I don’t know if your answer is good for yogurt. Yogurt is obtained by fermentation of milk. There are three changes in the fermentation process. First, a part of lactose becomes lactic acid. Second, a large amount of lactic acid bacteria is produced. Third, some proteins are hydrolyzed and some vitamins are produced.
If you only experienced yogurt with such a fermentation process, the nutritional value is not reduced, and there is some increase.
However, such original yogurt is rarely eaten. Most of the yogurt in the supermarket is filled with a lot of sugar. Considering the adverse effects of sugar on the health of modern people, the nutritional value of these delicious yogurt in the supermarket is not as good as pure milk high.