No ... over the last hundred years, with improvements in public hygiene, water supplies, and vaccines, we have essentially conquered lethal childhood disease. We have effectively conquered food-borne illness. We have found effective anaesthetics and antibiotics and discovered effective methods of surgery so that essentially no one dies of minor trauma. The same techniques mean that most birth defects are now survivable.
Heart attack, cancer, etc haven't skyrocketed as causes of death because of our diet ... they've skyrocketed because we now live long enough for these to be the primary things that take us out, because we've beat all the other stuff! All these diseases have (obviously) existed for millions of years, but essentially no one ever succumbed to them because they didn't live long enough!
Can most of us eat better and exercise more and eek out a few more years? Sure. But I'd much rather our situation today than that of our forbears of even a hundred years ago.