What do adults tend to gain and lose during adulthood?

During adulthood, it is generally observed that individuals tend to experience an increase in fat mass along with changes in body weight. As people age, a variety of factors contribute to the accumulation of fat mass. These factors include hormonal changes, decreases in physical activity levels, and metabolic rate declining, which can lead to weight gain if caloric intake is not adjusted accordingly.

Additionally, although body weight may fluctuate due to various factors including diet and activity level, the overall trend is for adults to experience an increase in fat mass throughout various stages of adulthood. This reflects a broader understanding of how body composition shifts, emphasizing the importance of monitoring fat versus lean mass as part of health assessments.

Other options mention changes in muscle mass or fat-free mass, but during adulthood, while individuals may indeed lose some muscle mass over time due to aging and inactivity, the predominant trend is the increase in fat mass alongside body weight changes. This distinction is crucial for understanding adult health and fitness.