How Many Calories Should A Runner Eat? Energy Availability Truth

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Amber Sayer, MS, CPT, CNC
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Amber Sayer is our Senior Running Editor, and a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics, as well as a Certified Personal Trainer and running coach for 12 years.

Senior Running Editor

Running burns a lot of calories, and it takes a strategic nutrition plan to fuel your workouts and recover efficiently once you have finished your run.

But how many calories should a runner eat?

No matter whether you’re a runner trying to lose weight, maintain your weight, or gain weight, it can be helpful to know how many calories runners should eat.

In this article, we will look at the caloric needs of runners so that we can answer the important question, “How many calories should a runner eat?”

We will cover: 

  • Do Calories Matter for Runners?
  • How Many Calories Should a Runner Eat?
  • Calculating Caloric Needs for Runners

Let’s jump in!

A person running.

The Honest Truth About How Many Calories A Runner Should Eat

The popular framing — “total calories in vs out” — misses the variable that actually predicts how a runner’s body responds: energy availability, defined as the calories left over after exercise expenditure to support all other physiological functions. That number, expressed per kg of fat-free mass per day, is what determines whether training produces adaptation, plateau, or pathology — and it’s a different concept from gross daily calorie counts.

Energy availability: the variable that beats “total calories”

Energy availability (EA) = (energy intake − exercise energy expenditure) / fat-free mass, expressed in kcal/kg FFM/day. The IOC consensus on Relative Energy Deficiency in Sport (RED-S) places the healthy threshold at approximately 45 kcal/kg FFM/day, with a clinical danger zone below approximately 30 kcal/kg FFM/day where menstrual function, bone density, immune function, and protein synthesis all degrade 1Mountjoy M, Sundgot-Borgen J, Burke L, et al. The IOC consensus statement: beyond the Female Athlete Triad — Relative Energy Deficiency in Sport (RED-S). Br J Sports Med. 2014;48(7):491-7.. The 2018 update extended this framework to broader cardiovascular, GI, and psychological consequences 2Mountjoy M, Sundgot-Borgen JK, Burke LM, et al. IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. Br J Sports Med. 2018;52(11):687-97.. The practical implication: a 60 kg runner with 50 kg FFM running 90 minutes (~700 kcal expenditure) needs intake above approximately 2,950 kcal to stay above the EA threshold, regardless of whether weight loss or maintenance is the goal — the issue is not body weight but tissue function. Loucks’ controlled-feeding studies established the threshold experimentally 3Loucks AB, Thuma JR. Luteinizing hormone pulsatility is disrupted at a threshold of energy availability in regularly menstruating women. J Clin Endocrinol Metab. 2003;88(1):297-311..

Training-load adjustment and the moving target

Energy expenditure scales roughly linearly with running distance: about 1 kcal per kg bodyweight per km of running, with modest economy and pace adjustments. A 70 kg runner doing 60 km/wk thus spends approximately 4,200 kcal/wk on running alone — an additional 600 kcal/day on top of basal needs 4Margaria R, Cerretelli P, Aghemo P, Sassi G. Energy cost of running. J Appl Physiol. 1963;18:367-70.. The mistake most generic calorie targets make is using a static daily number rather than scaling with weekly load: peak-training weeks may need 800–1,200 kcal/day more than recovery or taper weeks. The concept of “periodised nutrition” in elite endurance athletes — matching macronutrient timing and total intake to training stimulus — is well-described in the Burke and colleagues sports-nutrition literature 5Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci. 2011;29(Suppl 1):S17-27.. The flipside: protein needs in endurance runners are higher than the general-population RDA — approximately 1.2–1.6 g/kg/day in trained runners, supporting both training adaptation and recovery from microtrauma 6Phillips SM, Van Loon LJ. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci. 2011;29(Suppl 1):S29-38..

Macros: carbohydrate as the variable lever

Carbohydrate is the macronutrient that has to flex with training load. The contemporary recommendations for runners scale with daily volume: about 3–5 g/kg/day for low-intensity (under 60 min) days, 5–7 g/kg/day for moderate volume (1–3 h), and 8–12 g/kg/day for high-volume marathon-block training and race-week loading 7Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci. 2011;29(Suppl 1):S17-27.. Glycogen storage capacity is finite — about 500–700 g across muscle and liver in a trained runner — and depletion is the well-known “wall” of endurance racing 8Costill DL. Muscle glycogen utilization during prolonged exhausting exercise. J Appl Physiol. 1971;31(6):834-8.. Fat needs sit at roughly 20–35 percent of total energy intake for most runners, with omega-3 sufficiency the only fat target with strong evidence for performance and recovery 9Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement: Nutrition and Athletic Performance. Med Sci Sports Exerc. 2016;48(3):543-68.. The under-recognised piece: in-race carbohydrate intake is itself an adaptation. The gut’s capacity to absorb 60–90 g/h of carbohydrate must be trained, with 4–6 weeks of practice in long runs needed to develop tolerance 10Jeukendrup AE. Training the gut for athletes. Sports Med. 2017;47(Suppl 1):101-10..

Under-fueling: the under-recognised RED-S risk

The pattern of unintentional under-fueling in trained runners is well-documented and matters more than the cosmetic question of weight. Tornberg et al. found low energy availability in roughly 40 percent of female endurance athletes assessed and a comparable rate among male endurance athletes, often without intentional restriction — just a mismatch between training appetite signals and exercise expenditure 11Tornberg ASB, Melin A, Manderson Koivula F, et al. Reduced neuromuscular performance in amenorrheic elite endurance athletes. Med Sci Sports Exerc. 2017;49(12):2478-85.. The cascade in chronic low EA includes suppressed luteinising hormone pulsatility, reduced bone-mineral density, increased stress-fracture risk, and impaired training adaptation — consistent in male and female athletes despite different presenting symptoms 12Mountjoy M, Sundgot-Borgen JK, Burke LM, et al. IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. Br J Sports Med. 2018;52(11):687-97.. The clinical signal worth knowing: training-related fatigue that doesn’t respond to recovery weeks, plateaued performance with stable or rising training stress, and elevated injury rate are often misread as “overtraining” when the underlying issue is undereating 13Stellingwerff T, Heikura IA, Meeusen R, et al. Overtraining syndrome (OTS) and relative energy deficiency in sport (RED-S): shared pathways, symptoms and complexities. Sports Med. 2021;51(11):2251-80..

When “eat less to lose weight” backfires

The harder version of this question — “how do I lose weight while running” — deserves separate treatment because the standard answer is often counterproductive. Aggressive calorie deficits in runners (more than approximately 500 kcal/day below energy needs) reliably reduce training quality and adaptation, often producing weight loss faster than fitness can be rebuilt — the result is a faster but lighter runner who is also under-recovered and at higher injury risk. Slower, periodised approaches — small deficits in lower-volume blocks, neutral or slight surplus in peak-training and race-week — preserve adaptation and produce more durable body-composition change 14Stellingwerff T. Case study: body composition periodization in an Olympic-level female middle-distance runner over a 9-year career. Int J Sport Nutr Exerc Metab. 2018;28(4):428-33.. The honest reading: gross calorie targets are a starting point; energy availability is the variable to manage; macronutrient timing matters; and aggressive cutting strategies adopted from non-athletic populations don’t translate cleanly to trained runners.

Do Calories Matter for Runners?

Calories can be a polarizing concept when it comes to weight loss. 

Some people believe that weight loss is all about the simple equation or inequality between calories in (the calories you’re consuming) versus calories out (the calories you’re burning).

When these two are equal, your weight will be stable. 

When you’re eating a higher number of calories than you’re burning, you’ll gain weight, and when you’re burning more calories than you’re consuming, you’ll lose weight.

Other people believe calories are only a small piece of the overall picture of weight loss, so worrying about “calorie math” is useless.

However, even if you set aside the potentially controversial relationship between calories and weight loss, it can still be quite valuable to know how many calories a runner should eat.

Calories are the energy the body needs when you run or do any form of physical activity.

If you’re not ingesting an adequate number of calories, your performance will suffer, and your recovery will be compromised. 

Injury risk can increase, and you might feel sluggish and tired during your workouts.

If you’re eating too many calories, you will gain weight in the form of body fat, which can also hamper performance, depending on your current weight and body composition.

Therefore, knowing how many calories you need to support your running can absolutely be an important part of successful training.

A person making a shake.

Related: Calories Burned Per Activity Calculator (800+ Activities)

How Many Calories Should a Runner Eat?

Let’s get down to the practical side of things: how many calories should a runner eat?

This is an impossible question to answer in a specific way for every runner because the number of calories you need depends on many factors.

The main factors to consider when determining how many calories a runner should eat include:

#1: Your BMR

Your basal metabolic rate, or BMR, refers to the number of calories your body burns every day just to sustain your life.

Processes like breathing and circulating blood to your tissues require a certain amount of energy.

Your BMR is mainly influenced by your body weight and composition, your age, and your sex.

Related: TDEE And BMR Calculator

A runner.

The larger you are and the more muscle mass you have, the higher your BMR will be.

​​To make two simple comparisons, a runner who weighs 95 pounds will have a lower BMR than a runner who weighs 175 pounds, and a runner who weighs 180 pounds with 12% body fat will have a higher BMR than someone who also weighs 180 pounds but has 28% body fat.

In terms of sex, males typically have a higher BMR than females, primarily because of differences in lean body mass and the relative size of metabolically-active organs like the liver.

Finally, BMR usually decreases with age, largely due to sarcopenia (muscle loss).

The American Council on Exercise suggests that your BMR usually represents about 60-75% of the total number of calories you burn in a day. This percentage will vary based on how active you are, both in terms of your running training as well as general physical activity as you go about your day.

In terms of determining your BMR for the purposes of calculating the number of calories runners need to eat, you have to use a BMR or RMR (resting metabolic rate) formula to estimate this value unless you go to a physiology lab for metabolic testing.

Studies show the Mifflin-St Jeor Equation is the most accurate, yielding an estimation that is typically accurate within 10% of measured resting metabolic rate.

Though the formula calculates RMR, this value is close enough to BMR to be used as a substitute.

The Mifflin-St Jeor formulas for each sex are as follows:

Men: (10 x weight (kg)) + (6.25 x height (cm)) – (5 x age (y)) + 5 

Women: (10 x weight (kg)) + 6.25 x height (cm) – (5 x age (y)) – 161

You can use our TDEE Daily Calorie Calculator to calculate your BMR and better understand your own daily energy requirements.

A person calculating calories figuring out how many calories should a runner eat?

#2: Your Weight Goals

One of the most critical factors determining how many calories a runner should eat per day is the desired weight outcome.

Do you want to lose weight, maintain your weight, or gain weight?

Runners who have a goal of weight loss will need to generate a caloric deficit, meaning that they will be eating fewer calories per day than they are burning.

Runners who have the goal of weight maintenance will want to have a balance between the number of calories they are consuming and the number they are burning in a day.

Finally, runners who want to gain weight should eat a higher number of calories than they are burning every day in order to create a caloric surplus.

A runner.

#3: The Amount of Training You Are Doing

Your training, in terms of how much you are running, what types of workouts you are doing, and any other planned exercise you are doing, greatly affects how many calories you need to eat as a runner.

Wearing a heart rate monitor while you run is one of the most accurate ways to estimate the number of calories you burn during your workouts.

You can also estimate the number of calories you burn running by using the METs values for different running speeds.

The Compendium of Physical Activities reports that running can be the equivalent of approximately 6-20 METS or so, depending on pace or effort level. For example, running 5 miles per hour, or 8 kilometers per hour, has a METs value of 8.3.

You can see the various METS for running at different paces in the table below:

METSPace (mph)Pace (kph)
6.04 mph (15 min/mile) 6.4 kph
8.35 mph (12 min/mile) 8 kph
9.05.2 mph (11.5 min/mile) 8.37 kph
9.86 mph (10 min/mile) 9.66 kph
10.56.7 mph (9 min/mile) 10.78 kph
11.07 mph (8.5 min/mile)  11.27 kph
11.57.5 mph (8 min/mile) 12.1 kph
11.88 mph (7.5 min/mile)12.87 kph
12.38.6 mph (7 min/mile)  13.84 kph
12.89 mph (6.5 min/mile)  14.48 kph
14.510 mph (6 min/mile)  16.1 kph
16.011 mph (5.5 min/mile) 17.7 kph
19.012 mph (5 min/mile) 13.3 kph
19.813 mph (4.6 min/mile)20.92 kph

More information about this process and how to calculate the number of calories you burn running can be found here.

How Many Calories Should A Runner Eat? Energy Availability Truth 1

#4: Your Overall Activity Level

In addition to the number of calories you burn during your runs and other types of planned workouts, you also burn calories throughout the day as you perform your activities of daily living, job, etc.

Recall that BMR only constitutes the number of calories you burn per day, resting completely still in a bed for the entire day.

It takes additional energy, and thus burns calories, to get out of bed and do all of the various activities of daily living like going to work, preparing meals, basic hygiene, walking the dog, taking care of your children, etc.

The more movement you make throughout the day, including standing, walking, and carrying things, the higher your caloric needs will be.

To estimate the contribution of lifestyle physical activity to your overall caloric needs, most BMR or RMR equations have you apply an “activity multiplier.”

When you use the Mifflin-St Jeor equation to estimate your RMR, you multiply the value by the following scale factors for physical activity levels:

  • Sedentary = RMR x 1.2
  • Lightly active = RMR x 1.375
  • Moderately active = RMR x 1.55
  • Active = RMR x 1.725
  • Very active = RMR x 1.9

For example, a runner who sits at a desk all day for work after running and does some light housework might multiply their BMR by 1.375 to account for their daily physical activity, but a runner who is a construction worker or who works on their feet all day after their run might multiply their BMR by 1.9.

A person calculating calories.

Calculating Caloric Needs for Runners

Let’s walk through an example of calculating how many calories a runner should eat per day.

Our hypothetical runner, Joy, weighs 165 pounds (75 kg) and is 66 inches tall (167.6 cm) tall. She is 38 years old.

She runs about 5 miles (8km) per day at an average pace of 9 minutes per mile (10.78 kph).

Joy is a high school English teacher who is moderately active at her job and at home with her golden retriever, Dusky.

She wants to maintain her weight, but we will also look at the scenarios in which she wants to lose weight and gain weight.

A teacher giving class.

First, we have to calculate her BMR (RMR) using the Mifflin-St Jeor formulas for women:

RMR= (10 x weight (kg)) + (6.25 x height (cm)) – (5 x age (y))– 161

RMR= (10 x 75 kg) + (6.25 x 167.6 cm) – (5 x 38 years) – 161

= 1,447 calories per day.

In terms of her running, we can use the METs value of running at a 9-minute per mile pace, which is 10.5 METs.

Using this METs values, we can calculate the number of calories Joy burns running based on her body weight and the duration of her workout using the equation to determine energy expenditure:

Calories Burned Per Minute = (METs x 3.5 x body weight in kilograms) / 200 

= 10.5 METS x 3.5 x 75 / 200 = 13.8 calories per minute.

Then, because she runs 5 miles at a 9-minute-per-mile pace, we multiply the number of calories burned per minute by 45 minutes = 13.8 x 45 = 621 calories. 

How Many Calories Should A Runner Eat? Energy Availability Truth 2

In terms of her physical activity level, we determined Joy is moderately active, which means we need to multiply her RMR by 1.55:

1,447 x 1.55 = 2242.8 calories

Adding the number of calories she burns running brings us to her total daily energy expenditure:

2242.8 + 621 = 2863.8 calories per day

The final step would be adjusting her calories based on her weight goals. 

Since Joy is looking to maintain her weight, she should each about 2865 calories per day on her running days.

If she wanted to lose weight, we would reduce this number.

You lose one pound of fat for every 3,500-calorie deficit you create, so if you want to lose one pound per week, you need to eat 500 calories less than you burn per day.

For Joy, this would be 2865-500 = 2365 calories.

If she wanted to gain one pound per week, we would add 500 calories per day: 2865 + 500 = 3365 calories.

Are you ready to calculate your own daily calorie intake based on your personal goals? Give it a try!

Looking to add a new healthy diet into the equation? Check out some of our diet guides to find the best choice for you: Popular diets for runners, CICO, intermittent fasting, and the Golo diet.

A variety of food.

References

  • 1
    Mountjoy M, Sundgot-Borgen J, Burke L, et al. The IOC consensus statement: beyond the Female Athlete Triad — Relative Energy Deficiency in Sport (RED-S). Br J Sports Med. 2014;48(7):491-7.
  • 2
    Mountjoy M, Sundgot-Borgen JK, Burke LM, et al. IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. Br J Sports Med. 2018;52(11):687-97.
  • 3
    Loucks AB, Thuma JR. Luteinizing hormone pulsatility is disrupted at a threshold of energy availability in regularly menstruating women. J Clin Endocrinol Metab. 2003;88(1):297-311.
  • 4
    Margaria R, Cerretelli P, Aghemo P, Sassi G. Energy cost of running. J Appl Physiol. 1963;18:367-70.
  • 5
    Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci. 2011;29(Suppl 1):S17-27.
  • 6
    Phillips SM, Van Loon LJ. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci. 2011;29(Suppl 1):S29-38.
  • 7
    Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci. 2011;29(Suppl 1):S17-27.
  • 8
    Costill DL. Muscle glycogen utilization during prolonged exhausting exercise. J Appl Physiol. 1971;31(6):834-8.
  • 9
    Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement: Nutrition and Athletic Performance. Med Sci Sports Exerc. 2016;48(3):543-68.
  • 10
    Jeukendrup AE. Training the gut for athletes. Sports Med. 2017;47(Suppl 1):101-10.
  • 11
    Tornberg ASB, Melin A, Manderson Koivula F, et al. Reduced neuromuscular performance in amenorrheic elite endurance athletes. Med Sci Sports Exerc. 2017;49(12):2478-85.
  • 12
    Mountjoy M, Sundgot-Borgen JK, Burke LM, et al. IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. Br J Sports Med. 2018;52(11):687-97.
  • 13
    Stellingwerff T, Heikura IA, Meeusen R, et al. Overtraining syndrome (OTS) and relative energy deficiency in sport (RED-S): shared pathways, symptoms and complexities. Sports Med. 2021;51(11):2251-80.
  • 14
    Stellingwerff T. Case study: body composition periodization in an Olympic-level female middle-distance runner over a 9-year career. Int J Sport Nutr Exerc Metab. 2018;28(4):428-33.

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sayer headshot

Amber Sayer, MS, CPT, CNC

Senior Running Editor

Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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