Study Investigates Dairy Calcium-Weight Loss Link
This was a fairly simple human study that compared the effects of high and low dairy calcium diets on the (fecal) excretion of fat, total energy (i.e., calories) and bile acids. Bile acids are metabolites of bile, which is produced by the liver, stored in the gallbladder, and released into the digestive tract to help digest and absorb fats from food. So bile acid excretion relative to calcium intake was studied since calcium can and does bind to bile acids; this was one possible mechanisms behind the calcium-obesity link.
The study showed that a high-calcium diet nearly doubled the level of fat excretion but did so without effecting bile acid excretion. So it’s probably not due to calcium-bile acid binding. Whatever the mechanisms are, since a great many people need more calcium than they can obtain from their diet, calcium supplements may have implications for obesity as well as high cholesterol, although more studies would be needed to validate any benefits. In the meanthime, It may be wise to take your calcium supplements 6-8 hours apart from oil-based supplements like fish oil and CoQ 10.