Sugar substitutes interact with the same taste receptor, which is responsible for the perception of the taste of sugars, including sucrose, so sweeteners and sugar taste very similar to us. However, having the taste of sugars, sugar substitutes a) are not a significant source of energy and b) do not have a direct or indirect effect on blood glucose levels. The second property of sweeteners is very important and beneficial for diabetics, since their body does not cope well with regulating the amount of glucose in the blood, and the absorption of sugars. Also, sweeteners can be beneficial for those who need to lose weight. As for the harm of foods high in simple sugars, it comes not only from the sugar itself, but also from the fact that these foods often replace more useful sources of energy in our diet. Desserts are often just dummy foods that are high in calories and low in vitamins, essential amino acids, and trace elements. A similar product with a sweetener will not be much more useful for a healthy person. Nevertheless, excessive consumption of sugar leads to obesity and diabetes, therefore, if the content of sweets in the diet cannot be reduced in any other way, then it is better to switch to products sweetened with sweeteners.
Such substances should have two main qualities:
1) Be sweet, and it is desirable to taste as much as possible similar to the sugar we are used to. (And keep this taste under different conditions - when dissolved in hot water, acidic environment, etc.)
2) Do not have the "harmful" properties of sucrose, that is, be low in calories and not participate in carbohydrate metabolism. I am writing in quotes, because harm in this case is a relative concept.
Well, there is a third requirement, but it must be met for all food products, not only for sugar substitutes - this is safety. The substance should not be toxic, carcinogenic, etc.
Actually, all sugar substitutes have these properties to some extent.
It's very simple: sugar substitutes, such as aspartame, are simply many times (hundreds or thousands of times) sweeter than sugar, which makes it possible to add them in much smaller quantities to the same cola. That is why it is called dietary