In the world of skin health and longevity, practitioners often focus on nutrients, serums and supplements that promise youthful results. Yet, few pause to ask a more fundamental question: are we even feeding the human body according to its biological design? Evidence from evolutionary biology, nutritional science and dermatological nutrition suggests that our species thrives best on a diet aligned with our anatomy, physiology and biochemistry, one that is overwhelmingly plant-based, particularly rich in fruits.
Rethinking Human Nutrition
Humans have long been labelled “opportunistic omnivores”, capable of eating almost anything. While this flexibility may have ensured survival in times of scarcity, it does not necessarily mean it promotes health, longevity or dermal vitality. The idea that “we can eat anything” is increasingly contradicted by epidemiological evidence linking modern Western diets, high in meat, dairy and processed fats but low in fruits and vegetables, to inflammation, premature ageing and degenerative skin changes.
Every species has a diet that suits its design. True carnivores secrete enzymes such as uricase to process the high purine load from animal flesh. Humans do not. Instead, uric acid accumulates, driving systemic inflammation that accelerates skin ageing and collagen breakdown. Our lack of uricase is a biochemical clue that meat-heavy diets are incongruent with human physiology.
Every species has a diet that suits its design. True carnivores secrete enzymes such as uricase to process the high purine load from animal flesh. Humans do not. Instead, uric acid accumulates, driving systemic inflammation that accelerates skin ageing and collagen breakdown. Our lack of uricase is a biochemical clue that meat-heavy diets are incongruent with human physiology.
Eat food.
Not too much.
Mostly plants.
Not too much.
Mostly plants.
Skin Ageing and Evolution: How Trichromatic Vision Reveals Our Optimal Diet
Humans carry several evolutionary clues that point to a plant-focused diet. Biochemically, we lack certain enzymes and synthetic pathways present in many other mammals. For example, uricase, found in true carnivores and omnivores, breaks down uric acid from purine metabolism. Without it, uric acid accumulates, promoting inflammation, oxidative stress, and conditions such as gout and cardiovascular disease. For the skin, this manifests as dullness, impaired healing, and accelerated ageing. Similarly, humans cannot synthesise vitamin C, a critical antioxidant for collagen synthesis, wound repair, and photoprotection. Our dependence on dietary vitamin C implies that our ancestors consumed abundant fruits and vegetables to meet this need. Today, insufficient intake leaves skin more vulnerable to oxidative damage and premature ageing.
Anatomically, our trichromatic vision reinforces this evolutionary message. Humans have three colour receptors, tuned to red, green, and blue, a trait shared with other fruit-eating primates. This adaptation allowed our ancestors to detect ripe, nutrient-dense fruits against a backdrop of foliage. It also explains our innate attraction to the vibrant colours of fresh produce, which correspond to the presence of antioxidants such as carotenoids and flavonoids. In the context of dermatological nutrition, these pigments do more than please the eye, they protect the skin from UV stress and support a luminous, even complexion.
The Human Digestive Design
Anatomical comparisons between humans and other primates also reveal our digestive tract to be that of an unspecialised frugivore. Studies published in Human Evolution (2002) show that the human gut, when adjusted for body size, is far more similar to fruit-eating apes than to carnivorous or even omnivorous species. Our relatively long small intestine, moderate stomach acidity and microbial fermentation capacity favour the digestion of plant matter rich in fibre, water and phytochemicals.
Indeed, analyses of fossilised human faeces, affectionately known as “paleo poop”, show fibre levels four to five times higher than those seen in the modern diet. Such fibre content is only achievable with vast quantities of plant foods. These findings suggest that early humans did not live on meat and marrow but on fruits, leaves, nuts and seeds. The industrial and agricultural revolutions may have altered our food environment, yet our physiology remains that of a fruit-eater.
Uricase: The Forgotten Enzyme
One of the most compelling biochemical clues that humans are not designed for high meat consumption lies in our lack of uricase. This enzyme, present in true carnivores and omnivores, breaks down uric acid, a by-product of purine metabolism found abundantly in animal protein. Without uricase, uric acid levels rise, contributing to inflammation, oxidative stress, and conditions such as gout and cardiovascular disease. For the skin, this biochemical imbalance manifests as dullness, premature ageing, and impaired healing due to chronic low-grade inflammation. From an evolutionary standpoint, the loss of uricase suggests that our ancestors’ diets were naturally low in purine-rich foods, aligning more closely with a plant-based, fruit-dominant nutritional model.
ACCORDING TO SOME THEORIES, OUR VISUAL
SYSTEM EVOLVED TO EASILY IDENTIFY
PARTICULARLY NUTRITIOUS BERRIES, FRUITS
AND VEGETABLES FROM JUNGLE FOLIAGE
Vitamin C: The Collagen Catalyst We Stopped Making
Equally significant is our inability to synthesise vitamin C, a trait we share with other frugivorous mammals such as fruit bats and primates. This powerful antioxidant is vital for collagen synthesis, wound repair, and photoprotection. Most mammals produce it internally, yet humans must rely entirely on dietary sources. Evolution only discards a metabolic pathway when it is redundant, implying that our ancestral diet supplied such abundant vitamin C from fruits and vegetables that endogenous production became unnecessary. In modern times, when fruit intake is often inadequate, this lost ability becomes a liability, leaving skin more vulnerable to oxidative damage and accelerated ageing. Regular consumption of vitamin C-rich plant foods like citrus, kiwis, papaya, and leafy greens remains fundamental to skin integrity and youthful resilience.
Malnutrition in Modern Abundance
Malnutrition is often misunderstood as under-eating, but it includes over-eating nutrient-poor foods. The typical Western diet is high in calories yet low in micronutrients, fibre and phytochemicals. This mismatch between energy intake and nutrient density drives oxidative stress, inflammation and premature ageing, both systemically and within the skin. A nutrient-poor diet depletes antioxidants like vitamins C and E, accelerates glycation and weakens the skin barrier.
In contrast, a diet rich in colourful plant foods supplies the full spectrum of antioxidants, carotenoids, flavonoids and polyphenols that protect the skin against UV damage and free radicals. These compounds also modulate the gut–skin axis by supporting beneficial microbiota and reducing systemic inflammation. The result is improved dermal elasticity, reduced fine lines and enhanced luminosity, outcomes no topical treatment can fully replicate.
MAN’S STRUCTURE, INTERNAL AND EXTERNAL
COMPARED WITH THAT OF THE OTHER ANIMALS,
SHOWS THAT FRUIT AND SUCCULENT VEGETABLES
ARE HIS NATURAL FOOD
Beyond Food Groups: Nutrients that Matter
Conventional dietary guidelines are shaped more by agricultural economics than by human biology. The idea of “food groups” originated in 1943 as a wartime survival tool, not as a reflection of optimal health. From a biochemical standpoint, the body recognises nutrients, not food categories. It requires fuel (kilocalories), macronutrients (proteins, carbohydrates and fats), micronutrients (vitamins and minerals), fibre, hydration and phytochemicals. All of these can be sourced entirely from plants.
The Skin Nutrition Institute identifies five “facelift food” groups: micronutrients, macronutrients, fibre, hydration and phytochemicals. Each can be met with fresh, whole plant foods. For example, amino acids for collagen synthesis are abundant in leafy greens and legumes, calcium in oranges and sesame seeds and iron in strawberries and lentils. Nature provides complete nourishment without reliance on animal-derived foods.
The Skin Nutrition Institute identifies five “facelift food” groups: micronutrients, macronutrients, fibre, hydration and phytochemicals. Each can be met with fresh, whole plant foods. For example, amino acids for collagen synthesis are abundant in leafy greens and legumes, calcium in oranges and sesame seeds and iron in strawberries and lentils. Nature provides complete nourishment without reliance on animal-derived foods.
The Anti-Ageing Mechanisms of a Plant-Rich Diet
A species-specific diet aligned with human biology naturally supports anti-ageing at multiple levels:
- Reduced oxidative stress: Fruits and vegetables deliver potent antioxidants that neutralise reactive oxygen species, a key driver of skin ageing.
- Improved collagen stability: Vitamin C, silica and plant polyphenols enhance collagen cross-linking and reduce matrix degradation.
- Optimised hydration: High-water-content foods like cucumber, melon and citrus improve intracellular hydration and skin turgor.
- Balanced inflammation: Phytochemicals like quercetin and curcumin modulate inflammatory pathways associated with acne, rosacea and ageing.
- Enhanced detoxification: Fibre and chlorophyll aid hepatic and gastrointestinal elimination, reducing systemic toxic burden visible in the skin.
This integrative effect explains why populations consuming predominantly plant-based diets, such as the traditional Okinawan or Mediterranean diets, exhibit delayed ageing and lower rates of skin-related inflammation.
A Call for Professional Reorientation
For professionals in nutrition, beauty and dermatology, understanding diet through an evolutionary lens is essential. The future of skin health lies not merely in topical innovation but in aligning dietary practice with our species’ natural design. Dietary patterns that make biological sense will always outperform reductionist nutrient supplementation or restrictive regimes.
To advocate for youthful, resilient skin, practitioners must move beyond calorie counts and food groups toward species-specific nutrition. Encouraging clients to eat in accordance with their anatomy, to fill their plates with fruits, vegetables, nuts and seeds, honours both human evolution and the science of dermal vitality.
After all, diet is the new dermatology.
Continue your professional learning.Explore the Skin Nutrition Science Glossary, a growing resource designed for practitioners in aesthetics, nutrition and wellness science.
Article by Star Khechara
Professional agehacker, author, speaker, founder of skin nutrition institute
About me
Ex-skincare formulator and beauty author turned skin-nutrition educator: Star distilled her 20+ years of skin-health knowledge into the world’s first international accredited skin-nutrition school to teach skin therapists, facialists, face yoga practitioners and estheticians how to help their clients feed the skin from within for cellular-level rejuvenation and vibrant beauty.
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