Even the best science is unable to gather sufficient evidence to prove it conclusively. What our ancestors ate that is. Various theories abound. For example when we discovered fire or tamed grains might still have left tell tale signs. However to decipher the exact ratio of carbs proteins etc is well neigh impossible. Some evidence may be found by studying the eating habits of relatively undisturbed populace. Even this is at best just a guess. For we are trying to go back in time several thousand years. A time that started 2.6 million years ago and ended 10,000 years back. The palaeolithic era.
The theory is that our ancestors from this period were extremely fit. Tall, athletic, versatile and extremely healthy they would put modern man to shame. What helped them get that way? It is believed that it was a combination of walking a lot, lifting heavy objects, sprinting occasionally and of course diet.
Since organised corporations were a few million years in the future they relied on what they could find easily around them. Vegetables, fruits, meat, fat from meat and perhaps the occasional spirit. There is no evidence of grains being domesticated prior to 10,000 years ago. This is very different to the generally accepted wisdom of plenty of grains, a mix of fruits and vegetables and a low fat diet advocated by most dieticians.
Mixed with plenty of sitting in the sun (read Vitamin D) a cuisine that included a diverse range of plants, herbs, fruits and vegetables they managed to get all their minerals and Vitamins. A successful hunt ensured plenty of meat and fat. They slept early because they didn’t have access to the television with 50 channels but nothing on. They spent time in close groups sharing learning and talking. You might even dream of such a life.