Fattening

Fattening is the process of increasing body mass due to adipose tissue accumulation. In humans, it refers to gaining weight when energy intake exceeds expenditure, resulting in increased fat stores and often weight gain. In livestock production, fattening (often called finishing) is the final growth phase in which animals are fed to reach market weight and carcass fat levels suitable for processing and sale.

Physiology and distribution: adipose tissue expands through lipogenesis and adipocyte proliferation when energy surplus persists; hormonal signals such as insulin and, in later stages, leptin, regulate appetite and fat storage. Fat distribution varies by species, sex, and age; subcutaneous fat, visceral fat, and intramuscular fat (marbling) contribute to tissue quality and energy reserves.

Factors: genetics, age, hormones, diet composition and caloric density, physical activity, and overall health influence fattening. In livestock, the finishing diet often emphasizes high-energy feeds to accelerate weight gain and fat deposition, with management practices influencing fat distribution and meat quality. In humans, obesity risks rise with excess body fat, including type 2 diabetes, cardiovascular disease, and joint problems.

Ethical and welfare considerations: rapid or excessive fat gain can impact well-being in both humans and animals; in animals, growth rate and fat distribution affect welfare and carcass value.