Why Certainty About Diet Is Structurally Impossible

Humans don't know what the "best" diet is because multiple layers of complexity and distortion stack on top of each other. We evolved as animals whose appetites were tuned for a world of sparse options, seasonal scarcity, and immediate feedback when we ate something bad, then we blew that world apart with agriculture, industry, and technology, creating tens of thousands of novel foods and engineered hyper-palatable products—supernormal stimuli designed to exceed anything found in nature—that hijack ancient drives for sweetness, fat, and salt in ways evolution never prepared us for.

At the same time, most diet-related harm now shows up as slow, chronic disease over decades rather than acute poisoning, so our dopamine reward systems and rapid energy feedback loudly reinforce choices in the moment while satiety, inflammation, and metabolic damage signals arrive years later, making inner guidance noisy and unreliable. Meanwhile, humans are wildly variable in genetics, microbiome, culture, trauma, activity, and environment, so what heals one person can harm another, yet our storytelling brains are wired to overgeneralize from personal relief or transformation into universal rules ("keto healed me, so everyone should eat this way"; "veganism changed my life, so humans are herbivores"), and these rules spread as identity markers.

Nutrition science itself is hard and slow, plagued by confounders, self-reporting errors, short trial durations, and mostly observational data, creating space for ideology to substitute for evidence and for selective interpretation to look like certainty. All of this is embedded in an economic and media system where powerful industries (meat and dairy, ultra-processed foods, supplements, plant-based packaged products, "biohacking" and wellness brands) have strong incentives to frame partial truths as total answers and to keep us oscillating between branded extremes rather than quietly settling into what works. Add cultural and religious food norms, moral beliefs about animals and nature, and the way modern medicine and infrastructure buffer us from the immediate consequences of our choices, and the result is that instead of a stable, embodied sense of what to eat, we navigate competing frameworks, each locally valid and contextually limited, with no master key.