Does adding thickener to foods reduce nutritional value?

Some thickening agents like flour and cornstarch can reduce the nutritional value of some foods. Other thickening agents, like xanthan gum or guar gum, may not have this effect.

When you're cooking and come across a recipe that requires some sort of thickener, such as cornstarch or flour, do you stop to think about the nutritional value of those ingredients? 

While it's true that these substances can change the consistency of a dish, they also provide calories and nutrients. 

For example, one cup of potato soup made with regular potatoes provides around 135 calories and 4 grams of fat.

Adding a thickener to a food can mask the true taste of the food, but does it negatively affect nutritional values? Thickeners are made from substances other than grains or starches. Some thickening agents are made from soy, other plant sources, sweeteners like sugar to thicken jams and preserves, or other things like arrowroot. The question is not about how healthy the food is because that depends on what you eat with the whatever you’re cooking.

Foods such as yogurt and rice dishes often have added thickeners such as corn starch to make them thicker. However, it is unclear if these additives provide any nutritional value or reduce nutritional value. One study found that thickener (guar gum) increased the thickness of the food by up to 10 times, but this meant that there was less soluble fiber and other nutrients present. This research shows that because of this increased thickness, the energy intake may also increase.