A blood glucose level <3mmol with a thumb prick test.
It's easier to measure ketones with ketone prick test.
GKI is more accurate way of looking at the body's ability to use ketones as energy.
If you’re on the keto diet, you know all about ketones, an alternative fuel source for the body when glucose is in short supply, but are you aware of the Glucose Ketone Index (GKI)? Because stress, fasting or a high-fat
foracare.com
When starting keto, both levels are all over the place. It takes a while before the body adjusts to its own normal levels when it gets efficient in fat burning.
Different people are on different ketone levels even when on the same diet. Some have naturally higher glucose levels, some have higher ketone levels.
Pee sticks are a reasonable guide but not definitive as can test negative while you are in keto due to all the available ketones being used for energy and none excreted .
Actually this is incorrect. Pee sticks are very unreliable way of measuring ketones and they only measure AcAc. Blood test can measure BHB and is more accurate.
When starting keto, the pee sticks show high results because body is inefficient in using ketones, but later on will adjust to show little or no ketones. It's better to go with blood tests for consistent results.
Over eating protein will push the body out of keto as excess protein is converted into sugar via glucogensis and used/ stored as the body will always go for the most easy available energy source ie sugar.
Gluconeogenesis is a demand driven process and also very metabolically taxing process. It's very slow and only initiated when glucose is needed by the body. Rest of the protein is either broken down to aminos and/or evacuated. High protein intake in keto is very unlikely to kick anyone out of ketosis. Fat also increases insulin levels, basically eating any macro will do that to a varying levels.
Glucose adapted have higher demand driven process, hence higher insulin levels when eating high protein, but that will drop with the fat adaption.
High protein foods also take more energy (25%) just to process it.
Glycogen depletion from from liver and muscle mass will vary between people based activity, type of activity and muscle mass. 24hrs or less is possible if you start fasting after a low carb diet and use anaerobic exercise to deplete or/and use glucose disposal agents or carbless insulin injections. Average person coming from a normal carb based diet will be 72 hours ish.
Also depends on metabolic flexibility. Metabolically flexible people burn whatever source is quickest to access. People on high carb diets tend to utilise carbs better and fats worse, where as fully fat adapted people tend to have higher threshold for glucose burning basically meaning that in aerobic zone (which is wider with adapted people) they will use much more of the fat available in the body preserving glucose more for more demanding anaerobic activities. Some people who've been on keto a long time actually can have a very poor utilisation of carb/glucose due to fat adaptation.