This is a very deep question that touches on biology, psychology, sociology, and history. The answer is not as simple as "it's fashion," but rather a complex combination of factors.
Biological basis: instincts and evolution
At a fundamental level, the preference for thinness (as an indicator of health and fertility) is rooted in deep evolutionary logic.
Indicator of health and fertility.For most of human history, excess weight was rare, and obesity was a sign of illness. A slender figure subconsciously signaled good metabolism, the absence of chronic diseases (such as diabetes or heart problems), and, most importantly, high reproductive ability. For ancient men, choosing such a partner increased the chances of healthy offspring.
Symbol of youth.Slenderness is often associated with youth, and youth with the peak of fertility. Features characteristic of a young body — a thin waist, a certain ratio of hips to waist (so-called WHR) — are universal signals attractive to men in different cultures.
Instinct of "quality of resources."In ancient times, a woman with a slender and agile body was perceived as a more effective hunter-gatherer and hearthkeeper, capable of performing physical work. This was an indirect sign that she could contribute to the survival of the family.
Socio-cultural influence: ideals and status
Biology explains basic preferences, but their specific expression is shaped by society.
Media and fashion industry.For decades, glossy magazines, cinema, and television have promoted the image of a slender, often thin woman as the epitome of success, beauty, and sexuality. This image has penetrated so deeply into mass consciousness that it has become perceived by many as a "natural" norm.
Social status.In modern Western society, thinness often correlates with such socially desirable qualities as self-discipline, success, and access to healthy food. Conversely, excess weight may (often unfairly) be associated with laziness, low income, and lack of ed ...
Read more