Dietary protein beyond its saturation (eg., >1.5g/kg body weight) can become a taxing macronutrient if not considering the below biochemistry. You require healthy kidneys and liver to clear excessive nitrogen through the urea cycle (tied to mitochondrial TCA cycle and NAD/NADH ratio) which requires magnesium-ATP, manganese (not found in animal protein except shellfish, a big problem for most carnivores), potassium (found in juices of cooked muscle meat if salvaging), and vitamin B6. There's also the consideration around excess methionine requires to be balanced with glycine due to the glycine buffer system (GNMT). Excess methionine and cysteine get shunted down the transsulfuration pathway which makes hydrogen sulfide (H2S) and sulfite — both can be toxic where they can cause mitochondrial dysfunction, NADPH depletion, mast cell degranulation, neurotoxicity, and depletion of various B vitamins like B1, B6, and B9. If you don't get sufficient molybdenum in your diet (unlikely unless you consume legumes) to accompany that high protein, you can't clear the sulfite (this also requires iron and B2). In order to clear H2S, a healthy mitochondrial respiratory chain is needed with an optimal CoQ/CoQH2 ratio within the free pool of the ETC, this process also requires B2 and glutathione. Any spillover of protein also feeds into gluconeogenesis which is energetically expensive where you spend 6 ATP to make glucose, which can be easily attainable from carbohydrates instead. The signal for this to occur requires a pulse of cortisol and glucagon, whilst magnesium, B6, and B7 (often gets missed) are nutrient cofactors. Sufficient dietary carbohydrates bypass this. Excess protein is also taxing on the digestive system. If you lack sufficient stomach acid (or production takes a toll due to excess protein) to properly break it down, you end up with undigested proteins that can cause symptoms like reflux, bloating, nausea, dysbiosis, and even nutrient deficiencies (a lot of micronutrients are embedded inside the matrix of animal protein). You need B1, salt/chloride, choline, B5, zinc, potassium, magnesium-ATP, and bicarbonate/carbon dioxide for stomach acid production. There can be big problems with excessive protein when you don't take these layers into consideration. Most don't. Magnesium, zinc, potassium, lipoate, calcium, B1, B2, B3, B5, and B7 are all hugely important for glucose utilization and oxidation. Most do well with the incorporation of cinnamon, apple cider vinegar, and pairing carbohydrates with some fiber, proteins, and fats (Peat wisdom, run MCTs to prevent activation of the Randle cycle through malonyl-CoA blocking CPT1).