The idea of burning off unwanted excess body fat, through increased physical activity, seems so simple a straight forward. Furthermore, this theory is reinforced by the very definition of body fat, found in any human anatomical textbook : a reserve of lipids (fat) which can be oxidised (burnt off) to meet the energy needs of the body.
Unfortunately, the scenario illustrated here, far too often remains just that, an unattainable goal, no matter how much effort and time we invest.
Fit but Fat
When I was at the peak of my running fitness with a vo2max of 70 and running over 100 kilometers per week, I was carrying more body fat, than I do these days where I don’t run at all.
Because I got leaner with less physical activity, at an age where it seems to be an accepted societal belief to develop the ‘middle age spread’ as an inescapable result of aging and becoming less active, I naturally became eager to discover why this supposedly undeniable truth, did not apply to me, but quite the opposite?
Obtain and maintain ‘access’ to body fat
Body Fat : a reserve of lipids (fat) which can be oxidised (burnt off) to meet the energy needs of the body.
If we think of body fat as merely a stored energy source in the body, as long as the ‘vault door’ is open we can access it any time, whenever our body needs it.
As we sleep, we are obviously still using energy to stay alive and if our body is able to release it’s body fat into the blood circulation it can be burnt off as energy. In other words, if we can maintain access (keep the vault door open) to our body fat (energy) the burning of it will take care of it self, even if we sleep instead of exercising.
However should the ‘vault door’ slam shut, we have now been cut off from our largest energy storage. As we continue to burn off and eventually run out of our very limited sugar stores, it is inevitable that we will become hungry, because we simply don’t have access to our body fat as an energy source.
This analogy, may help to explain why exercise cannot be used as a stand alone intervention, if we are trying to lose weight (body fat). Performing more and more exercise in the hope of reducing our waistline, will simply use up our sugar stores more quickly, after which hunger will set in.
Watch my lecture on why weight loss (fat loss) is determined by diet rather than exercise.