When your body goes into ketosis, it will start to produce by-products called ketones. This includes acetone—yes, the same chemical found in nail polish remover, which your body actually naturally makes on its own, according to a 2015 review of research. Because acetone is a smaller molecule, it tends to make its way into your lungs. You’ll eventually exhale them out, resulting in “keto breath.” Your mouth might also have a metallic taste, but it won’t last forever as you adjust to the diet. Just be diligent about brushing your teeth!
“Net carbs” and “impact carbs” are familiar phrases in ketogenic diets as well as diabetic diets. They are unregulated interchangeable terms invented by food manufacturers as a marketing strategy, appearing on some food labels to claim that the product contains less “usable” carbohydrate than is listed.  Net carbs or impact carbs are the amount of carbohydrate that are directly absorbed by the body and contribute calories. They are calculated by subtracting the amount of indigestible carbohydrates from the total carbohydrate amount. Indigestible (unabsorbed) carbohydrates include insoluble fibers from whole grains, fruits, and vegetables; and sugar alcohols, such as mannitol, sorbitol, and xylitol commonly used in sugar-free diabetic food products. However, these calculations are not an exact or reliable science because the effect of sugar alcohols on absorption and blood sugar can vary. Some sugar alcohols may still contribute calories and raise blood sugar. The total calorie level also does not change despite the amount of net carbs, which is an important factor with weight loss. There is debate even within the ketogenic diet community about the value of using net carbs.
It is no secret that Southern Europeans who eat a more Mediterranean Diet, consisting of vegetables, fruits, lots of fish and plenty of olive oil, have a higher life expectancy with fewer diseases. An average, Italians and Spaniards consume about 13 liters of olive oil per person per year. While the entire diet does play a big role in how healthy people are, it seems the use of extra virgin olive oil is the major contributing factor to longevity and health.
And monounsaturated fat isn't the only thing olive oil has going for it nutritionally. Some olive oils come with phytonutrients that may offer their own disease protection benefits (still, it's not clear whether most of us can take in enough of these phytonutrients without going overboard on olive oil, says Joyce Nettleton, DSc, RD, researcher and editor of the PUFA Newsletter).