The first issue there straight away is the seemingly standard thought that a low carb diet is high in protein. Protein intake averages around 20-30% of hunter-gatherer diets and should not exceed 35% or risk of 'protein poisoning' occurs. The majority of calories on a low carb diet are therefore from fat. HG tribes have been known to discard lean meat or even whole kills if the meat is to lean and there is nothing else to make up calories with, such as tubers, berries or another source of fat. So 'excess glucagon' should not occur on a balanced low carb diet. The release of cortisol in response to glucagon is also limited, and simply serves to stimulate many of the same responses as glucagon, especially gluconeogenisis. It is not at muscle wasting proportions, especially when you have plenty of fat flowing around being used for energy.
Controlling insulin levels is done well on the zone, but can be even better on even lower carbs, especially those with a 'broken' metabolism and the majority of the population showing some signs of insulin resistance. Drastically reducing fructose is also important in achieving this.
The macro-nutrient intakes of HG diets vary greatly depending on geographical location, from almost zero carb of Eskimos living of frozen fish, caribou, and other large game, to the high carb Kitvian and some Indian tribes. Okinawans in Japan live on sea vegetables, seafood, rice (easily digested) pork, lard and some soy. During certain times of the year the Masai live on fresh milk, blood and meat, and their warriors can take down a lion with a spear. In fact the average carb intake of HG's is around 20-40%, the very top range of which is the zone.
The one thing all these cultures have in common is the fact that their diets are made up of purely whole foods, minimal/no grains (or at least gluten free), low fructose, adequate protein and fats from animal sources and always a good N-6:N-3 ratio. So is there a certain ratio that the body prefers to optimise hormonal control? Possibly, but unlikely considering the wide range of niches humans have occupied and thrived on such different ratios while displaying little to no signs of modern diseases and inflammation regardless of ratio followed, until they start eating modern foods and following a modern lifestyle.
As far as health and longevity is concerned humans have evolved to eat nutrient dense diets i.e. meat and fat/low carb. A keto adapted individual can physically perform extremely well, especially in endurance. When talking metcons though, a bit of glycogen replenishing beforehand may give you that extra perk, especially if performing multiple workouts in one day. If you don’t want to be the next CF games champ though and long term health is as much a priority as immediate performance, then maybe slightly lower carb is preferable. I personally am still making PB's in all metcons after following a very low carb diet for around 6 months now. Referring to a diets ability to produce ATP and mitochondrial function, this is not specific to a certain macro-nutrient ratio; this is simply from eating the right foods, reducing inflammation and a good EFA balance. In fact a low carb - high fat diet increases the amount of mitochondria in the cells to increase beta-oxidation of fats for energy.
So to summarise:
1. Insulin control can be achieved and maintained easier on a low carb diet, ensuring all other hormonal processes stay in check.
2. Humans can thrive on a variety of different ratios as long as the foods are in line with our genome.
3. Performance can be improved when keto adapted and extra carbs can be used for recovery (depending on goals) or before a major event.
4. Weighing and measuring meals is not necessary for good performance if hormones are already under control through diet, but can help the perfectionist or for absolute accuracy for a top performer.
5. This is certainly not to say that the zone doesn’t work, just that it can be done as well or better through a personalised application of Paleo.
I'll get into inflammation, EFA's and Eicosanoids, which is the heart of the zone, soon.