I am losing weight and don't know why

I am feeling fine and I still eat, however, over the past three or four months I have lost at least 30 pounds. Don't get me wrong, I'm very thankful because I need to lose the weight. My husband says he thinks it is because we aren't eating out as much and that I'm cooking healthier. That could be the case. I'm also drinking lots more water and sugar free kool-aid because I am a diabetic. Just thought I would throw this out and see if anyone has any other ideas of what could be causing this. Thanks and have a great day!!