| > Even when practicing a very low carb diet your liver is "topped up" through gluconeogenesis while you are sleeping. Not really, gluconeogenesis is a pretty inefficient pathway, from my reading on the subject you can't make more than 200 calories of glucose per day via gluconeogenesis, which is pretty low and definitely not enough to replenish the glycogen stores, only enough to keep them from being completely depleted. I'm struggling to find the reference.
But you can also ask most doctors — if you give urine or blood in the morning, nobody raises an eyebrow when seeing ketone readings because it's a known effect. Also note that I'm not saying that all glycogen is depleted. Glycogen stores are never depleted, as the glucose sparing effect eventually kicks in (aka physiological insulin resistance) and yes, some of it is replenished via gluconeogenesis. --- > by ketosis you mean the body is producing enough ketones to power itself No, ketosis is a metabolic state in which the liver is producing ketones in response to a short supply of glucose, with significant ketones being detectable in the blood or urine. That's it. And availability of ketones in the blood stream is enough for them to be used. There is a threshold of 0.5 mmol/L of ketones that people in the keto community use, but it's completely arbitrary — nobody knows why that threshold isn't 0.3 mmol/L. Regardless, I'm at 0.5 mmol/L in the morning while eating between 150 and 200 grams of carbs per day. --- > "You don't need to starve yourself, you just need to put your body in a scenario where the energy demands overtake the available energy in the form of blood glucose (and strain the stores in the muscle and liver)." We agree here — yes, once the glycogen stores are depleted enough, the liver starts producing ketones and of course exercise can do the trick. There is one caveat ... during exercise ketone usage also goes up, and exercise also drives your blood sugar up, so if you measure the ketones immediately after exercise, the readings can be misleading. But yes, active people can burn through their glycogen stores really fast. |