You’re heading to the supermarket and you are hungry. Although you’re trying to stick to your list, you’re still grabbing items that you didn’t plan to buy – and secretly you have the intention of consuming them all that night. A litre of yoghurt, an entire block of chocolate, packets of your favourite biscuits, ice cream, lollies, and six hot cross buns*. You might gobble this food and feel slightly overstuffed later on. Instant gratification in a millenial generation? Perhaps not! Research indicates that this type of behaviour isn’t restricted to the supermarket or modern society – it also occurs in humans that live in hunter-gatherer camps.
A study published in Evolution and Human Behaviour by Berbesque et al. (2016) documented eating habits of the Hadza hunter-gatherer men. The Hadza are a traditional hunter-gatherer group who live in Tanzania. The group is comprised of approximately 1000 people, within which 250 individuals travel out and forage for food. Hazda men typically forage for animals, honey, and sometimes fruit. The task for women and children at camp is to dig for tubers (similar to potatoes).
Studies of food sharing in hunter-gatherer camps up until now have given the impression that when groups go out, all the food acquired is brought back to the camp and shared among the others (Marshall, 1976). This is actually due to logistical problems faced by researchers studying hunter-gatherer camps. Researchers have been unable to divide their time trying to study the behaviour of individuals at the camp and also those that forage for food. Research has therefore only focussed on those individuals in camp. Therefore studies of the behaviour of foragers are uncommon.
In the 2016 work, researchers followed the Hadza men as they went on a walkabout. Their behaviours, especially their eating habits, were recorded from the time they left the camp in the morning. The researchers followed a total of 146 people over 12 years from 2001 to 2013. They visually estimated the amount of food the Hadza men consumed (e.g. three handfuls of berries, golf-ball sized bites of honey) and then calculated the amount of kilocalories in the food consumed.
What Berbesque et al. (2016) found was that the Hadza men consumed a substantial amount of food while foraging away from the camp. They weren’t just snacking on food to give themselves a little energy while foraging, they consumed 90% (2405 kilocalories) of their average daily total energy expenditure. This meant that when they returned to camp without any food, it was because they didn’t forage a surplus amount of food to share.
This research has shared some light on the eating habits of hunter-gatherers and past human forager societies and their evolution. It may be the case that in those societies all the food foraged wasn’t shared amongst everyone after all.
So when you start to snack on the high-calorie food you just bought at the supermarket on the way home, remember that you are not alone and you aren’t doing anything wrong, in fact it may be a part of human nature.
* Is Zach speaking from personal experience? Answers to firstname.lastname@example.org.
Berbesque, J. Colette, et al. “Eat first, share later: Hadza Hunter-gatherer men consume more while foraging than in central places.” Evolution and Human Behavior (2016).
Marshall, Lorna. The! Kung of Nyae Nyae. Harvard University Press, 1976.