According to some people, taking apple cider vinegar helps to burn fat. Here's a salad dressing that is easy to make and gets you a daily dose of apple cider vinegar.
3 Tbsp apple cider vinegar
3 Tbsp olive oil
salt, pepper to taste
This has zero carbs, and olive oil is of course very healthy for you. Heck, vinegar is healthy for you, too, and eating fresh greens is healthy for you. So no matter how you look at this, you should have a salad with each meal and you might as well have olive oil and apple cider vinegar on top of it to help it go down.
Note that despite people claiming that apple cider vinegar "has potassium", it only has 11mg per tablespoon. The US RDA for potassium is 3g for women and 6g for men. 3g is 3,000mg. Even if you have 3 tablespoons of apple cider vinegar, you are only getting 33mg total - not even 1/100th of the potassium you need EVERY DAY. So this is NOT having an important effect on your potassium levels.
Also note that vinegars are sensitive to light. Make sure you keep your vinegar somewhere dark, so that you don't spoil the effect it DOES have on your health.
Lisa Shea's Library of Low Carb Books