Energy regulation

• Energy requirement: amount of energy intake needed to maintain energy balance
• Energy balance: energy balance-energy intake = energy expenditure
• Positive energy balance: Energy intake > energy expenditure.
• Negative energy balance: energy intake < energy out
• Energy expenditure: 1: basal energy/metabolism: minimal energy required to support body functions in absence of physical activity or food intake (resting energy expenditure is more common)
• energy expenditure: 2: thermic effect of food: energy with absorptive state
• Energy expenditure: 3: physical activity: sum of energy for all types of PA/movement
• brain, skeletal muscle, and liver are most metabolically active tissues
• CNS (mainly hypothalamus) receives signals to control energy balance from insulin, leptin, ghrelin
• Afferent signals come from meal, adipose, pancreas, stomach and SI to regulate energy
• Despite many signals to stop eating, there is a bias towards weight gain