Twenty First Annual Darwin College Lecture Series 2006
Lecture 6 : 24 February
London School of Hygiene & Tropical Medicine
Who amongst us has really been forced to contemplate the dark horror of the simple word 'famine'? Who amongst us needs to worry about where our next meal will come from? Yet to our recent ancestors the unimaginable horrors of famine have been an ever-present threat.
Food historians propose that hunter-gatherer humans were protected from famine by their very low population density, their dietary diversity, and their ability to migrate when local resources were depleted. Paradoxically it was the dawn of agriculture that heralded seasonal hunger and catastrophic famines caused by climatic instability. Huge populations dependent on a single staple crop could be devastated by drought or blight. And if they escaped the wrath of nature they could be scythed down by man's inhumanity to man when starvation was used as an instrument of war and subjugation.
Surviving famine has driven the evolution of a range of metabolic and behavioural adaptations. We overeat and lay down fat when the harvest is in; we stop breeding when resources are short; we suppress our metabolism to conserve energy; we steal and we covet our neighbours' belongings; and when famine is really severe we eat each other. In modern wealthy societies these responses are redundant and many have become maladaptive. The pandemic of obesity and diabetes is a classic example of 'thrifty genes' rendered detrimental by progress. Certain human behaviours might also be traced back to our ancestors' struggles against famine. We bear the mark of these struggles indelibly etched into our genome. As Darwin concluded in his Origin of Species '. the production of the higher animals, directly follows . from the war of nature, from famine and death'.
Andrew Prentice is Professor of International Nutrition at the London School of Hygiene and Tropical Medicine. He is also the scientific director of the MRC Nutrition Programme based around the rural village of Keneba in The Gambia, West Africa. He was born and bred in Uganda and has maintained a deep love for Africa. He trained in biochemistry and then nutrition at Darwin College, Cambridge. His early post- doctoral research was based in The Gambia and concentrated on the effects of protein-energy malnutrition on reproduction and child health. He then returned to Cambridge to lead the Energy Metabolism Group at the MRC's Dunn Clinical Nutrition Centre at Addenbrookes'. Here his group used a variety of state-of-the-art techniques (including whole-body calorimetry, and the doubly-labelled water method) to investigate the basic mechanisms regulating human energy balance. As the obesity pandemic started to gain momentum in the 1980s his research was inevitably drawn in this direction. By the late 1990s he had concluded that the main causes of obesity where environmental rather than genetic or metabolic, and decided to re-focus his research on diet-disease relationships in low income countries. In 1999 he created the MRC International Nutrition Group in London and in addition to the Gambia programme has collaborative projects in Pakistan, Bangladesh, Chile, Kenya, Zanzibar and South Africa. He has a strong interest in the evolutionary consequences of famine particularly as mediated through effects on human reproduction. His work has been recognised by a number of international awards including the Peter-Debye International Science Prize, the Gunnar-Levin Nutrition Medal, the BNF, FENS and SINR Medals, and the Edna and Robert Langholz International Nutrition Award. He is a fellow of Darwin College.