A guy like Michael Phelps would eat 20,000 calories a day when in training - mostly from carbs (sugar), but I don't think he ever had to worry about diabetes. In his case, sugar gave him the energy he needed to perform physically. Too much sugar is subjective, but sugar shouldn't be labeled as toxic.
Sorry but your example is wrong... Yes Michael Phelps did live on a 12,000 calorie a day diet, while at his peak, which was indeed high in carbohydrates, but not nearly as high in sugar as you are trying to claim, and Michael Phelps was doing this when he was 23 years old, when the bodies ability to repair damage done by toxins and other things are still strong.
Ever seen a 23 year old a night after a bender vs a 40 year old? Even if they are the same in terms of consumption, weight and every other measure, odds are overwhelming the 23 year old is going to shake it off far faster than the 40 year old.
Toxins are toxins, they are toxic, they do damage to your body, just because you are younger and able to deal with and repair that damage better than an older individual does not mean that they are not toxic or do no damage.
Refined sugars are toxins, period. They are toxic to your body, on a whole range of levels, your body doesn’t have a inflammatory response within your arteries and veins after you consume something high in refined and processed sugars because your body is happy... its NOT. its a TOXIN and your body is reacting to it.
No, you aren’t going to die today from eating a candy bar, but don’t kid yourself that ongoing consumption of high amounts of refined and processed sugars do not have an impact on your body. Its the SINGLE GREATEST INDICATOR FOR HEART DISEASE, period. Its not saturated fats, or salt, or any of the other things they try to blame it on.. the single worst thing you can do for your cardiovascular heart is consume large amounts of refined sugars, period.