You claim there is an optimal diet? what is it man?
I'm glad you asked. Let's try to pick bones with it.
This is a fundamental question that, when stripped of modern influences and low-quality evidence, can be addressed through the lenses of biochemistry, human physiology, and evolutionary biology.
Here is a synthesis of the optimal human diet from these perspectives.
1. The Nutrient Perspective: The "Inputs"
The optimal diet must provide all essential nutrients in their most bioavailable forms, meaning the body can easily absorb and use them.
Β· Complete Protein: Animal muscle meat, organ meats, eggs, and fish provide all nine essential amino acids in the correct ratios for human tissue building and repair. Plant proteins are incomplete and less bioavailable.
Β· Bioavailable Fats: Animal fats and seafood provide essential fatty acids (DHA, EPA, ARA) in their pre-formed, active states. They are crucial for the brain, nervous system, and cell membranes. The conversion of plant-based ALA (e.g., from flax) to DHA/EPA is inefficient in humans.
Β· Bioavailable Micronutrients:
Β· Heme Iron (from meat) is far more absorbable than non-heme iron (from plants).
Β· Vitamin A (Retinol) from liver, eggs, and dairy is immediately usable, while conversion of Beta-Carotene (from plants) to Retinol is inefficient and genetically variable.
Β· Vitamin B12 is exclusively found in animal foods.
Β· Vitamin K2 (crucial for directing calcium to bones and teeth) is found in animal fats, organ meats, and fermented foods, not in plants (which provide K1).
Β· Minerals like Zinc and Calcium from animal sources are significantly more bioavailable than from plant sources, which contain mineral-binding phytates.
Conclusion from this perspective: A diet centered on animal-sourced foods provides a complete, dense, and highly bioavailable nutrient profile.
2. The Metabolic Perspective: The "Engine"
This concerns how the body derives and utilizes energy.
Β· Stable Energy and Hormonal Regulation: The primary human hormones for fuel storage and use are insulin and glucagon. A diet low in refined carbohydrates and sugars minimizes large insulin spikes, promoting metabolic stability. Fat and protein provide a slow, steady release of energy.
Β· Mitochondrial Efficiency: Our cellular powerhouses can run on both glucose (from carbohydrates) and ketones (from fats). A diet that includes periods of lower carbohydrate intake encourages metabolic flexibilityβthe ability to efficiently burn fat for fuel. This is a stable and clean-burning energy state.
Β· Satiety Signaling: Protein and fat are powerfully satiating. They trigger the release of hormones like Cholecystokinin (CCK) and Peptide YY (PYY), which signal fullness and reduce hunger, making energy intake self-regulating.
Conclusion from this perspective: A diet that minimizes blood glucose and insulin volatility by deriving a significant portion of its energy from fat and protein is metabolically stable and promotes satiety.
3. The Biological Perspective: The "Machinery"
This examines human digestive anatomy and physiology.
Β· Dentition: Human teeth are not specialized for grinding tough plant matter like those of herbivores (e.g., flat molars of cows). Our canines and incisors are suited for tearing animal flesh and fruit.
Β· Gut Morphology: Humans have a simple, acidic stomach and a relatively long small intestine, which is the primary site for nutrient absorption. This is characteristic of an omnivore with a carnivorous leaning. We lack the specialized fermenting chambers (like a rumen or enlarged cecum) of herbivores needed to break down cellulose.
Β· Digestive Enzymes: We produce proteases and lipases for breaking down protein and fat, and amylase for carbohydrates. However, we lack the enzyme systems to break down fibrous plant matter (cellulose, hemicellulose).
Conclusion from this perspective: Human biology is that of a facultative carnivore or omnivorous generalist, with clear adaptations for eating and digesting animal foods more efficiently than tough, fibrous plants.
4. The Evolutionary Perspective: The "Blueprint"
This looks at the dietary pressures that shaped our species.
Β· Encephalization: The most dramatic event in human evolution was the tripling of our brain size. This required a dense, reliable source of energy and specific building blocks. The brain is ~60% fat and requires large amounts of DHA, EPA, and cholesterol. The "shore-based diet" or "aquatic ape" hypotheses, while debated, point to the consumption of fish and shellfish as a critical source of these brain-specific nutrients, which are scarce in terrestrial diets.
Β· Persistence Hunting & Scavenging: Evidence suggests early humans accessed calorie-dense fatty meat and marrow by scavenging carcasses or running down prey. This provided a high-energy return for effort, unlike gathering low-calorie fibrous plants.
Β· Tool Use & Fire: The development of tools for hunting and butchering, and the control of fire for cooking, made animal foods even more central. Cooking denatures protein and breaks down connective tissue, making meat far easier to chew and digest, and increasing its net energy yield.
Conclusion from this perspective: The shift to a nutrient-dense, animal-based diet was not just a side note but the central driver that enabled the evolution of the large human brain and our unique cognitive abilities.
Synthesis: The Optimal Human Diet
Based on these four pillars, the optimal human diet is:
An Animal-Based Diet.
This is not a modern "carnivore diet" fad, but a template derived from first principles. Its core components are:
1. Animal Foods as the Foundation: Meat (especially red meat for its nutrient density), organ meats (the most potent source of vitamins), fish, eggs, and full-fat dairy (if tolerated). These provide complete protein, bioavailable vitamins and minerals, and essential fatty acids.
2. Low in Plant Toxins and Anti-Nutrients: It minimizes or eliminates grains, legumes, and seeds, as these plants contain defense chemicals (lectins, phytates, oxalates) that can interfere with nutrient absorption, irritate the gut, and contribute to inflammation in susceptible individuals.
3. Low in Refined Carbohydrates and Sugars: It avoids modern, processed foods that disrupt metabolic regulation.
4. Includes Seasonal Fruits and Non-Toxic Vegetables Optional: When available, these can provide variety and some phytonutrients, but they are not essential for survival or optimal health based on the biological and nutrient perspectives. They were likely seasonal, opportunistic foods for our ancestors.
In essence, the optimal human diet is one composed of the most nutrient-dense, bioavailable foods that our species is biologically adapted to consume and that promote stable metabolic function. The evidence from these core disciplines consistently points to animal-sourced foods as the centerpiece of that diet.
