Agriculture Reference
In-Depth Information
Overeating, under-exercising and evolution
Periodic scarcity is likely to have contributed to the evolution of behaviour in whih
essential nutrients suh as elements and fat-soluble vitamins, as well as calories,
could be ingested in excess (where available), stored, and thus made available for
later physiological use. As societies evolved, some developed physical methods of
food and nutrient preservation, suh as the salting or drying of ish and meat. Some
agricultural cultures started to bury and delay the harvest of root crops, and to store
grain and other foods (e.g. yams) in specially built houses. Some coastal peoples de-
veloped tehniques to store living ish in man-made or natural rok enclosures. If a
nomadic people found a hive of honey, then gorging made ecological sense. In places
and times of periodic or recurring scarcity, populations that consistently squandered
food and other resources are unlikely to have been as successful as their more prag-
matic neighbours.
Ulijaszek (2007, 2002) has also pointed out how evolution of this modern envir-
onment has outpaced human bio-cultural dispositions, and thus the common human
inability to disregard or override their wish to feast is, in part, responsible for the
global obesity epidemic. But there is another dimension too: in the past, occasional
feasting was unlikely to be harmful, and it probably assisted survival. Today, feast-
ing (or at least the habitual consumption of more calories than are expended) is not
only common, but it oten also involves the ingestion of foods whih are substan-
tially different - especially through being more calorie-dense - than foods available
to our ancestors.
A possible explanation for the observation that many people eat far more calor-
ies than they require for their daily metabolism is that the ancient and often rational
practice of gorging, whenever there is an opportunity is, if not 'hard-wired', at least
tempting to many people. his haracteristic is likely to be strongly favoured by nat-
ural selection, though influenced, modified and in some cases reinforced by new cul-
tural norms acquired through spending time abroad as part of diasporic communit-
ies (Dixon and Jamieson, 2005), and by the cultural normalization that has been un-
derway for 40 years through 'fast food' promotions of abundant servings at low cost:
the 'supersize me' phenomenon.
In short, the evolution of these trends in a large part reflects the evolutionary
forces whih led so many of our ancestors to feast when they had the opportunity,
and, as long as it tasted good, not to worry about its nutritional properties. These
forces, whih we have suggested above are in part 'hard-wired', have not only driven
