The optimal macronutrient ratio – that is, the relative proportions of protein, carbohydrate and fat – has been the subject of intense debate for decades. Despite hundreds of studies on the topic, we still don’t know whether one special combination is best for everyone, or which ratios are best for specific medical conditions. In the absence of definitive data, much can be learned by taking the truly long-term perspective – that humans across the globe have done well on diets with widely ranging macronutrients. The Inuits in the far North traditionally ate mostly fat and protein; whereas some native populations in the tropics consumed mostly carbohydrate.
Ultimately, the choice of how to balance macronutrients is individual, influenced by culture, food availability, and personal preference. So long as adequate attention is directly to food
quality, the relative ratios are probably of secondary importance in most situations (again, excepting individuals with metabolic problems like insulin resistance). That said, it becomes increasing difficult to avoid excessive intake of processed carbohydrates as total carbohydrate rises. For that reason, many people will benefit by increasing intake of foods high in fat and protein (including plant-based sources).