As a scientist in a previous life I am intrigued by the new vogue in DNA testing for fitness and nutrition. I was delighted therefore when Craig, my ex-PT, who was visiting from Australia, brought a kit for me to try. Craig has been using DNA analysis with his clients back in Sydney to help customise training and nutrition plans 

The reasoning behind the tests is that by identifying particular genetic variants in an individual’s DNA an optimal diet and training programme can be devised. A programme that plays to the individual’s (genetic) strengths. Among the areas investigated are:

 Sensitivities to the major food groups

 Effectiveness of metabolising micronutrients

 Ability to respond to different types of training 

Genetic predisposition for specific injuries and disorders

Responses to stress and ability to sleep

Predisposition to obesity

The Test

There are many different brands of DNA analysing kit available for sale. The one I used was Profit ( DNAfit ) which can be purchased online with prices starting from £89.  This is a simple test to perform. It consists of a mouth swab with clear instructions and onward packaging.  I did my test, sent it off in the post and eagerly awaited my results. It took just over a week for the analysis to be completed. When the report arrived it was in a very accessible format and made interesting reading.

However before discussing some of my results there are a few points worth keeping in mind. 

DNA testing for Fitness and Nutrition – Provisos

As with most things scientific, the “science” of DNA testing turns out to be something of an art. In my research I found a few articles written by people who had completed tests from more than one company and got some conflicting results. 

This is probably inevitable as what are determined are attributes/characteristics that in most cases are influenced by a collection of genes working together. For example, the test report on carbohydrate sensitivity considers six different genes that are known to influence this characteristic.  

The exact number and combination of genes influencing any one particular area might well be up for debate, and even when using the same genes the interaction between them can be open to different interpretations. It is not straightforward.

Even with the genes that are present, there appears to be another consideration as to whether certain genes can be switched on or off. 

Finally, whatever the genotype for a particular characteristic is, in most cases the environment can and will influence the expression of that characteristic too. There is a good example of this in my own results regarding sleep.

The company themselves do stress that the genes are only a part of the picture and that we are all a unique interaction between our nature and nurture – our genes and our experiences. It is suggested that knowing what is in our nature can help us decide on the correct ‘environment’, be it diet, training programme, or what time we choose to work, to best fulfil our potential. 

DNA Testing for Fitness and Nutrition – The Results

So with those provisos what did I learn from my results?

The report is split into six sections covering  Diet, Fitness, Stress/Sleep, Nutrients, Obesity and Bone mineral density. 

I will give a few examples of what my report told me. The most interesting results came from the diet section. So I will start there.


Apparently my genetic make up suggests that a healthy diet for me would be low in carbohydrates and high in fats. My genes indicate that I have a high sensitivity to carbohydrates. A diet high in carbohydrates would most likely result in higher blood sugar than ideal. At the same time I have low sensitivity to fats. The way my body absorbs, transports and metabolises dietary fat suggests that fats – and in particular unsaturated fats such as those found in avocado, fish, oil, and nuts – are good for me.

My current diet is very high carbohydrate and low fat. I have been aware of this being more so as time goes on.  It is true, however, that I have been having problems with my digestive system for some time. Often feeling uncomfortable after eating – not finishing meals but then feeling hungry and snacking.

The suggestion is that my ideal diet should consist of 25% carbs, 45%+ unsaturated fats, 10% saturated fats and 20% protein. Time for a change perhaps?

Interestingly, the report confirmed my experience that people with my genotype seem to respond better to the performance-enhancing effect of caffeine during work outs!


In terms of nutrients the report suggests I need to take care to get plenty of B6 and Vitamin D, as my ability to absorb these nutrients is poor. I have previously tested low for Vitamin D and already have it prescribed from my GP. 

B6 is necessary for the synthesis and breakdown of proteins in the body and is involved in the production of red blood cells and neurotransmitters. Insufficient levels can lead to low energy and a poor immune system, and can result in anaemia. Wholegrains and fish contain B6. Supplements are also suggested as an alternative. The report gives a precise amount of B6 required and suggests ways that this can be added to my diet.


Moving on to fitness: as might be expected, I have very high endurance and average power response. This puts me clearly in the longer-distance events rather than sprinting arena.  My strength response was low but I am told I must not neglect this area. Frequent reps with lower weights are recommended and shorter intervals with longer rests. I do keep promising myself that I will get back to the gym.

More good news is that I have high aerobic trainability i.e. my VO2 max will improve in response to exercise.  High intensity workouts and interval training are suggested. However what did surprise me was I apparently have a low recovery from exercise.

It has certainly been noticeable that my recovery has taken longer as I’ve got older but would not have thought this to be the case 5-10 years ago. I assumed that my ability to run back-to-back marathons or weekly races was because I recovered quickly.

The suggestion is that I leave 48 – 72 hours between hard workouts. I am forced into this position now as it is, but had seen this as an age-related thing.

The report goes on to give more detail about my fitness characteristics and suggests how to schedule my training based on these findings. I think that it was useful – more in terms of confirming what I had already worked out for myself. 

Sleep and Stress

The Sleep/stress section was interesting. It was comforting to know that I respond well to stress – in fact is there a suggestion that I actually need stress in order to perform well. Is this why I can’t pack a suitcase for a trip until the last minute, I wonder?

I have a tendency to be a night owl – hmm, yes of sorts, but then I do often fall asleep if I watch T.V. in the evening. And I’m good at getting up and functioning before dawn for races such as Comrades.

The truth is I don’t sleep much at any time so the biggest surprise of all on the report was that I should be a moderate sleeper. Not many people who know me would recognise this.

This must be an example of where my environment has influenced my genotype. To put it simply I don’t do sleep very well. I function on very few hours sleep a night  often reading / writing / thinking until dawn. It doesn’t seem to affect me in the morning as long as I have had some quiet time.

I assumed this was a learnt response. Both my parents were shift-workers with comings and goings in the house early and late. On top of this was the presence in the house of a fire-bell. A huge bell connected to the local fire station which rang day and night to alert my father, an auxiliary fireman, whenever there was a fire in the town. This would happen a number of times a day (or night) at least. Sleep was often interrupted. In another life I might have slept well.


I have given just a few examples of the results I obtained. 

The report itself is fairly long and comprehensive. It is full of information and advice. Each section makes suggestions for appropriate action based on the results found. 

Has it been useful? 

It has certainly confirmed many things I already knew and has given me some possible insights into areas I have been struggling with. I plan to make a few changes in training and nutrition  based on the report. It will be very interesting to see how this goes.

Overall the report left me feeling quite positive and I found it quite empowering that there may be, even at my age, actions I could take to try to help my genes along. For anyone who is interested I would suggest you give it a go but don’t take it too much to heart. Who knows were the true balance between nature and nurture lies.