Improve your performance - Learn to cook

Seems so simple doesn't it.  Learn to cook and your performance will improve.  Well your health certainly will improve and with that comes a better ability to train and a greater chance of your body recovering between training sessions.  You learn to cook and the quality of your diet improves exponentially, and the quality of what you eat is key.

When you eat food there are a series of responses which go on in the body.  Your body produces heat in response to the digestion of the food you eat, scientists like to call this diet induced thermogenesis.  This takes energy to do and is an important part of your body functioning properly.  Depending on what you eat you will get an increase in the amount of sugar in your blood and the amount of fat too.  Too much sugar in your blood (called hyperglycamia) leads to "stress" on your body, similarly with an increase in fat (lipids in science language) in your blood, especially some of the saturated fatty acids.

Two newer areas which have been researched are the postprandial (after eating) response of your bodies antioxidant system and the inflammatory system.  You generally want your bodies antioxidant system to be in good working order and preferably not have too much inflammation. 

So lets take a look at these four areas and see how they are affected by processed food versus "homemade" foods:

Diet Induced Thermogenesis:  A lovely recent study by Barr and Wright from Pomona College in the USA looked at the effect of eating a processed cheese sandwhich on white bread versus cheddar cheese on whole grain bread.  There was a 50% increase in diet induced thermogenesis due to the "homemade" sandwhich compared to the processed food.  Now I now what your thinking.  Cheese and Bread doesn't sound too healthy or even homemade, but if even this small change can have such a big effect imagine what a proper homecooked meal would do.

Postprandial glycamic and lipid responses:  Generally processed food is full of processed carbohydrates and bad saturated fats.  These lead to spikes in blood glucose and lipids which lead to your body becoming over stressed.  If you cook food yourself it will generally be lower glycamic index and contain reasonable amounts of fibre which slows absorption and lowers the peak response in blood sugars and lipids.  There are also some nice ways to help your body cope with these postprandial responses, and they are called herbs and spices.  Cinnamon is particuarly effective in helping your body cope with nutrients you eat.  Hlebowicz et al. (2007) showed that just adding 6g of cinnamon to a rice pudding meal will reduce the post prandial glucose response .

Postprandial antioxidant status:  This is key to general health, as these support your immune system and will help you recover from the stress of training.  A lower glycamic index meal will have a greater response to your bodies antioxidant status, whereas high glycamic index meals will have only a small effect on the bodies antioxidant status.  We also know that fruits are particuarly good at increasing your bodies antioxidant capacity after you eat them.   

Postprandial inflammation:  This is quite a new area but is quite interesting.  There has been a large increase in research suggesting that diet can contribute to low grade inflammation which in turn can be linked to many chronic diseases such as diabetes.  From a sport performance perspective if you have a constant low grade inflammation you will not recover properly and are more likely to get ill.  Certain foods seem to cause large inflammatory responses such as alcohol, added sugars, other refined carbohydrates and saturated fats (sounds like a processed meal!!!).  Foods which decrease the inflammatory response to food include fruit, vegetables, milk, nuts, wholegrains and fish (sounds like homemade meal).  Arya et al. compared the postprandial inflammatory response to kangaroo meat versus a more processed meat called wagyu (the research was done in Australia!!!).  Various inflammatory markers such as IL-6, TNF-alpha and C-Reactive Protein were measured.  The wagyu meat showed significant increases in these inflammatory markers, whereas the kangaroo meat only showed a slight increase in these markers.  Therefore, buying good quality meat and other foods is key.  

So hopefully you are convinced that learning to cook will help your performance, it will certainly help your recovery and if you can do that you can train harder.  Saying you can't cook is not an excuse, saying you have no time to cook is not an excuse.  You don't have to cook gourmet food which takes hours.  Keep it simple.

Individualisation of nutrition

Have you ever heard someone say if I look at a carbohydrate I get fat, or similarly that they can eat anything and not put on weight.  I bet you have.  This fascinates me, how the same people can eat essentially the same diet and have such as different response to it.  The idea of an individualised diet is key.  I think sometimes nutrition can be set up as a one size fits all approach, this worries me and if you don't listen to how your body reacts to food you are missing a trick. 

Lets try and put some science into this.  The first peice of evidence I want to look at is the idea of predicting energy expenditure whether it be from heart rate, accelerometry or some other form.  You tend to get a graph which looks something like figure 1.

Figure 1 - Predicted energy expenditure

Now, science likes graphs like that in figure 1 because there seems to be a positive and pretty good correlation between the actual energy expenditure and the predicted energy expenditure.  This means you can get a nice equation which predicts energy expenditure from something simple like heart rate.  You can then use this to calculate how many calories you burned during exercise and subsequently how many calories you need to eat.

However, not everyone sits nicely on the line.  At an actual energy expenditure of 200 kcal per hour one indivdiual has a predicted energy expenditure of 100 kcal/hour and another 300 kcal/hour.  This means that over one hour of exercise the prediction has over estimated or underestimated energy expenditure by 100 kcal.  Now this might not seem a lot, but for an endurance athlete doing lots of training this could add up.  You could either end up putting on weight if your energy expenditure is over extimated or maybe not train properly if your energy expenditure is under estimated.

What about how you react to different nutrients.  A recent study by Pittas et al. 2006 looked at how healthy men and women reacted to either a high glycemic load diet (basically a high carbohydrate diet) versus a low glycemic load diet.  What was interesting was that one group of individuals lost more weight on a high glycemic load diet and another group lost more on the low glycemic load diet.  The difference between the group was how the hormone insulin responds to a carbohydrate load (called an Oral Glucose Tolerance Test (OGTT)).  If there was a high insulin response in the OGTT then the individuals tended to lose more weight on a low glycemic load, if there was a low insulin response then individuals tended to lose more weight on the high glycemic load diet.

So if everyone has the same diet they are going to respond differently and therefore what you eat should be individual to you.  General guidelines are a great starting place but don't forget to listen to your body