Question

Why is it surprising that hunter-gatherers burn the same number of calories per day as a sedentary person in a western society?

Answer 1

Your Total Daily Energy Expenditure (TDEE) is an estimation of how many calories you burn per day when exercise is taken into account. It is calculated by first figuring out your Basal Metabolic Rate, then multiplying that value by an activity multiplier.

Since your BMR represents how many calories your body burns when at rest, it is necessary to adjust the numbers upwards to account for the calories you burn during the day. This is true even for those with sedentary life.  

Sice Hunter-gatherers maintain a traditional foraging lifestyle, hunting on foot using small axes and digging sticks, and without modern tools like vehicles or guns. Their diet includes no processed foods whatsoever.

Research is done in the following way --- To measure energy use, participating Hadza (Hunter-gatherer) adults wore GPS units to track how far they traveled each day. They also wore breath monitors while at rest and while walking to measure their metabolism in each state. And a measure of total energy expenditure was calculated from urine tests.

Those results are all the more surprising because the Hadza did appear to expend much more energy in physical activity, as they hunted and foraged. But activity differences did not translate into differences in total energy use. What’s more, even among members of the same society, Hadza people who walked a long way each day did not have measurably higher total expenditure than individuals who did not walk so much. It seems that people’s metabolisms may compensate somewhat for the activity level.

Lifestyle was not shown to be a contributing factor to one's total daily energy expenditure. In fact, total energy expenditure is remarkably consistent across global cultures and economies, and is perhaps "more a product of our common genetic inheritance than our diverse lifestyles." So whether you are hunting down and killing your dinner yourself or grabbing take-out after sitting in front of a computer all day, the calorie intake needed to supplement your energy expenditure is more or less the same.

Energy expenditure is the amount of energy that a person needs to carry out physical functions such as breathing, circulating blood, digesting food, or exercising. Energy is measured in calories, and your total daily energy expenditure (TDEE) is the number of calories you burn each day. To prevent weight gain, energy intake must be balanced with energy expenditure. So basically means that for a physiological activity like respiration, circulation, etc consumes most of the energy. As we share the same physiology regardless of where we belong, what we do, we have more or less same calories expenditure. It remains within our body configuration.