Food For Exercise By Ian Marber -Independent nutrition therapist and health writer

There are few areas of nutritional science as hotly debated as nutrition for exercise, largely because of the many variables ranging from type from the type of exercise undertaken to time spent.         

The requirements of a 100kilo adult engaged with powerlifting won't be the same as a 60k long distance runner, which in turn will differ from someone who goes to the gym three times a week. 

For those of us that aren't professional athletes, football or tennis players, sport nutrition can be overwhelming. That can be off-putting for the layman, but as that includes the vast majority of people who exercise, will food be enough and if so, what should we eat. 

There are two areas here; firstly, what to consume to enhance performance, be that strength or endurance and secondly, to improve the results of exercise, which may mean stamina or muscle tone

Starting with food

What we eat is broken down to create glucose, which is then fed into cells that contain mitochondria, tiny powerhouses that produce energy. There are anywhere from a few to several thousand mitochondria is a cell and numbers increase when demand rises. In other words, physical activity will lead to a jump in the output of energy as demand increases supply and so the most efficient way to improve performance is activity itself

Simple carbohydrates are broken down rapidly whilst complex ones take a little longer. Therefore, a fast source of fuel can be derived from sugars, refined flours and grains, but it is generally short lived. Medium term energy comes more easily from complex carbs, rich in fibre, as they take longer to break down. Eating a fibre-rich grain results in a slower yet more consistent source of fuel – think of as drip-drip-drip rather than the ‘whoosh’ of simple carbs

Any extra glucose that is not being used is stored as glycogen, which effectively forms a small yet important store of fuel – think of it like an overdraft facility, jumping in when fuel/money is tight. Together with circulating glucose this underlines how carbohydrates form the basis of energy for speed and endurance.

Protein on the other hand, forms the basis of strength and muscle mass. Protein contains amino acids, the building block of muscle and tissue, and so eating protein can enhance both tone and size if done correctly.

1. Simple carbs are most useful for short term bursts of energy, such as sprinting or high intensity training.  Sports drinks containing glucose and/or caffeine are common, but one can also have juice, coffee, soft fruit such as a banana or a smoothie. 

2. Exercising on an empty stomach doesn't necessarily mean that fat will be released to make energy, as adrenaline can step in, causing gluconeogenesis, a process in which the liver actually makes glucose.

3. Protein is the most important macronutrient in terms of exercise, so much so that the European Food Safety Authority approved three claims about it – that protein helps maintain and grow muscles and also that it contributes to bone health. A moderately active adult needs 1.3g per kilo of bodyweight whilst a very active one needs 1.65g.  Bear in mind that a large egg contains 6g of protein, a 100g chicken breast contains 29g and 100g of salmon offers 22g of protein. 

4. Caffeine pre-exercise can enhance performance and intensity of exercise, more so if you aren’t a regular user. 

5. Post weight bearing exercise have at least 10g protein, either through food or protein shake, with a form of carbs to enhance entry of amino acids into muscle. 

Disclaimer: 
Food supplements should not be used instead of a varied balanced diet & healthy lifestyle.