Just want to say everyone, that after a long silence on the Palaeolithic Diet symposium, what a great discussion this is. Have decided that I am going to reply to lots of points raised by different people in two emails, separated by subject, as otherwise we are getting longer and longer messages with things copied in. I shall reply to Ed Thompson's more specific email re his and my views in another, so everyone can skip that if too bored or not enough time! So, this posting concerns obesity. Ed Thompson suggests that I think the current increase in obesity is due to lack of willpower, whereas he has his suspicions of the conspiring food industry. In a way I do think it related to willpower, but totally unavoidable as it is an age old drive to eat more, as I go with the 'thrify gene' theory that humans throughout all evolution have struggled against starvation, and therefore we have been genetically selected to be on the plump side - gain weight easily in times of plenty, so there is a reserve in times of hardship. For a great, if v personal view of recent selection pressures such as documented famines, see: Prentice, A. M. (2001). Fires of life: the struggles of an ancient metabolism. Nutrition Bulletin 26: 13-27. A thought-provoking read. I don't think we can blame the food industry, because all they are doing is capitalising on a natural urge. We are programmed to prefer energy dense foods, and this programming came about long before the food industry happened. Look at the goddess figurines from Neolithic Catal Huyuk in Turkey (6000BC) - they are hugely fat. Fat has been recognised and worshipped as desirable for a long time in human culture and society, until very recently when all of a sudden there was no shortage of foods to balance out our desire to eat. This desire for energy-dense foods is also why people will never be able to eat as much as they like and be as thin as they like, despite what Bob Avery says. Because what he overlooked in his comment that we would be fine if we all ate only raw veggies, is that when people want to eat as much as they like, they want to eat as much as they like OF FOODS THAT THEY LIKE. I would venture that most people would think that eating only raw veggies isn't that much more palatable than cutting back. Thinking about human weight and whether we are the only species that struggle. Barry Groves says that 'all animals in their natural habitat are a normal weight.' That point is one that most animal researchers would debate. Some can often be severely underweight. The mechanism for controlling animal weight in the natural habitat is not simply natural satiety, although that will play a part. There can be an oscillation in weight of an individual, as Andrew Millard pointed out in the case of an overweight lion that cannot catch its food, so starves until it is thin enough to be fast enough to catch it. Or there can be changes in the population size and structure resulting in the most number of (just) reproducing individuals, who are not necessarily in prime individual health. The latter point has been amply demonstrated in the red deer on Rum: Tim Clutton-Brock et al.'s work that a season of plenty leads to fatter deer in the very short term but then greater reproductive success which will use up all the reserves. A similar thing has been observed in feral donkeys in Australia, where after culling of a population to provide more grazing per individual and improve individual fitness, the population rebounded in size very quickly, growing at 20% a year, and with far greater survival of neonates, to get back to the original density. Both studies are detailed in a v good book: White, T. R. C. (1993). The inadequate environment. Nitrogen and the abundance of animals. Berlin, Springer Verlag. On the flip-side, we are not the only animals that will be obese if given the chance. Robert Sapolsky's famous study of a olive baboon troop in the Masai Mara, whom he wrote about as 'junk food monkeys', completely abandoned their usual diet when they discovered that they could feast to their hearts' content on garbage from the national park buildings. Despite that they matured earlier and had a wonderful time with endlessly available food, they also became obese, cholesterol (LDL) rose, and they all finally got a nasty dose of bovine TB. I know that one can hold up hands in horror and say humans were responsible for the waste, but the baboons CHOSE to eat this food, because it was an easy life. We humans do much the same. Next mail: carnivore or omnivore?? ----------------------------------- Dr Tamsin O'Connell Research Laboratory for Archaeology University of Oxford 6 Keble Road, Oxford, OX1 3QJ, UK tel:01865-283641 fax:01865-273932 [log in to unmask] -----------------------------------