clean eating is the best way to combat it, if you already eat alot of fruit & veggies then it definitely could be water retention.... veggies definitely give me water retention. Coconut water also helps with water retention its like a miracle in a can, i thought I was getting a fat tummy and then i started drinking coco water and I went back to flat!

Exercise could help, I like pilates for tummy its a serious workout! you can find vids on youtube