Obesity Epidemic in Humans and Strategies for Combat in the Anthropocene

Introduction: a global challenge of evolutionary mismatch

The obesity epidemic, recognized by the WHO as one of the key public health issues of the 21st century, is a striking example of evolutionary mismatch (mismatch theory). The genotype of Homo sapiens, formed under Pleistocene conditions (about 2.6 million – 11.7 thousand years ago), has encountered a radically changed environment — the "abundance of scarcity" (obesogenic environment). This has led to a systemic failure in the regulation of energy balance. The fight against obesity today requires not just a call to willpower, but a comprehensive scientific approach that takes into account neurobiology, endocrinology, microbiology, sociology, and economics.

Roots of the problem: why does our body "break down" in conditions of abundance?

Evolutionary mechanism of the "thrifty genotype": For millions of years, natural selection favored individuals who efficiently stored energy in the form of fat during periods of abundance (seasonal fruits, successful hunting) to survive inevitable periods of scarcity. Genes that promote fat storage were adaptive. In today's world, where high-calorie food is available 24/7, these same genes have become pathogenic.

Neuroendocrine disorder: The system of regulation of hunger and satiety, with the hypothalamus as its center, is evolutionarily tuned to protect against scarcity, not abundance. Leptin ("satiety hormone"), produced by adipose tissue, becomes less effective in suppressing appetite in conditions of obesity (developing leptin resistance), similar to insulin resistance in type 2 diabetes. Ultra-processed foods "trick" ancient reward systems in the brain, leading to hyperphagia (overeating) without a sense of true satiety.

Gut microbiome: Studies in recent years have shown that the composition of the gut microbiota in people with obesity differs from that in people with normal weight. The "obese" microbiota extracts energy from food more efficiently, promotes chronic low-grade inflammation, and influences food behavior through the gut-brain axis.

Epigenetics: Inadequate nutrition and stress in parents can increase the predisposition to obesity in their children through epigenetic mechanisms (DNA methylation), creating an intergenerational vicious circle.

Why do traditional approaches ("eat less, move more") often fail?

The simplified model of "calories in vs. calories out" does not take into account the biological complexity of the process:

Metabolic adaptation: When calorie intake is reduced, the body, following ancient survival programs, does not simply burn fat, but reduces the basal metabolic rate (up to 15-20%), increases the feeling of hunger, and reduces energy expenditure on non-conscious activity (NEAT — non-exercise activity thermogenesis). This makes maintaining a calorie deficit mentally and physically torturous.

Hormonal response: Strict diets lead to a decrease in leptin levels and an increase in ghrelin ("hunger hormone"), creating a powerful biological impulse to gain weight after the end of the diet (yo-yo effect).

Modern strategies for combat: a multifactorial approach

The fight against the epidemic requires action at all levels: from molecular to public.

Individual level (medical):

Recognition of obesity as a chronic relapsing disease, not a result of laziness. This changes the approach to treatment: long-term therapy is needed, as in hypertension.

Pharmacotherapy of the new generation: GLP-1 receptor agonists (semaglutide, tirzepatide) have been a breakthrough. They not only suppress appetite but also act on the centers of satiety in the brain, normalize insulin production, and slow gastric emptying.

Bariatric surgery (gastric bypass, sleeve gastrectomy): The most effective method for severe forms. It acts not only by reducing the volume of the stomach but also through complex hormonal changes that affect food behavior and metabolism.

Personalized approaches: Taking into account genetic predisposition, type of obesity (android/gynoid), and microbiota status.

Public health and policy level:

Tax on sugar-sweetened beverages (Sugar Tax): Successfully implemented in the UK, Mexico, several EU countries. It leads to a decrease in sales and stimulates producers to reformulate products.

Clear labeling of products: Systems like "traffic light" (UK), Nutri-Score (EU) help consumers make quick conscious choices.

Limitation of advertising of harmful products for children.

Urban planning policy: Creating an environment conducive to physical activity — pedestrian and bicycle zones, accessible parks, public transport.

Changing food behavior:

Focus on quality, not just calorie count: Prioritizing whole, minimally processed products (vegetables, fruits, legumes, whole grains, quality proteins and fats), which provide satiety and normalize hormonal response.

Mindful eating: Techniques aimed at restoring the connection with natural signals of hunger and satiety.

Work with psychological factors: Treatment of eating disorders, compulsive overeating, work with stress, which is a powerful trigger for weight gain.

Interesting facts and examples

The paradox of the island of Nauru: After receiving income from phosphorus mining, the indigenous population of this Pacific island switched abruptly to imported high-calorie food. In just a few decades, the level of obesity and type 2 diabetes reached 90%, becoming a catastrophic example of the speed of the epidemic when the environment changes.

The "setpoint" effect: A theory about the presence in each person of a genetically determined "setpoint" weight that the body strives to maintain. Compensatory mechanisms are activated when there is a significant deviation.

The "The Biggest Loser" study: Longitudinal observation of participants in the show who lost dozens of kilograms showed that after 6 years, the weight of most returned, and the basal metabolism remained reduced by hundreds of calories per day — a vivid demonstration of metabolic adaptation.

The success of Chile: The country, introducing strict legislation (black warning labels on products with high sugar, salt, and fat content; ban on advertising and sale of such food in schools), achieved a significant reduction in the purchase of harmful products by the population.

Conclusion

The obesity epidemic is a systemic crisis caused by the collision of our ancient biology with the modern, human-made environment. Effective combat against it is impossible through accusations and simplified solutions. It requires:

Medicalization of the approach: Recognizing obesity as a complex chronic disease.

Scientifically justified interventions: From new classes of drugs to surgery.

Changes in the environment (creation of "healthy choice is the easy choice") through state policy.

Deep work with food behavior and psychology.

The future lies in the integration of these approaches. Personalized medicine, taking into account genetics and microbiome, combined with thoughtful social policy capable of countering the economic interests of food industry giants, is the only way to stop this silent pandemic. Humanity has created an environment leading to obesity; now it must use scientific reason and collective will to redesign this environment in accordance with its own health and well-being.
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