Marathon diet plan – training phase

I have always felt that a balanced diet covers all our needs, and  extras such as  vitamin pills, protein supplements or energy drinks are unnecessary.

However, the nature of the marathon means that extra attention is needed to ensure that you don’t run out of energy on the day.  But in this post I will be highlighting the basic principles needed to develop an effective and realistic marathon diet plan for the whole training period rather than race day itself, which will be dealt with in another post.

When considering the diet for an endurance activity, there is naturally an emphasis on carbohydrates as the prime food source, since you need a good supply of glycogen to power your muscles for a prolonged period. But you also need plenty of protein to enable muscle tissues to repair effectively after each workout, some fat as an alternative energy source and to allow the absorption of the fat soluble vitamins, fibre to maintain healthy intestines, and also foods that contain antioxidants, which help mop up the extra free radicals that can be produced when we respire more rapidly. The good news is that a relatively normal well-balanced diet, perhaps chosen with a little extra thought, will cover all these bases. So let’s have a brief look at all the key components of a well-balanced diet that, along with a sensible training and recovery schedule, should give you a good chance of achieving your race goals.


Carbohydrates can be classified as simple or complex.  Simple carbohydrates are basically sugars such as sucrose (ordinary sugar), glucose or fructose.  As these require little or no digestion, they give a quick release of energy when required, and therefore can be very useful during the marathon as part of an energy drink or gel, or in sweets such as jelly babies. Most of the time, however, it is much healthier to consume complex carbohydrates, as they need to be broken down by digestion and so allow a slow and steady release of energy without rotting your teeth of giving rise to a sugar rush.

Potatoes, pasta, rice, bread and cereals are perhaps the most common go to guys for complex carbohydrate, and they all do the job effectively.  However, most dieticians would recommend focussing on less processed carbohydrate sources, such as potatoes, brown rice, quinoa and beans rather than white pasta and bread, which are the result of wheat processing.  Quinoa and beans are also good sources of protein. Wholegrain bread, rice and pasta are healthier than those made from white flour, as they contain fibre and a whole lot (like the pun?) of other important nutrients.  Oats are another good source of carbohydrate and also contain a significant amount of protein, plus a variety of vitamins, minerals and antioxidants.  And don’t forget bananas, which have the advantage of needing no preparation, as well as being a great source of  fibre and potassium.


Protein is needed to build and repair muscle tissue, so perhaps the easiest way to get this protein is to eat the muscles of another animal, ie. meat or fish.  I personally try to avoid red meat as I believe that beef production in particular is very bad for the environment and the health drawbacks (eg. the production of bad cholesterol) outweigh any advantages.  Fish (especially oily fish such as salmon, trout or mackerel), chicken and eggs are excellent non-vegan options, whilst lentils and the previously mentioned beans and quinoa are among the choices that are acceptable to everyone. Most of these foods will go at least some of the way to replacing not just the protein, but the essential vitamins and minerals (eg. iron and the B vitamins) that come with red meat.


We need some fat, as an energy source but also to supply us with fat soluble vitamins such as A and E, but the majority of people have too much fat in their diet, hence the obesity crisis.  And it’s not just that people eat too much fat, but that they are eating the wrong type of fat – the ‘bad fat’.

The ‘bad fats’ are saturated fats, found in animal fat and therefore lard and butter (and other dairy products such as cheese) and more surprisingly in coconut oil and palm oil (so palm oil production isn’t just a disaster for the rainforests, but it’s not great for human health too).  The ‘good fats’ are unsaturated fats, and these are found in almost all plant based oils (eg olive oil, sunflower oil, sesame oil and various nut oils) as well as avocados and most nuts. Peanut butter is obviously a good source, but often it contains added palm oil, so watch out for this and be prepared to pay a little more to get the palm oil free option. Oily fish, such as salmon, trout and mackerel, are also excellent sources of unsaturated fats, and also boast long chain omega 3 molecules, which have a range of key roles, including the maintenance of low blood pressure.


Pre-race nerves are very effective at promoting bowel clearance, but a longer term solution requires a diet containing plenty of fibre.  The simple answer is to eat lots of fruit and vegetables and wholegrains (in eg. cereals and bread).  These foods tend to have a variety of other health benefits, including antioxidant effects (see below), so it really is worthwhile having your five (or more) a day.



Antioxidants are molecules that do exactly what it says on the tin – counteract oxidation in the body, a process that is more likely to occur when we exercise aerobically. They do this by mopping up harmful free radicals, the particles that are believed to cause mutations of DNA and potentially increase the risk of cancer and other diseases.  Foods that are high in antioxidants include green leafy vegetables such as kale and spinach (Popeye was onto something), fruits, carrots, whole grains, oily fish, seafood and lean meats, as they contain important minerals such as zinc, iron, magnesium and copper, and vitamins such as C and E.

Affordability and convenience

It’s very easy to give advice on what you should and shouldn’t eat. However, financial and time constraints can make it difficult to follow all the suggestions.  Healthy options are not always the cheapest options, and fresh fruit and vegetables, oily fish and nuts, for example, can be relatively expensive.  But you may find that beans of various types can be more affordable and can cover much of your protein needs.  Bananas, potatoes, rice and pasta are also usually relatively inexpensive, and remember that you don’t need much meat or fish in your diet to cover your protein needs, especially if you eat lots of beans, lentils, etc.  A breakfast including porridge oats is another cheap and effective choice. The thing is do what you can.  Any positive changes, however small, are potentially beneficial. For example, if your lunchtime cheese sandwich made with white bread is replaced by peanut butter on wholemeal bread, and you follow it with an apple or other fruit instead of a chocolate bar or biscuit, then that’s progress.

15 Replies to “Marathon diet plan – training phase”

  1. This is a great post. Thorough details about the marathon diet plan. For vegans, what are the alternatives for protein intake? Are lentils and quinoa enough or need to take any protein supplements?

    1. Hi Kavitha. Thank you for your positive comments. I’m not a vegan myself, though I have significantly reduced the amount of meat in my diet in recent years and feel I have benefitted. Beans and nuts are good protein sources, as well as quinoa and lentils, but clearly you need to monitor your protein intake (and the quality of your protein intake) if you are taking part in demanding physical activities, since muscle cells are constantly in need of repair. This link might be of interest.

  2. I really enjoyed dreading your post. Its extremely informative but speaks well tot hose who have no ideas about balanced diet (like me). I also think the bold words are a great feature to make them pop!. Keep doing what you are doing it looks great.

    1. Hi Russ. Glad you enjoyed the post and I hope it motivates you to make positive changes to your diet. Thanks for the feedback re the words in bold. It’s useful to know that they are effective in highlighting the key terms.

  3. I have enjoyed reading about different foods, as an ultramarathoner myself I was quite interested to see how you will deal with the meal plans as part of a training program. My experience is that many runners don’t understand their own individual fuelling needs starting from training up to the race day.

    The question of carbohydrates has been a subject of huge debate, until recently Professor Tim Noakes has been an advocate of Carbo-loading diet for marathoners, that has changed now to Banting Diet.

    I personally believe that a balance diet would still require a certain amount of supplements especially that healthy food is very expensive, so some of these supplements do provide nutritions which comes handy to a runner who can’t afford all the right food.

    Race simulation meal plan can be very tricky to a novice runner, in fact I have found that even veteran runners still struggle with this. There is indeed a huge scope to educate in this regard.

    Once again thanks for a good article.

    1. Hi Sphiwe
      Thank you for your positive feedback and your interesting and thought provoking comments. I will be looking up the Banting Diet and taking extra care to monitor my nutrient intake and keeping my mind open to the possibility of taking supplements where the need arises.

  4. It is a great post ! Recently i just started my workout routine at home, but i still miserable in my eating habits. I’m glad you sharing this for us. Let said now i just started my workout, how i going to change my working habits ?

    1. Hi Kendall. Glad you enjoyed the post and you are working towards a healthier lifestyle. Its not easy cutting out those unhealthy foods. As the boss of Gregg’s (a UK fast food food outlet) said recently on the radio, “If you offer people the choice of an apple or a donut for the same price, then the vast majority will opt for the donut”. The reason is of course that most people find the donut more appetising. So perhaps you need to focus on the positive benefits of the healthier diet to give you the motivation to make the healthier choice. This link gives a summary of these:
      Other suggestions are:
      Try to get the family on board – its hard to change your diet on your own
      Find treats that are healthy and appetising – for example, I love cashew nuts and pistachio nuts.
      Identify small changes you can make. For example, I used to often have three digestive biscuits with my cup of tea, but now I limit it to one.
      Identify particularly unhealthy things you do and try to reduce. For example, I would often snack on cheese when I felt hungry, and I wouldn’t bother cutting the fat off my meat. I still eat some fat and cheese, but its been moderated.
      Hope this helps. John

      1. Thank you for your information and suggestion. It is a good start when you are slowly changing eating habits. Massive changes towards eating might led us losing motivation and momentum. Step by step forward is the great foundation for us to accomplish our goals.

        Your reply is very helpful for me. Hope you creating more relevant content in the future. Wish you all the Best !

  5. Hey this is great knowledge, I have a question for antioxidants, which fruits have the highest level of antioxidants in them? I am trying to figure out what fruits to keep in fridge with antioxidants that are not too expensive

    1. Hi Carlton. Glad you found the post useful. As someone who likes to (and needs to) keep an eye on the budget, I get your question. It’s easy to find the best sources of any nutrient, but are they affordable? It’s probably safe to assume that any fruit will provide some antioxidants and other specific nutrients (plus fibre) that are beneficial to health, but berries, including blueberries, raspberries, blackberries and strawberries are believed to be among the best sources. These can, of course, be expensive, especially out of season (which is most of the time) but one thing to bear in mind is that blueberries, raspberries and blackberries can all be frozen, and I believe that freezing doesn’t affect the nutritional value. Indeed, I’ve read an article that suggests that freezing actually increases the antioxidant properties of blueberries. So what I will be doing is looking out for the bargains (buy one, get one free etc)and stocking up in the freezer. Also, in the late summer, I will be out blackberry picking with renewed vigour, knowing we don’t have to consume them all within a few days.
      Apples are also regarded as a particularly good source of antioxidants, but again you need to look for the bargains, as they can be surprisingly expensive, and they can’t be frozen, unless they are stewed (cooking apples), which is not a bad idea as they still provide antioxidants and other nutrients in this form. Red grapes, plums and prunes are other good sources. We regularly add tinned prunes to our porridge and these cost 80p a tin from a major UK supermarket.
      If you’re interested in vegetables, then kale, spinach, broccoli, pumpkin, carrots and beetroot are good sources that are hopefully affordable.

  6. I really enjoyed all the nutrition information you provided in your article for marathon runners, I am always interested in healthy diet plans to give me new ideas foods I can add to my diet that are healthy for me.

    When you can’t consume gluten are there foods you can recommend instead, I really have problems with even gluten-free grains so how can I overcome this problem


    1. Hi Jeff. Glad you liked the post. I tried going gluten free a couple of years ago because I had read some articles that suggested it might improve my athletic performance, but found no significant benefit, and certainly not enough to warrant the hassle and extra expense. However, if you have been diagnosed as coeliac then that is a different scenario altogether, and one which I don’t feel qualified to comment on. This link to Coeliac UK gives an extensive list of gluten free food sources that you might wish to try out, along with other information that you might find useful.
      Good luck!

  7. Awesome post! Got an overall grasp of how a foundation should like from a nutrition standpoint when training.

    Although, let’s take an athlete or a person who’s training, eating well and putting the most critical nutrients to his body naturally. Would you recommend taking supplements in general to enhance and cover any holes in your diet in general?

    1. Hi Julius. Glad you liked the post. As an enthusiastic amateur athlete, I personally don’t feel the need to take any supplements, providing I am able to achieve something approaching what I see as the ideal diet as outlined in my post. However, in the real world, financial, time and other restraints might mean that there might be some gaps, and if you can identify these gaps, then it might well be wise (and economical?) to fill them with supplements. For example, if you are unable to eat oily fish on a regular basis, perhaps for economic reasons or because you are a vegan, then maybe an omega 3 supplement might be a good idea. Vegans or vegetarians might also need to supplement their B vitamins as well as monitor their protein intake. All of us who live at higher latitudes might want to consider vitamin D supplements in the winter months (although climate change means that I can train in shorts and two t-shirts for most of the year now, so the lack of sunshine exposure isn’t such a big deal these days).

      If I were responsible for the diet of an Olympic hopeful, where small margins can be crucial, then I might be more rigorous about this and leave nothing to chance. But even then I would doubt the wisdom of giving supplements unless there was a clear deficiency of that nutrient in their diet or some problem was diagnosed (eg. iron or calcium deficiency).

      I’d be interested to hear your views on this question, and anything related to it.


Leave a Reply

Your email address will not be published. Required fields are marked *