Nutrition During Training
Nutrition plays a crucial role in the life of an ultra runner. Without eating enough of the right kinds of food you will not be able to sustain the levels of training needed to reach your goals. This article is aimed at nutrition during training, rather than race day nutrition. Here are a few key points:
- The feeling of hunger is your body crying for nutrients. This includes more than just carbohydrates and protein. By eating highly nutritious foods you will find that you do not need to eat as much.
- The best source of nutrition is fresh organic fruit and vegetables. Greens in particular are the ultimate match for human nutritional needs. If you can eat plenty of organic greens each day you are on the right track to optimum health. Have them blended in a smoothie or lightly steamed. Eat a range of fruit and vegetables to get all your vitamins and minerals. Although organics are more expensive they contain on average more nutrients and less pesticides and other toxins. So you do not have to eat as much.The best place to buy organic fruit and vegetables is at local farmers' markets.
- During endurance exercise your main source of energy will be fat. Be sure to include healthy fats in your diet such as olive oil and flax seed oil.
- If your body uses up all its carbohydrates during prolonged exercise then it will start to break down protein from muscle. Be sure to eat enough carbohydrates. The best sources of carbohydrates are unprocessed, natural foods such as fruits, starchy vegetables and whole grains.
- If you eat enough natural whole foods you are probably meeting your protein needs.
The following provides an overview of the main food groups.
Carbohydrate provides the energy that fuels muscle contraction. After digestion carbohydrate is broken down into smaller sugars – glucose, fructose and galactose – that can be used immediately for energy. Any glucose that is not needed is converted into glycogen and stored in the muscles and liver.
If there is not an adequate supply of carbohydrate then the body will break down protein to use for energy. Obviously this is an unfavourable situation as protein is needed for tissue growth and maintenance. In addition, protein breakdown puts stress on the kidneys due to the waste products released. So as an ultrarunner it is essential to be taking in enough carbohydrate to stop the body using protein as an energy source.
Carbohydrates can be measured in calories. The amount of calories used during exercise depends on the pace you are running at and your body weight, ranging from 500-1000 calories per hour. If you weigh 70kg and run for 2 hours at 9 min mile pace, you would use about 1500 calories. 1 boiled potato provides 120 calories, 1 cup of cooked spaghetti gives 190 calories. The amount of calories you use when not running depends upon your body weight and what kind of work you do, ranging from about 1500 to 2000 calories per day. You can work out your total calorie requirements here:
There are 2 broad categories of carbohydrates – simple and complex. Simple carbohydrates are sugars which are absorbed and converted to energy very quickly, but may also invoke an insulin response which leads to reduced blood glucose levels – the infamous sugar crash. Sources of simple carbohydrates are fruit and honey. Complex carbohydrates are long chains of sugar units. These require more energy to break down. The best way to provide the diet with complex carbohydrates is to consume foods in their most natural state such as oatmeal, bran and brown rice. Other good sources are whole grain breads, wholemeal cereals, pasta, beans, potatoes and lentils. It is preferable to eat whole fruit rather than drink fruit juice as the fibre content will slow down the absorbtion of sugar and deter glucose highs and lows.
The maximum amount of carbohydrate we can store in our muscles is about 15g per kg of body weight.
Once the body’s stores of carbohydrate are full, any excess carbohydrate consumed is converted to fat. Basically, fat is produced when we consume more calories than we use. Although fat has a bad reputation in the food world as many people are trying to lose weight, it is the biggest source of energy in the body. In an event such as an ultra marathon it will in fact be the main source of energy. 1 gram of fat provides 9 calories, whereas 1 gram of carbohydrate provides only 4 calories. Breaking down fat and transporting it to muscles takes time, whereas carbohydrate is stored in muscle in a readily usable form. Breaking down fat also takes a lot of oxygen, so is not possible during high intensity exercise. But in longer, less intense exercise fat can be utilized as an energy source.
Aside from being a source of energy, fat provides cushioning for vital organs, covers the nerves and moves vitamins through the body. There is an optimum level of fat for health and activity. Too much can obviously be a hindrance.
Fats are generally divided into saturated and unsaturated. Saturated fats usually come from animal sources and are solid at room temperature. Sources include meat, egg yolks, butter, yoghurt, milk and cheese. This type of fat, over the last few decades, has been linked to high cholesterol and heart disease. However, more recent research is showing that some saturated fat is necessary and tropical oils such as coconut oil are beneficial to health.
Unsaturated fats are usually liquid at room temperature and come from vegetables, nuts and seeds. Examples are olive oil, peanut oil and avocado oil. These fats do not have associated health risks.
Protein is made up of long chains of amino acids. There are 22 different amino acids needed by the body, mainly for tissue growth and repair. 14 of these can be manufactured by the body, the remaining 8 must be ingested in the diet and are thus called essential amino acids (EAAs). Since most sources of protein do not have all 8 EAAs in adequate quantities, it is important to eat a range of different proteins. The amount of protein recorded on food labels only lists the complete proteins. A product may contain much higher amounts of incomplete protein that is not listed. Combining such products may increase the total amount of protein beyond the levels expected.
In general protein from animal sources is said to be complete, meaning it contains all essential amino acids. This includes meats, fish, poultry, cheese, eggs, yogurt, and milk. Plant foods (legumes, grains and vegetables) are said to provide incomplete protein because they generally lack some essential amino acids. Exceptions are quinoa and soy beans. However, it is not necessary to get all amino acids at the same time and by eating a range of grains and vegetables you can meet your protein requirements. There is an ongoing debate as to the best source of protein - animal or vegetable - which is beyond the scope of this article. An article from the Harvard School of Public Health concluded that the most important thing is what comes with the protein, ie.saturated fat. Although red meat is high in protein it is also high in saturated fat, so it is better to go with vegetable protein or lean meats.
Studies vary widely in estimating human protein needs. The standard recommended protein intake for an average person is 0.8g of protein per kg of body weight per day. Studies of athletes go up to 1.2g. But research done on traditional communities with very well established simple diets has shown that about 30g of protein per day is sufficient to maintain excellent health. If you are eating a variety of whole foods and meeting your calorie requirements, you are probably getting your protein needs too. Although endurance athletes will require more protein than the average person, they probably eat more in general than the average person and this should ensure they get enough protein. It should not be necessary to resort to protein supplements. There are some views that supplements are harmful since they are not a whole food so they oversupply the body with a particular nutrient and cause a deficiency of another. Excessive protein is also considered harmful as it overworks the kidney and liver and may also lead to dehydration.
4. Antioxidants, Vitamins and Minerals
During exercise, the body’s consumption of oxygen increases greatly, which leads to increased free radical production. A free radical is any atom with an unpaired electron in its outer shell. Free radicals are potentially harmful as they are highly reactive and tend to steal electrons from surrounding molecules. Commonly, free radicals will steal electrons from the lipid membrane of a cell, propagating a chain reaction which may result in muscle damage or an increased susceptibility to disease or injury. Under normal conditions the body is able to counter free radical production through its antioxidant defense system, but during prolonged exercise free radical production may exceed the protective capacity of the body. Although there are many antioxidants, the ones most commonly found in food and supplements are vitamins A, C, E and selenium. Good sources of antioxidants are cocoa, various berries such as blueberries and strawberries, red kidney beans, pinto beans and green tea.
The body needs 50 or so vitamins and minerals. The best way to get these is from eating a range of fruit and vegetables. Green leaf vegetables such as kale, spinach, parsley and rocket are a good match for human nutritional needs. As it is difficult for most of us to eat enough greens, there is a movement now favouring the consumption of raw greens blended with fruit - the so called ‘green smoothie’. More information and recipes are available here:
Dietary fibre is made of indigestible carbohydrate from plant foods. Aside from assisting regularity, fibre can help to balance blood sugar, lower the risk of heart disease and assist removal of toxins from the body.
Some foods are exceptionally high in nutrients. Not all of these are cheap enough to warrant regular consumption on a significant scale. Here are a few:
- Sea vegetables (‘seaweed’) have the highest percentage of vitamins and minerals of any food source. They have more Vitamin A than carrots and are also high in Vitamins B, C, D, and K.
- Cacao, the bean used to make chocolate, has the highest concentration of antioxidants of any food. It also has 10 times more magnesium and chromium than any other food. Magnesium is the most important mineral for health.
- Quinoa, an ancient grain of the Aztecs, is a complete protein source as well as providing 8 vitamins plus fibre.
There are many others that can be added to this list.