Flavour of the Week / Practical Practice

Nutrition for a F.A.S.T. Marathon – Part 2

Nutrition is one of the key components to performing well in a marathon or any ultra-flavour-of-the-week-logo3endurance event. To optimize athletic performance, there are an overwhelming number of nutrition factors that have an impact – these F.A.S.T. nutrition tips can help summarize key principle to consider streamline your focus.

Last week we posted on Foods and Antioxidants and this week we follow-up with part two looking at Supplements and Timing. We recognize that the food you eat is of primary importance but there is more to it than just what you eat. It’s also when you eat which types of foods that can make or break your race. We also address those occasions where “normal” food may not be enough.


Vitamins, minerals, and fatty acids. The majority of these supplements are unnecessary for marathon runners IF the runner is healthy. If a health professional has determined that you have low levels of vitamin D, calcium, iron, etc. and has recommended supplementation, please follow their advice!

We would recommend that young, female endurance athletes have their iron levels checked and monitored. Only take iron supplements if your levels are low, as they can be quite toxic. For more information of dietary sources of iron, click here.

fish oil supplementOmega-3s
If you really hate fish, an omega-3 supplement can provide the missing omega-3 fatty acids. Importantly, though an omega-3 fatty acid supplement will not provide all of the nutrients found in fish. For more information on dietary sources, click here.

Vitamin D
A deficiency of vitamin D is thought to be common in the general and athletic populations. In athletes, a vitamin D deficiency has been proposed to increase the risk of stress fractures, respiratory infections – due to poor immune function – and muscle injuries (1). The research on the benefits of vitamin D supplementation on athletic performance though is still unclear and can be contradictory.

One study randomized club level athletes into either a placebo, 20,000 IU/week, or 40,000 IU/week for 12 weeks. At baseline, 57% of the athletes were vitamin D deficient and both treatments were successful at brinfing blood levels of vitamin D into the healthy range; however, no differences in muscle function – as determined by the bench press and vertical jump – were noted with supplementation (2). Conversely, another study found improvements in 10 m sprint times and the vertical jump with a 5,000 IU/day vitamin D supplementation over 8 weeks and no improvements in the placebo group.


Regardless of the contradictory results on physical performance, both of these studies agree that at Northern latitudes (all of Canada and most of the US) a significant number of athletes tend to be deficient in vitamin D. Therefore, it seems reasonable to suggest a supplementation of 1,000 IU/day. This is in accordance with the recommendations of the Canadian Cancer Society and is well below the upper limit of 4,000 IU. For more information on dietary sources of vitamin D, click here.

Vitamin C
orangesVitamin C supplements can be helpful for athletes fighting a common cold. A Cochrane review combined five research using endurance athletes, including marathon runners, and found a reduction in the relative risk of developing a cold with vitamin C supplements (3). Most studies use a dose of 500 – 1,000 mg/day; note: taking more than 2,000 mg/d can cause gastrointestinal side-effects. There is significant individual variation, however, so if you notice problems back-off the dose. For more information on vitamin C and where to find it in food, click here.

B Vitamins
The B vitamins are another area of interest for athletes. The general consensus is that exercise increases the need for the B vitamins because they are required for energy production and to make new cells. However, as athletes also have increased food intakes, they should be able to meet these higher needs through food sources; supplements should not be required if they are consuming adequate calories and a healthy diet (4).

Vitamin B12 supplements may be recommended for those over the age of 50 years or those who are following a vegan diet. Low vitamin B12 can lead to anemia and negatively impact performance. Although data on Canadian master’s athletes is not available, it has been reported that 28% of Canadians between the ages of 65-79 years with anemia have insufficient vitamin B12 levels (5).


When you eat can be just as important as what you eat. It’s important to have a tried, tested, and true nutritional strategy for your races and long runs.

Every Day
Every meal is important but the most important meals will be what you eat before and during your run. After is likely less important unless you have a hard workout planned for the next day. For your day-to-day workouts, as long as they are short (around one hour) extra-special planning is not required. Make sure you eat close enough to your workout (within an hour or two) so that you have enough energy to exercise efficiency BUT not so close to your workout that you don’t have time to digest and end up with stomach problems. If this is challenging, a sports drink containing fluid and sugar should tide you over.

Long runs and race day are a different story…

The Day Before
For the best results don’t just consider the meal before but the whole day prior, especially if your run is scheduled to be early in the morning. Focus on consuming sufficient fluids and carbohydrates as these are what will limit your performance. I find I have the best results when I step up my eating (a bit) the day before. Keep in mind that there is a lot of individual variation, and what works for others may not work for you. I often find that I can put on a couple of pounds the day before a long run if my glycogen (carbohydrate stores) and fluid levels are optimal. DON’T worry the weight is always gone by the end of the run!

If eating before exercise doesn’t agree with you don’t give up. Although I’ve not seen much scientific evidence, anecdotally you can train your body to cope with food prior to and during exercise. Play around with slightly different timing and different nutritional options. I bump up the complex carbohydrates with some pasta, rice, potatoes, yams, bread or other grains the day before.  I also add in a bit more fruit. This does not need to be extreme. Try to increase the carbohydrates primarily by changing the foods you eat rather than adding in large amounts of extra foods to avoid an excessive caloric intake.

Foods to limit: There are foods that are typically considered healthy that you might want to limit the day or two before. Anything high in fibre can cause gastrointestinal discomfort. Watch your intakes and know your body’s response to grains high in fibre (like bran), legumes, and fruits and vegetables high in fibre. You might also consider your body’s response to dairy products, anything high in fat, and spicy foods; as these are common “trouble” foods.

Fluids: Drink but remember you are not a camel in the desert! Drink to ensure you are well hydrated up to about 4 hours before. That will give your body time to get well hydrated but also allow you to pee out the excess so you don’t have to stop every 3km. During exercise drink as you are thirsty and as you can tolerate. If you commonly end up with headaches after your run then chances are you are not drinking enough.

If for whatever reason you haven’t been able to prepare as well as you would like, you can minimize any negative effects on your performance by carefully choosing your during exercise nutrition.

During Exercise
You will not perform optimally subsiding only on water during a long workout! You need sugar and electrolytes as well. A sports drink can work for shorter workouts, for longer I find solid food like a sports bar or gels are required. In either case – food or gels – need to be taken in small amounts and with water to avoid stomach problems.



In our experience, taking a full gel all at once can be problematic and better results seem to come from spacing out the sugar. Pre-mixing them with water and taking a bit a time works well. If that isn’t an option, consider taking half the get and then the rest half an hour later. The sport gummies are great for getting a more even sugar intake, as you can take a few at a time.

The “sport” foods are not required; they just tend to be easiest and what is available at the feed zones. You can definitely get away with regular, easily digestible, high-carbohydrate foods especially if your exercise is a lower intensity. The final piece of advice is to start early! It’s best to start fueling before you are tired within first 45 minutes. Waiting too long means your glucose levels have started to drop and makes it harder to catch-up later.

If your nutrition is well planned you should be able to keep on keeping on and enjoy the run!


  1. Agneline, ME. (2013) The effects of vitamin D deficiency in athletes. Am J Sports Med 41(2):461-4.
  2. Close, GL. (2013) The effects of vitamin D3 supplementation on serum total 25[OH]D concentration and physical performance: a randomized dose-response study. Br J Sports Med February 14 epub ahead of print.
  3. Hemila H et al (2013) Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev Jan 31;1:CD000980. doi: 10.1002/14651858.CD000980.pub4.
  4. Rodriguez NR et al (2009) American College of Sports Medicine position stand. Nutrition and athletic performance. Med Sci Sports Exerc 41(3):709-31.
  5. Copper et al (2012) Iron sufficiency of Canadians. Component of Statistics Canada Catalogue no. 82-003-X Health Reports. 

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