The Longest-Running Evolution Experiment

(Speculation ahead!) Interesting point in video posted recently by Veritasium: Basically, they are doing experiments to track evolution in "realtime" of some organisms. During the conversation the guy mentions that the population growth of their organisms are controlled by adding or removing glucose for them to consume - basically as long as glucose is available, there will be growth. (First 5 minutes of video) This is really not my field at all, but I found it interesting that sugar has that great an effect on growth. Considering how much sugar most humans eat, considering the gross amount of other organisms in our bodies.. there must be some kind of measurable effect on our microbiome by eating more sugars (or things that use glucose). What if sugar is ~the~ culprit for many diseases (cancer anyone?)? I'm not anti-sugar, just speculating. Criticism welcome, am I on the right path to think this way? [this video]

There are two factors now which make things different: 1. As other commenters have pointed out, the ease of spread of any disease is orders of magnitude higher now than it was during cave-man days. With crowded cities, public transit, and air travel, pandemic-level diseases can spread across the world in a matter of days or weeks. 2. Much more importantly, our use of medicines (antibiotics, antivirals, antifungals, etc.) have put extreme selective pressure on pathogens to evolve to become resistant to them. We are, in a sense, selectively breeding pathogens that are both good at infecting humans and resistant to our treatments. That is a focused selective pressure that has never existed before, and may pose the biggest threat to us in the next 50-100 years. For a concrete example, look at this experiment which shows how quickly bacteria can evolve to overcome levels of antibiotics that are orders of magnitude more than we would ever give a human [0]. Yes, there will generally always be some subset of the human population that is resistant to any particular disease, but our measure of success is not "5% of humans will survive the next pandemic, so we're all good, let's it move along nothing to see here." If we start to regularly have drug-resistant pathogens that make hospital stays very dangerous for patients (imagine having a 1/3 or even 1/10 chance of dying at a hospital due to an infection entirely irrelevant to your condition) or just more common COVID-level pandemics, th