Weight loss
Weight loss is a reduction in body mass over time, caused by changes in body water, stored energy, tissue, or their combination.
Energy balance: The relationship between energy intake, energy expenditure, and changes in stored energy. A sustained mismatch between intake and expenditure changes stored energy and often body mass.
Calorie restriction: A sustained reduction in energy intake below the amount needed to maintain body mass. It is a common dietary route to creating the energy deficit associated with weight loss.
Obesity: A chronic disease characterized by excess or dysfunctional body fat that can impair health. Intentional weight loss is often considered as treatment when excess adiposity threatens health.
Fat loss: A reduction in the amount of fat tissue in the body. It is one possible component of weight loss, but not the only one.
Basal metabolic rate: The energy the body uses at rest to maintain vital physiological functions. Resting energy use contributes to expenditure and can shift as body mass changes.
Physical exercise: Planned, structured bodily activity performed to improve or maintain fitness and health. Exercise raises energy expenditure and can help preserve fitness during weight reduction.
Sarcopenia: Progressive loss of skeletal muscle strength and mass, commonly associated with aging and illness. Unintended or poorly managed loss can include muscle, not only body fat.
Water weight: Short-term body-mass variation caused primarily by changes in fluid balance. Fluid shifts can change scale readings without a corresponding change in body fat.
Appetite: The drive to eat, shaped by physiological signals, learning, and environmental cues. Appetite can rise during weight loss, making continued energy restriction harder.
Bariatric surgery: Operations that alter the stomach or digestive tract to treat severe obesity and related disease. It can produce substantial, durable weight loss for eligible people with severe obesity.