Reading through the last thirty or so posts (I don’t check this thread all that frequently), I see some possible confusion that could stand to be cleared up.
The first point is that most meats are about 25% protein (roughly speaking), or about 7 grams of protein per ounce. There is a big difference between eating 300 grams of meat–about 10.5 ounces, which would contain 75 g of protein–and 300 grams of protein—which, in the form of meat, would come to about 1.2 k / 2.6 lb of meat.
Second, protein recommendations vary, and every expert appears to have a different opinion. The unavoidable nitrogen loss from daily living appears to average out to a daily requirement of 0.6 g protein per kg of lean body mass. A few outliers can make do with less, and a few require a lot more protein, as a minimum. If your muscles start wasting, then you need more protein than you are getting. If you start smelling of ammonia, you are getting too much and should cut back. (Remember that protein is our dietary source of nitrogen, because every amino acid contains at least one nitrogen molecule. Fats and carbohydrates contain no nitrogen whatsoever.)
The recommendations vary for different reasons. Dr. Ron Rosedale recommends only enough protein to make up for the inevitable nitrogen loss, because he is concerned with longevity and protein intake stimulates mTOR. Prof. Benjamin Bikman recommends up to 2 g/kg LBM/day, because he is concerned about the loss of muscle mass as we age. Most recommendations fall between these two extremes, and Richard Morris’s official recommendation here on KF is still, I believe 1.0-1.5 g/kg. The Virta Health site contains tables based on total body weight that give recommended protein intakes in this range, so you don’t have to do the arithmetic.
Third, remember that all this is approximate, and that individual variation can be significant.
Fourth, it appears that we have an instinct for getting a good amount of protein (this is known as the Simpson-Raubenheimer Protein-Leveraging Hypothesis), so if you are happy with how much you are taking in, then don’t worry about it.
Fifth, the old notion that excess protein intake is automatically and inevitably converted into glucose by the process called “gluconeogenesis” has been shown to be inaccurate. Apparently, while the real story is quite nuanced, it is more helpful to think of gluconeogenesis as more of a demand-driven process than a supply-driven one.
Sixth, the body can store only a limited amount of amino acids (just as carbohydrates are strings of glucose molecules, so all proteins are arrangements of various amino acids), there is no real point to eating more protein than necessary. Amino acids that can’t be stored in the labile pool are deaminated (the nitrogen is removed and excreted)
Seventh, every protein has a life cycle (the duration ranges from seconds to years, depending on the protein), so every protein needs at some point to be disassembled and reconstructed, especially once it becomes damaged. This process is called autophagy. There is always some autophagy occurring, but fasting and a ketogenic diet are well-known ways of facilitating this process.
Lastly, the effect of protein intake on insulin secretion depends on the rest of the diet. In a diet with a great deal of carbohydrate intake, the rise in insulin from consuming excess protein can be significant. In a low-carbohydrate milieu, however, the rise in insulin is matched by an increase in glucagon, so that the insulin/glucagon ratio remains unchanged.