Nutritional interventions are under used because it’s difficult for people.
Not for lack of physicians and others preaching about it. Most people are quite aware that they need to cut down their caloric intake, sugar, and so forth.
But most don’t.
One of the major reasons is most people lead a sedentary lifestyle due to current and past technology, and developing technology.
140 years ago, in the 1800s, most people led much more physically active lifestyles. As society has progressed technologically, we have become more sedentary due to the change of the nature of our work, transportation, and a host of other factors such as technological toys. Kids don’t run out and play as much as they used to. You get the picture, you already know all this.
The difference is as we became more sedentary, medical technology improved, and with the development of antibiotics and other medicines, things that we used to die of early, we don’t die of anymore. Diabetes is treatable. Hardly anyone dies of infections anymore. So on and so forth.
So we lead longer lives but with more sedentary lifestyles. If we led the type of active lifestyles people led in the 1800s, but with current medical technologies available, most people would probably live to over 100. Although that may not be a great thing from a socioeconomic/medical standpoint.
People get way more expensive the more they age in terms of medical costs.