Testing Times - 'Why cant I lose body fat?'

Its been a really busy month with athletes racing all over the country and abroad.
The Triathlon season is well underway, Summer is now threatening some good weather and the never ending football season continues with the World Cup.

The reason I mention football is that in the last few weeks I have been doing a lot more metabolic testing from outside of the world of swim, bike and run.
That includes professional footballers looking to head back into pre-season training to mum's that want to loose a few pounds and get back into shape. I have done hundreds of these type assessments and always enjoy them as it provides me with a window into what's been going on in their training and nutritional habits. Patterns start to emerge in the data, from which you can start to understand what they have been doing and why certain things are happening.
'I am training really hard and I don't seem to be able to lose any body fat.' was a comment made to me by a client this month and its something that comes up regularly at these assessments. This is a really important issue if you are an aspiring athlete or age grouper because there is a close correlation between lower levels of body fat and high levels of performance, much closer than body weight and performance.
For top level male marathon runners the average body fat is around 6%, in pro triathletes 7% and in sports like rowing and football 8/9%. Its also much better for your health to have lower levels of body fat, it cant have escaped our notice that obesity is linked to hundreds of illnesses. So why do so many of us find it so hard to lose body fat? Studies tell us there are a number of factors involved, here is what I have noticed and some of the advice that I am giving to clients that want to make changes.
The first assessment we look at is resting metabolic rates (RMR) this helps us understand how many calories a client needs to eat to maintain, gain or lose weight. So let's say my resting metabolic rate assessment suggests I need 2500 calories per day to maintain my body weight. Clearly if I exercise, burning a further 1000 calories my daily calorific requirement go up to to 3500 calories. If I eat less that 3500 calories over time I am going to start to loose weight, but this needs to be done cautiously and slowly to let your body adapt. Sometimes I have seen very low RMR calorie requirements(below 1000) and this is usually a sign that the person has gone on some type of fad diet or just is not eating enough. As counter intuitive as it seems sometimes you need to eat more to lose body fat. If we eat to little the body triggers a survival mechanism and starts to store fat, our bodies need a certain amount of ready carbohydrate to burn fat. This will also have a very negative effect on our ability to recover from workouts, we will be carrying fatigue over from sessiont to session and this can eventually end in illness or injury.

The assessment also tells us how efficient in percentage terms the body is at burning fat and carbohydrate (glycogen). Its no suprise that clients that find it harder to lose body fat tend to have a lower fat burning percentage and this means thier body is used to burning higher levels of carbohydrates, so fat stores are not being utilised, this even happens with endurance athletes. Carbohydrate is a faster fuel source for the body than fat, the more intensely we work the more the body turns to carbohydrate for its fuel. I have also noticed anecdotally that the less efficient carbohydrate burners report more hunger pangs, sweet cravings, swings in mood and reduced concentration. Not too suprising as burning high levels of carbohydrate is going to effect the blood sugar balance to a far greater extent.

As far as training is concerned if I see a low percentage of fat utilisation I usually find that translates to an under developed base level of fitness. For whatever reasons they have missed or skipped the base building fitness phase and are used to working at quite high intensities. This does not means to say they are unfit but they are limiting the level of absolute fitness and performance they can achieve without the level of efficiency a solid base can bring. This is normally confirmed when we do the second exercise based Vo2 assessment and we can see a big gap between the predominent fat burning heart rate zones and the clients higher carbohydrate burning anaerobic threshold.
Where I see this pattern emerge the usual advice I give to clients is simple, include back in the training programme longer lower level heart rate work outs and include some strength training to maintain muscle mass and encourage fat metabolism. Seems like a simple answer but the question I posed earlier is why do so many of us find it so hard to lose body fat? Apart from any nutritional issues (that I will come back to in the next post) The feedback I get back most regulaly from clients is 'I find it really hard to run or bike that slowly to keep my heart rate down' This is less likely to be a phyiological issue, this is more often than not a pattern of behaviour that has been developed through training with friends that get too competitive or just a preference to train at a level where 'If I dont train hard I don't feel as if I have done a workout'. Maybe this is where we need to place our focus if we are going to start to see some different results!