The liver: The hub of metabolism, not simply a “toxin filter” (provided the animal has eaten grass). Ideally consumed three times a week.
Eggs and butter: Excellent sources of good fats.
Fatty meats: You should avoid lean meats and reintroduce natural animal fat (tallow, clarified butter/ghee).
Plant flexibility
Plants are not essential, but they can bring pleasure. They should be chosen wisely:
Favor low-carbohydrate vegetables such as courgettes (peeled and deseeded), cooked in animal fat.
Avoid modern fruits: Today’s fruits have been hybridized into “candy growing on trees,” sometimes containing up to 25% sugar. Only a few wild berries (like mountain blueberries) remain acceptable.
Limit oilseeds (almonds, walnuts) and dairy products, which can trigger inflammation, skin problems or autoimmune diseases in some people.
Sport and metabolic flexibility
Contrary to current sports dogma, it’s not necessary to load up on sugar before or during exercise. Endurance athletes who train fasted develop genuine metabolic flexibility. The infamous “marathon wall” occurs precisely when the body, accustomed to fueling itself with sugar, depletes its glycogen reserves and proves unable to efficiently oxidize fats.
For strength or high-intensity training (Zone 5), the muscle uses its own intramuscular lipid droplets. Once adapted, the body produces its own glucose via gluconeogenesis for explosive efforts, without needing external sources.
Contraindications and poor tolerance
If the transition to a ketogenic diet causes extreme fatigue, hair loss, or chronic problems, this generally indicates a cellular energy crisis . The person’s mitochondria (the powerhouses of our cells) are damaged by years of deficiencies, pollution, or medications.
In this specific case, or in severely malnourished individuals, a sudden switch to a ketogenic diet or fasting is contraindicated, as it will trigger a surge in cortisol and muscle breakdown. It is therefore necessary to proceed gradually, significantly increasing protein intake, or temporarily reintroducing small amounts of clean carbohydrates (such as white rice) to allow the metabolism to repair itself.
