Diluting a small amount of apple cider vinegar in 8 ounces of water won't break your fast. In fact, it might actually be a really good idea. According to a study published in the Journal of Medicinal Food in 2018, apple cider vinegar can lead to positive metabolic changes that help promote weight loss. Drinking apple cider vinegar every day may also reduce total cholesterol, triglycerides and LDL or "bad cholesterol" levels.
Two ground-breaking studies have recently been published on the effects of intermittent fasting on males. One group of researchers studied the effects that 16 hours of intermittent fasting had on males that lift weights. They found that muscle mass stayed the same, fat mass decreased significantly, and the males who fasted for 16 hours a day burned more fat for fuel compared to the control group that only fasted for 12 hours.
Yes — you read that correctly — 24 hours of intermittent fasting without any resistance training and these subjects were able to preserve more muscle mass than the subjects that ate fewer calories every day without fasting at all. This finding contradicts our common sense, but when we dig deeper into autophagy we can find the mechanism behind this result.
When you eat a meal, your body spends a few hours processing that food, burning what it can from what you just consumed. Because it has all of this readily-available, easy to burn energy (thanks to the food you ate), your body will choose to use that as energy rather than the fat you have stored. This is especially true if you just consumed carbohydrates/sugar, as your body prefers to burn sugar as energy before any other source.