Advancing medical technology has brought tremendous and accelerating benefits to health and longevity over the past century. The staggering increases in wealth that support this advance introduce more subtle forms of risk to health and wellbeing, however - disease and ill health that is more a matter of what we do to ourselves than what is done to us by various pathogens. Type 2 diabetes, for example, is a lifestyle condition that is essentially caused by eating too much over a long enough period of time. Adopt the right lifestyle and you are very unlikely to suffer its effects. Yet so very many people have type 2 diabetes - and as the population of various regions of the world move from being poor to being wealthy, they suffer ever more from these sorts of medical conditions, even as their lifespans increase.
It is clearly the case that failing to be more successful and wealthy than your ancestors is worse than having the opportunity to eat yourself into an expensive and debilitating degenerative condition - but why sabotage the benefits that you do have? Most of us should know better, but the siren call of low-cost calories and luxurious laziness is very effective. Still, it is a choice. We have willpower and the free will with which to use it. You can blame your genes and circumstances if you like, but that's just as much a choice as it is to surmount those challenges to stay lean and healthy.
Here's a readable open access paper that covers some of the high points on this topic:
Most of the human population in the western world has access to unlimited calories and leads an increasingly sedentary lifestyle.
Ancient man was a hunter-gatherer, often travelling long distances to find food, avoid threats and seek shelter. In contrast many modern western societies have transformed their surroundings in order to minimise (or even eliminate) environmental threats and stresses that our ancestors were exposed to, including food and water shortages, predation, infections, extremes of temperature and the need to carry out regular physical activity. Moreover, the modern western environment now contains almost unlimited supplies of foods containing high level of saturated fats, salt and refined sugars. This also appears to be coupled with a reduction in the consumption of plant products including fruits, nuts and vegetables. The result of this obesogenic environment is a burgeoning rise in lifestyle-induced diseases that are generally associated with energy imbalance, abnormal fat deposition and inflammation. The links between obesity, the metabolic syndrome, diabetes, vascular disease and even cancer, and a sedentary lifestyle, are now all too clear.
In this regard, our ability to succeed has outstripped our ability to manage the consequences of our success - a common theme in the history of human development. Success is far better than failure, of course, but success while sidestepping any potential downsides is even better yet. This is perfectly possible for most of us as individuals: we can enjoy the benefits of this technologically advanced society we find ourselves in, so far removed from our near ancestors that it's hard to even visualize the level of pain and privation they suffered on a constant basis. We just have to choose to devote willpower and time to a sane diet and moderate exercise. It's that simple.