Understanding Energy Balance Scientifically: From Theory to Weight Loss Practice

Energy Intake and Expenditure
In individuals of normal weight, energy intake and expenditure are in a precise energy balance through regulation by the central nervous system and neuroendocrine system.

Energy balance theories are divided into lipid regulation, glucose regulation, and temperature regulation theories. Glucose regulation theory posits that blood glucose levels are the regulatory indicator of energy balance. Temperature regulation theory states that body temperature is the primary signal for the central nervous system to control food intake. Lipid regulation theory suggests that certain fat metabolites in the plasma reach the hypothalamus via blood circulation, regulating the amount of fat stored in the body through the central nervous system.

1. Energy Intake.

Long-term consumption of high-sugar and high-fat foods easily leads to obesity. Excessive energy intake is likely the main cause of obesity in children and adolescents. However, after middle age, daily energy intake decreases while weight increases, indicating a closer relationship between decreased energy expenditure and obesity in older adults.

2. Energy Expenditure

The body's energy expenditure consists of energy expenditure during rest and expenditure caused by exercise and thermogenesis. The energy expenditure at rest is called the basal metabolic rate, which accounts for about two-thirds of the total energy requirement in adults. It is used to maintain the activities of cells, tissues, and organs, such as intracellular metabolism, cell membrane transport, and the contraction of skeletal muscle and heart, enabling the body to survive.

3. Energy Balance in Obese Individuals

Before the onset of obesity, an individual's energy is in a state of balance. Due to some reason, excessive energy intake or reduced energy expenditure leads to a positive energy balance. A positive energy balance causes energy to be stored in the body as fat, increasing body fat. Subsequently, energy intake and expenditure may again reach a state of balance at a higher level.