They cause fermentation in the gut too.
this is toxic to the body in a number of ways. if your intestines are toxic, your bloodstream and thus whole body is toxic. most colds/flus are not the result of contact with germs, but people's whose bodies have become so toxic from poor diet, lack of sunlight, resulting immuno defenses are preoccupied with invasions via the skin, mouth, eyes, etc, and when you add a toxic colon on top of that, its like a huge breach in the wall of the fortress.
you also cant really digest really sweet things and complex carbs at the same time. complex carbs require a lot of digestion in the stomach, while simple sugars pass right on through the stomach and are processed in the upper regions of the small intestine. the end result is either fermented sugars passing through the whole gut, incompletely digested (and thus putrid/decaying) chunks of complex carbs passing through the gut, or both. this results in accumulated toxicity throughout the entire body.
THEN think of the chemical processing required to produce these refined sugars or starches or partial grain flours, etc. SUGAR ISNT WHITE! its bleached. do you really think 100% of all the chemical agents required to bleach a refined carb is removed during processing? the FDA allows a certain amount of toxic chemical waste in your food for this reason: its impossible to remove it 100%. then consider the irradiation processes many/all of these foods go through - exposed to radiation to preserve its shelf life! all of the phytonutrients (those actually remaining from the other chemical processing) are completely annihilated, and some of the "vitamins and minerals" are "refortified" in order to give your food an inkling of nutrition. these refortified chemicals are vitamins produced in some dusty grimey factory in central asia or who knows. in every packet of pure white sugar, youre going to have a certain percentage of toxic chemical waste, radiation, preservatives, etc, which all have a heavy impact on health in even small doses. think of what is happening to your cells if this is what theyre fed every single day.
wouldnt u just rather get your vitamins, minerals, nutrients, etc, from some cellular activity that has 1 billion years of evolutionary engineering behind it? why strip it all out on some factory conveyor belt?
refined carbs also do things like kill intestinal cilia, cling to intestinal cilia and reduce absorption rates of nutrition, and cause the cellular consumption and production of energy to become "confused." certain faux-sugars, or improper levels of various sugars at the same time, or even artificial sugars, send the wrong chemical signals to the brain which in turn causes improper conversion of food into fats, especially fat on certain organs, and cause improper levels of insulin in the blood.
the effects are pretty complex, from something as simple as a sugar molecule hitting the tounge. if you trick the brain into thinking its getting (just making up some silly variables here) 0x99AHcQ and instead it gets 0x99AHckJ, the overall machine has some confused effects down to the quantum level.
nature never made a honey smoked ham sandwich. nature also never made any high fructose corn syrup. ever seen any refined white flower pancakes with corn syrup based "maple" syrup out there growing in a bush? thats cuz they dont exist, silly humans naive to their bodies invented those things. the problem is, you have hundreds of thousands of years evolving with a diet that doesnt include these refined carbohydrates, and in just 60 years, were seeing how bad they really are for our digestive system.