There are studies that have shown that people who consume diet sodas increase weight, for example here in the elderly. There are several such studies http://www.theheart.org/article/1245493.do Why should this be. There are also rodent studies that suggest the mechanism by which this happens. http://www.ncbi.nlm.nih.gov/pmc/article ... 373389.pdf Researchers have also discovered sweet taste receptors in the gastrointestinal tract. There are those that consider these have an important role in the control of food intake and this is disrupted by non calorific sweeteners. SO far there are only a few human studies and the results are inconsistent http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3319034/ it is something being actively investigated at the moment. eg: http://clinicaltrials.gov/ct2/show/NCT01200940 When I was first diagnosed 8 years ago, I did try to substitute sugar in desserts and on fruits with sweetener. Somewhere along the line I realised it wasn't necessary or good for me and stopped. I now never have to add sweetener to things like berries (well maybe gooseberries) . If I eat anything sweet it needs to be very subtle as in very dark chocolate or the occasional 'cake' like macaroons made with almonds and a small amount of sugar. Anything too sweet now tastes quite horrible.