Exercise and food intake Available to Purchase

One of the tools essential to the nutritionist's science is the measurement of food intake. However, this is an extremely difficult measurement to make. Garrow has made an analogy with Heisenberg's Uncertainty Principle in quantum mechanics. If you try to estimate the position of a particle precisely, it is not possible to measure its velocity with the same degree of accuracy, and vice versa; if you precisely measure its velocity you can be less certain about its exact position. The same is true of food intake; you cannot measure habitual behaviour accurately. You either have to measure habitual behaviour with a high degree of inaccuracy or make accurate measurements of food intake which may interfere with habitual behaviour. Any system which purports to be non‐invasive and does not disturb the subjects' lifestyle will be prone to errors of memory, recording or judgement of portion size and content.