Diet for the ultra runner

Last updated: 22-Aug-18

By Diana Green

The key to success for an ultra runner is the ability to maintain a constant and high rate of energy output over a prolonged period. In order to do this, both training and nutrition play a vital role. Diana Green, is an experienced nutritionist and chef who is also a keen runner and mountain biker. Here she looks at an in-depth strategy for eating as you train and run long distances.

This is a detailed plan of how to analyse your eating, plan your intake and then follow that plan. It includes examples for an average man and woman to give you guidance. It also provides a number of fantastic recipes to set you on the right path. There is information on pre and post run eating, a look at fat adaptation and advice on how to stop things going wrong.

Remember, it will take work to get your nutrition strategy right, but if you do, it will make an immense difference to your running.


Here are some of the basic rules that you need to apply every day in order to maintain optimal health and fitness. They are common sense but they are also very easy to ignore as you reach for the fast option.

Eat Effectively

Plan your meals in advance on both training and rest days. Timing of meals is important to balance energy levels and maximise fuel economy during longer runs.

Eat for Injury Prevention, Healing and Health

As well as fueling your running, foods rich in healthy fats and micronutrients are essential to aid recovery, prevent injuries, maintain a healthy immune system and promote restful sleep.

Eat for your Ideal Body Weight 

Body weight can affect your performance. A leaner body is more efficient at delivering oxygen, dissipating heat and burning carbohydrates.

Eat for Enjoyment

For any diet to be sustainable it must be enjoyable. Don’t give up your favourite foods, if you know they are not the best choices make healthier adaptations or keep them as ‘special treats’.

Eat Simply and Varied

Create simple meals based around your dietary targets. Don’t over focus on a few ‘superfoods’. As much variety as possible will give you the range of nutrients that your body needs.


Once you have got the basic rules down, it is time to plan your diet. There is no “one size fits all” and actually there is quite a bit of work involved as you find out what is going to work for you. It may sound a bit glib, but you really DO have to take responsibility for your own nutrition, just as you do for your training. The good news is that once you have done it, you can plan a diet that works for you as an individual and that is a very powerful thing.

Here are the basic steps:

Calculate your individual energy requirements.

Estimate your current intake of calories by recording a week’s diet (you can use apps such as ‘myfitnesspal’ for this).

Decide on a weight target to reduce your weight, aim for a reduction of approx 500 calories a day below your energy requirements. It is not recommended to reduce lower than this or within 10 weeks of your target race, as you risk compromising performance.

Likewise if you want to increase your weight, add an extra 500 calories per day. Once you have defined your basic calorie intake, you need to go further and analyse down.

The next step is to work out your carbohydrate, protein and fat intake based on your energy requirements and weight targets.

Calculate carbohydrate, fat and protein.


Carbohydrate is the main energy source for the body and brain.

Choose slow releasing and nutrient dense carbohydrates – fruit, vegetables, pulses and whole grains.

Calculating Carbohydrate Intake

There are two different ways to calculate carbohydrate requirements for runners based either on total calorie intake or body weight together with activity levels.

  1. Approx 60 % of total calorie intake from carbohydrates.
  2. Based on body weight and activity levels: take a base line of 3 g per kg of body weight and add between 1 and 2 g of carbohydrate for every 20 miles running per week.


Protein has a very important role to play supporting your general health and training.

Protein is needed for growth and repair of tissue, regulating metabolism, manufacturing enzymes and hormones, transporting nutrients in and out of cells and proper immune response.

Choose protein foods with a high biological value (containing a complete balance of amino acids which can be readily used by the body) lean meats, fish, eggs, low fat dairy and soya. The protein in nuts & seeds, pulses and grains will have a lower bio-availability.

If you are a vegetarian, in order to meet your protein requirements, you need to eat a mixture of protein foods over the day so that the shortfall of amino acids in one food is complemented by higher amounts in another such as pulses and grains.

Calculating Protein Intake

There are two different ways to calculate protein requirements for runners based either on total calorie intake or body weight together with activity levels:

  1. Approx 15% of total calorie intake from protein.
  2. Based on body weight and activity levels: 20 to 40 miles running per week requires approx 1.5 g protein per kg of body weight.


Once you have calculated your protein and carbohydrate requirements the remainder of calories come from fat aiming for approx 25% of total calories. However this doesn’t make fats less important as they are needed for brain & nerve function, balancing hormones and most importantly for controlling inflammation.

Focus on foods higher in essential fats (oily fish, nuts & seeds, free range meats) and monounsaturated fats (olive oil) avoiding trans fats often found in high fat snacks (crisps, biscuits) which can interfere with cell functioning.


Combine protein and a carbohydrate with fruit/vegetables to achieve your target nutrient balance.

DOWNLOAD this great choice of recipes. Just click on each one to get the pdf:

  Proteins. Lunch & Supper.   Proteins  
  Carbohydrates. Lunch & Supper.   Carbohydrates  
  Vegetables. Lunch & Supper.   Salads, vegetables and fruit  
  Breakfast   Cereal bars and biscuits   Breakfast
  Snacks   Snacks to buy  



  • Meal plan 1
  • Meal plan 2

Download all recipes and meal plans here.


Are the recommended macro nutrient targets right for me?

Individual requirements will vary. Take the recommended targets as a starting point and determine what is right for you based on how you are feeling. You may chose to fluctuate your intake based on the intensity of your training days. Listen to your body and appetite.

Do I need to achieve my target proteins, carbohydrates and fats everyday?

The ratios of proteins, fats and carbohydrates in natural foods will vary, so aim to meet a daily average over a week.

Am I getting enough calories to support my training?

It is important to supply enough fuel to support your energy requirements and recovery. A simple way to identify whether you are consuming enough calories is to record your weight on a weekly basis. Any significant weight loss represents an energy deficit.

Do I need protein shakes?

It is only necessary to have protein shakes if you cannot get enough protein from your diet or it is a convenient quick source of protein i.e as part of recovery nutrition. Little benefit is to be gained from an intake much above your  protein requirements.


Fat adaptation – ‘train low, race high’

The average runner can store about 2,500 calories of carbohydrate, enough to last maybe a couple of hours, however they also carry a reservoir of up to 50,000 calories from fat. Encouraging the body to tap into its fat stores as an energy source as well as carbohydrate can improve endurance.

To promote fat burning adaptation every week do one of your easy runs in a low-carb state, ideally in the morning before breakfast.


Consume carbohydrate within 30 minutes of finishing a training sessions when your muscle glycogen stores are most receptive.

A combination of carbohydrate and protein promotes insulin release which maximises gylcogen replenishment and the transport of amino acids into muscle cells promoting protein synthesis and muscle repair.

Aim for 300-400 calories of 4:1 grams of carb to protein. This is one time when including some fast releasing snacks can be good to get your glycogen recovery off to a quick start.

Carb loading
Pre race carb loading while reducing training for 3 days before an event will increase muscle carbohydrate stores. Aim for approx 10 g of carbohydrate per kg of body weight.


Not eating enough protein

If you fail to consume enough protein when training your body will break down muscle to fuel your runs.

Eating too many carbohydrates

Beware of eating too many carbohydrates particularly fast releasing snacks (crisps, biscuits) which can result in not only more calories than you need but also taking the place of other important nutrients (i.e protein, healthy fats).

Lack of planning

Do a supermarket delivery order every week and keep a good selection of proteins, carbohydrates and vegetables in your fridge and cupboards (both ‘easy cook’ and ‘no cook’) enabling you to make super quick meal decisions.

Forgetting the micronutrients

Diet is not only about the macro nutrients (protein, carb, fat), eat plenty of fruit and vegetables and a large variety of foods to ensure optimum performance and health.

Missing meals

If you know you are going to miss a meal due to a busy schedule turn your easy snacks into bigger portions that you can eat on the go.

Difficulty calculating calories & macronutrients

Get to know packaging displays of nutrition information. You will find that many recipes both on line and in books/magazines will include the nutrition information. Becoming familiar with the appearance of your chosen portion sizes by using a certain plate size or measuring spoon  will make repeated weighing unnecessary.

Too rigid a plan

Everyone’s energy and nutrient requirements are individual depending on lifestyles, age and health. Having a nutrition plan enables you to make changes to that plan to achieve your personal targets and optimum health.

Unachievable plan

If your plan is unachievable due to lack of cooking/preparation time, unavailable food choices it will potentially become a stress which can be overall detrimental to your training and health. Focus on the meals that you have the easiest control over (i.e breakfasts, snacks) and the timing of your meals.

Poor Digestion

It is important to have a diet that is well tolerated by your digestive system. Creating a nutrition plan might mean some major changes to the types of foods that you currently eat. Make gradual changes and avoid foods that cause any digestive discomfort.

Untested Plan

Test your carb loading strategy before a long training run and find what works for you.

Creating a really good diet for running is going to take time and patience. It will reward you with results, though. Good luck with it!

Don’t forget to download the recipes and meal plans.

For more from Diana, check out her website.
She also holds running camps in the New Forest (England, UK).



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Entry Fee
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Date Range

Global - Virtual


A virtual race which can be run at any time shown on the dates shown, on any type of terrain in any country.

Suitable for

For runners from beginners to experienced as you choose your own course and challenge based on the guidelines and options set by the virtual race organiser.

Endurance - Multi-activity


An ultra distance race including at least two of the following activities such as running, swimming, cycling, kayaking, skiing and climbing. It may also include different climatic conditions (eg ice, snow, humidity, cold water, mud or heat).

Suitable for

Experienced multi-skilled athletes who have trained for the different activities included in this event. Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements and any specialist equipment required such as a wetsuit, skis or a mountain bike.



Increase of up to 2000 metres with very challenging climatic conditions (e.g. ice, snow, humidity, heat or at high altitude)

Suitable for

Very experienced long distance ultra runners (min 3 years’ experience) or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races is often subject to receipt of a recent medical examination certificate. Purchase of specialist kit is often recommended for these races.



Increase of up to 2000 metres with some challenging climatic conditions (e.g. ice, snow, humidity or heat)

Suitable for

Experienced runners who have completed at least 4 ultras in last 12 months, or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements.



Increase of up to 1500 metres

Suitable for

Runners who have completed several ultra distances or similar events, or are doing long distance running regularly, with elevation shown.



Increase of up to 1000 metres

Suitable for

Runners who have completed at least one ultra in last 6 months or are doing long distance running (>26 miles) regularly, with elevation shown.



Very little change < 500 metres

Suitable for

First ultra event. Runners completing a marathon or doing regular long distance running (>26 miles) in the last 6 months.