Nutrition and Supplements for Runners

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Sunday, after the long run: pancakes, eggs, a smoothie, and still hungry by two o’clock. Runners burn a lot, and how they eat shapes how they train, how they recover and how often they get hurt. Yet running also has a long, unhealthy streak of “lighter is faster” thinking, especially in high school and college distance running. This page covers how much runners need to eat, carbs and protein by training load, the nutrients runners most often run short on (iron, calcium, vitamin D), and which supplements have real evidence, with third-party testing as the filter.

General information for healthy runners, not personal nutrition advice. Talk to a doctor or registered sports dietitian before starting supplements, especially if you’re under 18, pregnant, take medication or have a health condition. Back to the running hub.

First: eat enough

The International Olympic Committee’s 2023 consensus statement on Relative Energy Deficiency in Sport (REDs) describes what happens when athletes don’t eat enough for their training: hormones, bones, the heart, mood, immunity and performance all suffer, in men and women. In distance running it shows up as stress fractures, missed periods, constant fatigue and stalled progress. One study of 156 male collegiate distance runners found 27% had a bone stress injury over about two years, more often when energy intake, body weight and bone density were low. Eating enough isn’t a nice extra; it’s part of the training. Warning signs and when to get help are on our running injuries page.

Carbohydrates by training load

Carbs are the main fuel for running at any real effort. The joint position statement from the American College of Sports Medicine (ACSM), the Academy of Nutrition and Dietetics and Dietitians of Canada scales them to training:

Training day	Carbs per kg body weight per day	60 kg (132 lb) runner	75 kg (165 lb) runner
Light (low intensity or skill work)	3–5 g	180–300 g	225–375 g
Moderate (about 1 hour a day)	5–7 g	300–420 g	375–525 g
High (1–3 hours a day, moderate to hard)	6–10 g	360–600 g	450–750 g
Very high (4–5 hours a day)	8–12 g	480–720 g	600–900 g

A simple way to apply it: bigger portions of rice, pasta, potatoes, oats, bread and fruit on long-run and workout days, smaller on rest days. Race-week carb loading is on our race day page.

Protein

ACSM’s range for athletes is 1.2–2.0 g of protein per kg of body weight per day (about 72–120 g for a 60 kg runner), spread across meals, with about 0.25–0.3 g/kg (15–25 g) after hard sessions. Most runners can get there from food: eggs, dairy, meat, fish, beans, tofu. A protein powder is a convenience, not a requirement. Older runners may need more per meal; see recovery for runners over 50.

Iron, calcium and vitamin D

• Iron: ACSM notes female athletes have higher iron requirements, and low intake, low energy intake and blood loss all affect iron status. Iron deficiency is common in female endurance athletes; in one small study of highly trained, non-professional women, 6 of 13 were iron deficient. But don’t self-prescribe: a UEFA expert statement warns that routine iron supplementation “can do more harm than good”. Ask your doctor for a blood test (including ferritin) if you’re tired, short of breath on easy runs or your times are slipping.
• Calcium and vitamin D: the American Academy of Orthopaedic Surgeons (AAOS) lists low vitamin D and poor nutrition among risk factors for stress fractures. Dairy or fortified alternatives, leafy greens and some sun or food sources of vitamin D are the base; your doctor can test vitamin D if you’ve had a bone stress injury.
• Fluids and sodium day to day: sweat rates range from 0.3 to 2.4 L an hour (ACSM). Drink with meals and around runs, and use electrolytes for long or hot runs.

Supplements: what has evidence

The IOC’s 2018 consensus statement on dietary supplements separates sports foods (sports drinks, gels, bars, protein shakes: convenient ways to get nutrients) from performance supplements. Among the latter, only a few have enough support to suggest “marginal performance gains may be possible”: caffeine, creatine, nitrate (beetroot juice), sodium bicarbonate and possibly beta-alanine. The statement stresses that responses vary and that a good diet comes first. A UEFA expert group adds that the evidence for caffeine and creatine is stronger than for beta-alanine or nitrate.

• Caffeine is the one runners use most, often in gels (Maurten CAF 100: 100 mg per gel). Side effects include anxiety, stomach upset, a racing heart and poor sleep. It isn’t for everyone (caffeine sensitivity, heart conditions, pregnancy); check with your doctor and follow the label.
• Creatine is well studied for strength and sprint training and can add 1–2 kg of body weight (UEFA). That’s useful for the gym and for sprinters, less obviously so for distance runners.
• Multivitamins and electrolytes fill gaps; they don’t replace food.

Why third-party testing matters: in an analysis cited by UEFA, about 15% of 634 supplements from 13 countries contained prohormones (banned steroids) not listed on the label. Under anti-doping rules, athletes are responsible for whatever is in their body. Programs such as NSF Certified for Sport and Informed Sport / Informed Choice test for banned substances; they lower the risk but can’t eliminate it, and they don’t test whether a supplement works. High school and college runners may be drug tested too.

Teens: the American Academy of Pediatrics says energy drinks and stimulants have no place in children’s and adolescents’ diets, and recommends against creatine for young athletes. Food first, with a sports dietitian if needed.

Products many runners use

Product	Per serving (label)	Third-party testing	About per serving
Thorne Whey Protein Isolate	21 g protein	NSF Certified for Sport	$2.17
Klean Athlete Klean Multivitamin	2 tablets, 1,000 IU vitamin D3, no iron listed	NSF Certified for Sport	$1.53
Maurten Gel 100 CAF 100	25 g carbs, 100 mg caffeine	Informed Sport (maker says)	$4.33
Skratch Labs Hydration Mix	19–20 g carbs, 400 mg sodium	Maker says NSF; not found in NSF database	$1.20
Nuun Sport	300 mg sodium, 1 g sugar	Informed Choice (maker says)	$0.75

Prices are what we saw at the maker or a major retailer in October 2026; check before you buy. Certification statuses change, so check the NSF and Informed Sport databases for the exact product and lot. Follow the label; check with a doctor or dietitian if you have high blood pressure, kidney or heart problems, or are on a low-sodium diet.

Full comparisons in our guides to protein powder, multivitamins, electrolytes, energy gels and creatine, or the Nutrition & Supplements category. For recovery meals, see running recovery; team-sport players can compare with soccer nutrition.

Running nutrition: FAQs

How many carbs do runners need a day?

It depends on training. ACSM’s ranges go from 3–5 g per kg of body weight on light days to 6–10 g/kg for 1–3 hours of training a day. A 60 kg runner doing about an hour a day needs roughly 300–420 g.

Do runners need protein powder?

Not necessarily. ACSM’s 1.2–2.0 g/kg a day is reachable with food for most runners. A shake is handy after long runs or when you can’t eat soon; if you use one, pick a third-party tested product.

Should female runners take iron?

Only if a doctor finds low iron. Female athletes have higher needs and deficiency is common, but routine supplementation without testing can do more harm than good, per a UEFA expert group. Ask for a blood test that includes ferritin.

Does caffeine help running performance?

Caffeine is one of the supplements with the strongest evidence, per the IOC and UEFA statements, but responses vary and side effects are real. It isn’t for everyone; try it in training, follow the label and check with your doctor if you have a heart condition or are pregnant.

What does NSF Certified for Sport mean?

The product has been tested for substances banned in sport and checked against its label. It lowers the risk of an accidental positive test, but no program can guarantee zero risk, and certification doesn’t mean the supplement improves performance.