Young adult typically sees one in the best physical condition: strong, sharp senses, and stamina. In middle adulthood can be accompanied a loss of strength, vision sharpness, strength, and coordination. Late adulthood can be marked by menopause and osteoporosis, a reduction in bone density, grey hair, less skin elasticity, and a loss of muscle mass resulting in an increase of body fat. Physical capacities decline, muscles become weaker and less flexible. Basal metabolism also slows resulting in a tendency of gaining weight, visual acuity also declines especially for close viewing at middle age. Women's fertility begins to decrease and drops dramatically as the ovaries produce less estrogen that culminates in menopause. Male fertility often persists throughout the life span, although it tends to decline after middle age. Despite this declines, some adults remain in excellent health and are vigorously active. To everybody's surprise, some adults may achieve physical goals well beyond those attained by many younger adults. Take for example Diana Nyad swimming from Cuba to Florida at age 64, such a rewarding achievement for people at her age. But this is only true to adults who are active and don't live in a sedentary habits. According to US Census Bureau (2005) older adults are the fast-growing segment of the population in many countries, and in the US, almost 1 in 5 people will be over 65 years of age by the year 2030. Physical changes are more pronounced at late adulthood. Bones become more brittle and hardened ligaments make movements stiffer and slower. But adults can maintain physical vigor and an active lifestyle well into old age with regular exercise and good nutrition. .
Encouraging physical activity and providing a healthy diet with proper nutrition in balanced appropriate portions helps improve individuals' biosocial development. What children/adults eat affects their skeletal growth, body shape, and susceptibility to disease not to mention overall health and growth of human.