Food Quantity and Quality
I love marathons. It’s a goal I have huge respect for. I get asked a lot about eating for a marathon and recently sat down with a nutritional scientist to put together a few basics on eating to prepare for the goal of a marathon.
Are you eating enough?
Adequately fueling your body is so important when it comes to training. Under-eating during heavy training periods can lead to a number of negative physical problems. We need to make sure we are consuming sufficient calories (from food and drinks) to offset our energy expended on exercise.
There are a whole host of online calculators you can use to estimate your energy requirements. They are never going to be 100% accurate so it’s important to monitor your weight and performance and adjust your intake as required. Don’t over depend on what a calculation tells you, monitor how you feel with the amount you are eating.
I think that for most people counting calories and tracking food can be more hassle than it’s worth, especially if you are trying to fit in training around work. Instead, I would keep a food diary to track your intake and to highlight areas you could improve on. I would focus on getting in three good meals and 2-3 snacks plus extras on training days if needed.
It’s important to consider macro-nutrient intakes; this refers to the amount of protein, fat and carbohydrates you are consuming.
As an athlete your protein requirements will be higher than the general population but you can still meet them through a normal balanced diet. General guidelines would be 1.2-1.4g/kg/day for distance runners. My advice would be to spread your protein intake over the course of the day and to aim for 25-30g at each meal; that’s roughly equivalent to one chicken breast,one salmon fillet, three eggs, 300g Greek yoghurt or one scoop of whey protein. Getting enough protein into your diet can help increase muscle recovery; repair muscle damage; increase adaptations to training; increase performance, and support immune function.
The evidence suggests that for sports — a higher CHO diet helps to replenish muscle glycogen stores and promote optimal adaptations to regular training. The recommendation for carbohydrate intake for runners is between 5-10g carbohydrate/kg body weight/day. The advice would be to aim for 1-2 cupped handfuls at each meal and then top it up with snacks as needed. Aim your diet around slow release versions like oats, potatoes, brown rice, quinoa and wholemeal bread and use quick release versions around training sessions and races and top up your intake if needed.
Fats are essential for optimum health and performance. They help to maintain a healthy immune system, produce recovery hormones and can act as a fuel source for lower intensity and longer duration exercise. Low-fat diets (<15% of your total calorie intake) are not advisable long term. Aim for a 1-2 thumb-sized portions of fat at each meal and two portions of oily fish per week. If this is not achievable for you then a fish oil supplement may be advantageous.
Are you eating good food?
While eating enough food is the primary issue when it comes to sports performance, the types of foods you eat are also important. Base your diet around whole foods that are rich in the vitamins, minerals and fibre your body needs to function at its best. Aim to fill half your plate with vegetables and try to incorporate as much colour as possible. I often get asked about multivitamins and while it may be beneficial for those in calorie deficit or with poor dietary quality, the evidence suggests they do not improve strength or endurance performance.
Hydration is an important factor and can be considered under three headings:
Before an event:
Drink enough fluids the day before and the morning of the marathon to ensure you are hydrated, about 300 – 500 ml water/isotonic drink before the race should be sufficient. Monitor the colour and volume of your urine as a measure of hydration status; if you are passing less urine or the colour becomes darker than normal, then you may not be drinking enough fluids.
During training, you lose fluid through sweating. If these fluid losses are not replaced by drinking, you run the risk of becoming dehydrated, which can cause fatigue and impair your performance. Fluid requirements are different for everyone but as a general guide, for runs lasting less than 60 minutes, water should be sufficient and for runs longer than 90 minutes an isotonic sports (Lucozade sport or homemade version) drink may help to replace fluids and provide a source of carbohydrate during longer runs. Aim to drink 100-150 ml every 15-20 minutes or at a rate that is comfortable.
Aim to replace fluids and electrolytes by drinking fluids slowly over the next 24 hours. Milk can be a great option post workout. Also, ensure you have re-hydrated before consuming alcohol after the race.Once you have your food quantity and quality in order you are well on the way to having a solid base to your training nutrition.