menstrual cycle. These are signals worth taking seriously, not pushing through.

If any of that sounds familiar, the fix is usually more food and better timing, not more discipline. This is a supportive, solvable problem, and it is one a registered dietitian who works in sport nutrition can help you untangle without guilt or guesswork.

What to eat before a run

The right pre-run food depends on how much time you have and how hard you are about to work. The general aim is to top off energy with easy-to-digest carbs while keeping your stomach comfortable. What settles well is personal, so treat the guidance below as a starting point to test in training.

The full meal: 2 to 3 hours before

When you have a few hours before a longer or harder run, a full meal built around carbs works well. Include a moderate amount of protein, and keep fat and heavy fiber lighter so digestion has time to settle. This gives your body time to turn food into usable fuel.

Practical examples include oatmeal with banana and a little peanut butter, toast with eggs, or rice with chicken and vegetables. Aim to finish eating with enough lead time that you feel fueled but not full. Two to three hours is a common window, though some runners need a bit more or less.

The quick snack: 30 to 60 minutes before

When a run is close, go smaller and simpler. A carb-focused snack that is low in fat and fiber tops off energy without weighing you down. Think a banana, a slice of toast with honey, a handful of pretzels, or a small bowl of cereal.

Keep the portion modest so your stomach stays comfortable. If mornings are rushed, even a few easy carbs beat running on empty for many people. You can experiment to find what sits best for you.

Should you ever run on an empty stomach?

Short, easy runs on an empty stomach are fine for many runners, especially first thing in the morning. If the run is light and under about an hour, you may not need to eat first. Listen to how you feel.

For longer or harder efforts, eating something first usually helps you perform and finish stronger. Running low on fuel can make quality workouts feel harder than they should. There is no single right answer here, and it may depend on the run, the time of day, and your body.

What to eat during a run

A lot of runs do not need any fuel at all. Once your efforts get longer, though, taking in carbs during the run helps you hold your pace and finish well. The goal is simple, steady energy that your stomach can handle on the move.

When mid-run fueling matters (runs over 60 to 90 minutes)

For runs under about an hour, water and your stored glycogen are usually enough. Fueling becomes more useful as runs stretch past roughly 60 to 90 minutes, when glycogen starts to run low. That is when a little carbohydrate during the run can keep your energy steady.

The exact threshold varies by runner, pace, and how well fueled you were beforehand. Some people feel a lift from fueling earlier, while others can go longer comfortably. This is worth practicing in training, not testing for the first time on race day.

How many carbs per hour — and easy ways to get them

A common starting range is 30 to 60 grams of carbohydrate per hour on longer runs, according to Mayo Clinic Health System. You can get there with sports gels, chews, a sports drink, banana, or dried fruit. Whole foods and sports products both work, so pick what sits well for you.

Sip water alongside gels or chews to help them digest. Start fueling before you feel empty rather than waiting until you fade. Some experienced endurance runners train their gut to handle more per hour, but higher intakes should be built up gradually and personalized.

What to eat after a run for recovery

Recovery starts the moment you stop running. What you eat afterward helps your muscles refill glycogen and repair, which is what lets you train again sooner and feel better doing it. Post-run recovery nutrition is one of the highest-payoff habits a runner can build.

The recovery window: carbs plus protein within 30 to 60 minutes

Pairing carbohydrate with protein after a hard or long run supports both refueling and repair. Research in Sports Medicine describes how combining carbohydrate and protein after exercise supports muscle recovery, and can help restore glycogen when carbohydrate intake alone is limited. Mayo Clinic Health System similarly suggests including protein within about 30 minutes of finishing.

Aim to eat within roughly 30 to 60 minutes when you can. The window is a helpful target rather than a hard deadline, and getting a solid meal in a little later still counts. If your appetite is low right after running, a drink or small snack can bridge the gap until a full meal.

Real recovery meals and snacks

Recovery food does not need to be complicated. Chocolate milk, Greek yogurt with fruit and granola, a turkey and cheese sandwich, or eggs with toast and fruit all pair carbs with protein. A smoothie with milk, fruit, and yogurt is an easy option when you are not hungry yet.

Then follow up with a balanced meal within a couple of hours. Consistency across the day matters more than any single perfect snack. Choose recovery foods you actually enjoy and will reach for after most runs.

“When a runner keeps hitting a wall and recovering slowly, the first thing I check is whether they are eating anything at all in the hour after a hard session. We usually start small, like adding a glass of chocolate milk or a yogurt with fruit right after the run. That one simple habit is often enough to make the next day’s training feel noticeably easier.” — Bridget Isaacs, MS, RD

Hydration and electrolytes for runners

Fluid balance affects how you feel and how you perform, especially in heat or on long runs. Hydration for runners is less about hitting a rigid number and more about drinking consistently and reading your body. Your needs vary with sweat rate, weather, and effort.

How much to drink before, during, and after

Start runs already hydrated by drinking normally through the day and having some fluid in the hours beforehand. During longer runs, sip to thirst rather than forcing large amounts at once. After running, drink steadily to replace what you lost, using thirst and how you feel as your guide.

One simple, personal check is your urine color, which is generally pale yellow when you are well hydrated. Sweat rates differ widely between runners and days, so there is no universal ounces-per-mile rule. You can learn your own pattern with a little attention over a few weeks.

When you need electrolytes, not just water

For shorter runs, plain water usually does the job. Electrolytes, especially sodium, become more useful on longer runs, in hot or humid weather, or if you are a heavy or salty sweater. Signs like white salt marks on your skin or clothes can be a clue.

In those situations, a sports drink, electrolyte tablet, or salty food alongside water can help you absorb and hold onto fluid. Drinking very large amounts of plain water without any sodium on long efforts is worth avoiding. If you sweat heavily or run long often, personalizing your electrolyte plan with a dietitian can help.

Fueling for longer efforts: long runs, races, and carb-loading

Longer efforts raise the stakes on fueling. The half marathon, marathon, and long training runs draw down glycogen far more than an easy weekday run. That makes your before, during, and after strategy matter more. Fueling for long-distance and marathon runners is mostly about topping off stores and practicing your plan.

Does carb-loading actually work?

Carb-loading is a widely used strategy for longer endurance events, generally those lasting around 90 minutes or more. The idea is to raise the carbohydrate in your meals in the day or days before a race. Your muscles then start with fuller glycogen stores. It is not about one giant pasta dinner.

It is also not needed for shorter runs or most everyday training. For a 5K or an easy long run, normal balanced eating is plenty. Whether and how much to carb-load depends on the distance, your body, and how you respond, so it is worth practicing before a goal race.

The night before and race morning

The night before a long run or race, lean toward a familiar, carb-rich meal that you know sits well. Keep it moderate in fat and fiber to protect your stomach, and skip untested new foods. Hydrate normally and avoid the urge to dramatically overeat.

On race morning, eat a carb-focused breakfast a few hours before the start if your schedule and stomach allow. Toast with banana and honey, oatmeal, or a bagel are common choices. Then top off with a small snack closer to the start if you need it, using exactly what you practiced in training.

Do runners need supplements?

Most runners can meet their needs through food, and whole foods should be the foundation. Supplements are tools for specific gaps, not a shortcut around eating well. Before adding anything, it helps to look at what your actual diet and training call for.

That said, some supplements have a place for some runners. Iron may be appropriate if bloodwork confirms a deficiency, which is not uncommon among runners and worth testing rather than guessing. Vitamin D, calcium, and, for some athletes, performance aids like caffeine or creatine can play a role depending on individual needs.

Because supplements can interact with medications and are not one-size-fits-all, they are best chosen with professional guidance. A registered dietitian can review your diet, labs, and goals and tell you what is genuinely worth taking. This keeps you from spending money and effort on products your body does not need.