I know exactly what you mean! And it has nothing to do with flab or muscle tone. No crunches could deal with this. It just appears some days. One day my tummy will be fairly flat. And the next day, I look pregnant. It is better now on Atkins, but still happens frequently enough to be annoying.

I think it may be an intestinal yeast overgrowth (Candida). I had some cream cheese yesterday, and I am so bloated today. I notice that cheese and dairy are the worst, but I never thought about the vinegar in the salad dressing! Vinegar encourages intestinal yeast overgrowth, too. I take caprylic acid and pau d'arco supplements to help with the candida. I guess the vinegar and cheese will have to go. I know I really need to do the candida diet, but the cheese is SO wonderful as a treat. I don't know if I can take it on meat and veggies alone!

Anyway, try cutting out the offending foods and see if it helps. You can get caprylic acid and pau d'arco at almost any health food store.

Good luck!