Nutrition Q&A: What should I eat before a half marathon?
With two days to go before my half marathon, I consult Solgar’s nutritionist Paul Chamberlain on what to eat before the big day. In this marathon nutrition guide, he covers everything from what to eat breakfast to how even just a mouthful of sports drink can make a difference to your running time and endurance.
Given that my life is generally sedentary (read: office-based) with a few exercise classes thrown in, I needed a little help in order to work out ho how much, and what, I should be eating before running a long race, with much more physical activity than I am generally used to. Here’s what he told me:
What’s the best breakfast to have before a long training run, and how long before the run should I eat it?
The scientific literature suggests anything between 1-4g per KG body weight of carbohydrate eaten 1-4 hours before a race – which actually isn’t very helpful! As with so much in exercise nutrition the pre-race breakfast is a really individual thing and experimentation in training to find what works for you is the best approach. Essentially you want to be fuelling on carbohydrate foods and the general advice is to try two hours before running as a starting point for your experimentation. Much of it depends on your digestive system, how fast you are going to be running and of course the types of food eaten.
Porridge is the classic runner’s breakfast and for many people it works really well. For other people beans on toast, or even eggs on toast can be great. Bagels are good because they have a really high carbohydrate content. Generally, I would say that the longer the time between breakfast and the start the more protein I’d add. So with four hours to the start eggs on toast would work well for example. Protein helps you feel full and satisfied, so adding protein might be more satisfying if you have a long wait until the gun goes off. Conversely if you have a really early race start and having breakfast 2 hours before the start is not practical, go for simpler carbs, which are easier to digest and turn into energy. Cornflakes for example, or white toast and jam, or a bagel with some fruit juice. If you are really late up even some sports drink or an energy gel will be suffice in an emergency.
Will I need more protein during training compared to my everyday lifestyle?
Protein intake requirements for sedentary people is around 0.8g of protein per Kg of bodyweight. So for a 70kg person that’s 56g of protein per day. Those who exercise generally need a little more to aid recovery and muscle adaptations. The amount depends on the volume and intensity of your exercise. For most recreational exercisers increasing protein up to 1.0 to 1.2g per Kg body weight is sufficient (70kg person would need 70 – 84g protein). For more serious endurance athletes protein intake requirements can be nearer 1.6g per kg body weight and above (112g protein for a 70kg person).
High quality protein can be derived from meat, fish, dairy products and eggs, and also by combining beans and grains (for example beans on toast provides all the amino acids required for complete protein). Protein supplements such as whey protein can be useful to supplement food protein sources, especially post exercise when the body is very receptive to absorbing and utilising the amino acids in protein for muscle repair. However, for most recreational exercisers training for a half marathon, food sources of protein should be sufficient.
As a 5″2 female running around 20 miles a week, how many daily calories should I be looking to get?
With running it is pretty easy to work out the energy cost because running costs about 115 calories per mile, irrespective of pace. So for 20 miles a week that is an extra 2300 Kcals per week, or 330Kcals per day. At 20 miles a week it is probably not something to worry about too much and 330Kcals per day deficit is an ideal amount for sensible weight loss. However, once that gets over 500 calories per day it can start to affect recovery.
Muscle repair and adaptations require energy, so undereating relative the amount of exercise you are doing can really hurt your recovery. Undereating can therefore contribute to overtraining syndrome. So over about 30 miles a week you need to be paying attention to how much you are eating to ensure you are recovering properly, even if weight loss is your goal. Undereating is one of the most common things I see when working with endurance athletes.
Should I be using energy gels? What length of run requires energy gels, and when should they be consumed?
The time taken to run a marathon generally exceeds the amount of time your muscle glycogen stores can fuel your muscles. Running out of glycogen results in hitting the dreaded wall. Technically, for a half marathon, glycogen availability is unlikely to be a limiting factor in your performance. However, there have been some interesting studies looking at something called carbohydrate sensing in the mouth. It seems that carbohydrate receptors in the mouth can influence regions of the brain that affect your perception of effort. So in studies where participants have mouth rinsed with sports drinks (but not swallowed them) their performance is improved. The practical take-home from this is that consuming sports drinks and gels, even in shorter races such as 10K and half marathon, may help reduce your perception of effort, and therefore help you maintain your pace until the end. I highly recommend swallowing them though. Spitting out your sports drink all over your fellow runners might be frowned upon!
For a more palatable alternative, you can technically use anything sweet. Jelly Babies are a classic mid run treat and dried fruit can also work well. Anything to give a sweet taste in the mouth is technically all that you need for a half marathon. At the other end of the scale ultra-marathoners have to become accustomed to eating all kinds of things on the run, with aid stations laying on a veritable banquet of sweet and savoury snacks. Again, experiment, find what works for you, and never ever try anything new on race day!