I wonder if we can actually digest and absorb calories from xanthan/ guar gum and glucomannan. Nutrition labels claims that they have around 200-300kcal per 100g but they consists mostly of fibre. Do we digest and absorb this calories then?
I’m assuming is soluble fiber if it’s listed as 200-300 cals. If it wasn’t fiber it would be 400 cals. Soluble fiber is ~2 cals per g, and when multiplied by 100 gives you 200 cals. So yes, we would absorb the calories.
Our body cannot break down soluble fibers. Bacteria in our colon do this for us. But they leave behind some nutrients we will still absorb and hence get some kcals from it.
Depending on the bacteria some or all soluble fiber will be digested. Insoluble fiber will not be digested.
Glucomannan is used to lose weight so i do not think you get a considerable amount of calories from it. Same goes for guar gum which in a hydrolysed form it is used as a very good prebiotic. It may give out some calories but nothing considerable to fuss about.