Dr. Tamas Horvath, chair of the Department of Comparative Medicine at the Yale School of Medicine, succinctly puts it: “Our default is to put on weight.”
While this captures a key insight from his neuroscience research, highlighting how hypothalamic circuits evolved to promote hunger and energy storage as a survival mechanism in environments of scarcity (where prioritizing intake prevented starvation), I resist interpreting it as nature's overriding blueprint.
It risks being taken out of context, oversimplified, and weaponized to evade accountability.
All too often, people invoke Horvath's phrase as a handy biological excuse. This absolves the consequences of fundamentally fucking with our food supply. Industries engineer ultra-processed, hyper-palatable products loaded with sugars, fats, and additives that hijack our reward systems and disrupt satiety signals. At the same time, this shifts the burden of weight gain squarely onto individuals as if it's an inescapable genetic fate rather than a predictable outcome of environmental manipulation by food industries.
Yet, Horvath's "default" is not an inevitable drive toward endless accumulation but a conditional bias. It is a neural subroutine that activates strongly in caloric surplus, like today's always-available, engineered foods. This leads to weight gain because our brains err on the side of caution against historical famines.
This mechanism ultimately serves a grander default: homeostasis, the body's dynamic equilibrium that regulates energy, hormones, and metabolism to sustain health and adaptability, not obesity.
Nature's true priority is this homeostatic health, achieved through:
Natural inputs (nutrient-dense, whole foods that signal satiety properly),
Adaptation (metabolic flexibility to burn or store as needed), and
Cyclical habitats (feast-famine rhythms, seasonal shifts, and circadian cycles that reset setpoints and prevent drift).
Arguing from evolutionary logic, if perpetual weight gain were the intent, it would sabotage survival:
Excess fat slows mobility (reducing escape efficiency by up to 10% per extra 10 kg, per biomechanical studies),
Fosters metabolic inflexibility (insulin resistance that hampers fuel-switching in stress), and
Heightens vulnerability to predators, infections, or resource shortages. These are maladaptive traits that natural selection would purge, as seen in lean ancestral fossils and balanced wild ecosystems.
Thus, Horvath's observation clarifies a modern mismatch trap. But subordinating it to homeostasis, and rejecting its misuse as an individual scapegoat, reveals nature's design for resilient balance.
It urges us to demand systemic fixes to our tainted food environment rather than accept weight gain as personal destiny or evolutionary inevitability.