How sugar and sugar alcohol affect one's (bone) health

-FIXED.

There is no direct link between sugar consumption and negative impact on bones. However, consuming excessive amount of sugar and not getting adequate nutrients can affect bones.

You should study the topic so you know what your nutritionist is talking about and so you can make decisions about what to eat when the need arises.

The only nutritionist I have studied is Adele Davis. She says your concern about sugar is not as important as what you plan to do with good health in case you happen to acquire it.

She also offers the term "part-smart". The human body needs about forty nutrients, some in balanced amounts, to maintain health. It is good to be concerned about nutrition, but if you are only concerned about one nutrient you are approximately one fortieth part-smart.

These books are old, 1960s era, but they are still the most popular introduction to the field. https://www.amazon.com/s?k=adelle+davis&i=stripbooks&ref=nb_sb_noss_1

Both are bad for you. Too much sugar can cause all sorts of health problems and alcohol can not only make you drunk but fat as well.

I am talking about sugar alcohol, a sugar substitute, not alcohol. What does alcohol have to do with sugar alcohol?

https://foodinsight.org/sugar-alcohols-fact-sheet/

An alcohol is any chemical with -OH at the end of the molecule. The name therefore has -ol at the end. It might or might not resemble booze in some way, but usually not.

Sugar has dofamin - the hormone of joy. When you are depressed you need dofamine and you feel better. That's why you get used to sugar. When you for a while not eating it you became depressed and you need time to overcome it, because you brain can produce this hormone itself. And the dose is smaller. When you eat suger you get addicted to bigger doses of this hormone and can't feel emotions as they really are, they bring you less dofamine as sugar.

If to speak about not mental health - sugar is the nutrient basis for all kinds of patological bacterias that live inside us. We have friendly and nonfriendly bacteria and they synthesing vitamings etc. It's a mistake to think that the vitamines come out of food. We feed bacteria and they provide us all the elements. If we feed them the food they eat than its alright, but when we eat sugar etc. we provide with food the unfriendly bacteria and they destroy us.

Perhaps you mean dopamine? That’s a starting point as the rest of your post is nonsense as well.

High intake of sugar can negatively impact bones because it increases inflammation, raises blood sugar, and may lead to calcium loss through urine. Over time, this can weaken bone density and raise the risk of osteoporosis. Excess sugar also displaces nutrient-rich foods needed for bone strength, like calcium, vitamin D, and magnesium.

Sugar alcohols such as xylitol, erythritol, sorbitol don’t cause the same calcium loss or spikes in blood sugar. They are generally neutral for bone health, and some studies suggest xylitol may even help mineralize teeth and bones. However, excessive amounts can cause digestive discomfort.