According to Daniel Lieberman, Chair of the Department of Human Evolutionary Biology at Harvard, over the course of millions of years, apes living in the forests of Africa changed to modern humans. We humans were hunter-gatherers, moved frequently, lived at very low population densities, and usually walked 10-15 miles every day searching for food and water.
Lieberman explained epidemics didn’t exist prior to the emergence of agriculture. The population density of hunter-gatherers was less than one person per square kilometre, which is below the threshold necessary for fatal or deadly diseases to spread. The industrial revolution immensely altered the way we work, interact and eat, as well as allowed for rapid population growth at far greater densities, which is why the majority of people these days have better health and higher standards of living than ever before.
Changes in culture come at a cost. Most essential inventions of the twentieth century were labour-saving machines, aero planes, elevators, vacuum cleaners, dishwashers to name a few. They made life pleasant and convenient. In the past, humans walked many miles every day. Eating meant hunting, collecting as well as growing, but the picture today is different. Today, most people eat food that are processed and produced thousands of miles away. All of which is no doubt problematic from the perspective of evolution. The outcomes are not surprising. The last few years have seen an explosion of diet and lifestyle diseases, such as Type 2 diabetes, heart diseases, hypertension, obesity, high blood pressure, arteriosclerosis, COPB, cirrhosis, nephritis and much more.
The pervasiveness of diabetes has tripled over the last two decades and now costs our health system $5 billion per year which is around ` 500 crore approximately. Four times as many adolescents are overweight today as were in the 1960s and the number is expected to increase steadily in the coming decades. In accordance with a report given by the International Diabetes Federation in 2012, India’s diabetes numbers are expected to cross the 100 million mark by 2030. Life expectancy has grown by an impressive number. We are living longer, yes, but not always living healthier. The question then becomes, does a longer life invariably mean more chronic diseases vis-à-vis lifestyle diseases?
So far we have been moving in an absolutely wrong direction. It is roughly estimated that since 1970, the consumption of added fat has dramatically increased by about 60%. Our food environment affects how we eat and our built environment (the streets, buildings, open spaces etc.) affects how we move. Research shows a number of neighbourhood features can increase physical activity and promote healthier eating habits for residents living in those communities, such as having more places safely accessible by foot and greater access to community gardens or parks.
The Bottom line
Increasing the ability of kids to walk to school, expanding access to safe outdoor places, and restricting the access to fast food corners or restaurants may be useful to combat youth obesity and other lifestyle diseases. Kids living closer to open gardens or parks have higher levels of physical activity. We must understand that we do not just pass on genes; we are passing on environments too. The greatest advances in twentieth century life expectancy came from environmental changes as well as public health; mostly outside the walls of hospitals or nursing homes, and sometimes outside the domain of medicine altogether. The greatest steps in reducing diseases in the twenty first century – allowing kids, adults and elderly to live longer and better will require the same.