Chasing blood Ketones instead of focusing on hormone signals: "The higher the number means you have more Ketones circulating in your bloodstream, but that does not mean that you are better at burning fat for fuel," Mavridis points out. "You must be in nutritional Ketosis, which is described as being between 1.5 - 3.0 mol/L on the blood Ketone meter. You will know once you are fat-adapted from hormonal signals, and not from higher Ketones on the blood meter," she adds.
Why higher fat and moderate protein? Fats have little to no effect on blood sugar and insulin levels. Protein does affect both blood sugar and insulin. If you eat too much protein for your ideal body weight or lean muscle mass (usually more than 1.5-2.0 grams/kg lean body mass), it can spark gluconeogenesis and raise blood sugar. Protein will also spike blood insulin levels temporarily, which can interfere with ketone body production. However, it is important to note that this is an individually driven parameter, as detailed in this excellent post from the Optimizing Nutrition blog.
Our bodies are incredibly adaptive to what you put into it – when you overload it with fats and take away carbohydrates, it will begin to burn ketones as the primary energy source. Optimal ketone levels offer many health, weight loss, physical and mental performance benefits.1There are scientifically-backed studies that show the advantage of a low-carb, ketogenic diet over a low-fat diet. One meta-analysis of low-carbohydrate diets showed a large advantage in weight loss. The New England Journal of Medicine study resulted in almost double the weight loss in a long-term study on ketone inducing diets.