I don't think it interferes with my weight loss, but I sure feel a lot healthier and more energetic when I don't eat or drink anything with aspartame. I also think it is addictive. A few months ago I noticed that I had gone from occasionally having aspartame, to drinking one diet Coke every day to drinking several diet Cokes every day and I just felt lousy. I went cold turkey and stopped the aspartame. It took me about three weeks to get over the cravings, but I am glad I did it. I just feel healthier without it.