A Question of Dose

Abstract

Paracelsus is famed for his musings on the importance of using the right dose to achieve a beneficial effect, and he is not the only one to have realised that there can be too much of a good thing. Since the beginning of human time, obesity has been linked to the inappropriate dosing of food, and calories have taken the majority of the blame. This principal is based on the laws of thermodynamics: energy cannot be created or destroyed so fat has to come from somewhere and nutrition is the main route in. However, the global epidemiology of obesity suggests that the biological system, although bound by these laws, is not as simple as once believed. First, the effect of dosing is disproportionate, with the beneficial result obtained from a dose somewhere in between an ineffective shortfall and a poisoning excess. Second, in a biological system the influence of dose is affected by many other factors – genes, environment, diet and lifestyle, for example. The dose is not only dependent on the individual, but also on their age, health, physical activity and even their body weight. The complexity is such that people of some nations remain trim on a higher energy intake than those of other nations who, despite eating less, are weighed down with adipose tissue.