Unlike most herbivores, we have a single stomach. The human GI tract can absorb virtually every nutrient in meat, and Vitamin B12, which is essential to human health, is found only in foods of animal origin. The problem with the American diet is not too much meat, protein and fat, contends the Protein Couple. The problem is too much sugar, starch and carbohydrate. The more sugar in your blood, the more elevated your insulin.
Excess insulin can lead to obesity, diabetes and high cholesterol.
Insulin is not a villain. You need it to survive. Insulin becomes a problem when you have either too little or too much. It's the hormone that signals the body to store fat and make cholesterol. Michael Eades came by this knowledge empirically.