The body's adjustment of energy expenditure during weight loss and maintenance involves multiple biological mechanisms that change over time, and these different phases require distinct scientific...
Mechanism
Synthesis from 1 study
When you lose weight, your body slows down its energy use in three different ways: first by losing water and stored sugar, then by making your organs work less hard, and finally by making your muscles use less energy when you move — all of this is shown in the same study tracking people through...
Most probable mechanism
When you lose weight, your body lowers its energy use in three different ways depending on how far along you are: early on, it loses water and glycogen, which makes your resting metabolism drop; later, your organs like your liver and heart slow down their activity, burning less energy even at rest; and after you’ve lost the weight, your muscles become more efficient at moving, so everyday activities use less energy — all of this is documented in studies tracking metabolic changes during dieting (10.1002/oby.23703).
Caloric restriction reduces plasma insulin and increases glucagon, triggering glycogen depletion and loss of bound intracellular water, which lowers resting energy expenditure independently of fat loss (10.1002/oby.23703)
Prolonged energy deficit shifts substrate use to lipid mobilization, which is associated with reduced metabolic activity in high-energy organs including the liver, kidneys, and heart, as evidenced by decreased urea production, glomerular filtration rate, heart rate, and core body temperature (10.1002/oby.23703)
During weight maintenance, persistently low levels of leptin and triiodothyronine suppress sympathetic nervous system activity, leading to improved skeletal muscle mechanical efficiency during low-intensity movement, thereby reducing nonresting energy expenditure (10.1002/oby.23703)
Evidence from Studies
Supporting (1)
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Changes in body composition and homeostatic control of resting energy expenditure during dietary weight loss
Contradicting (0)
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Gold Standard Evidence Needed
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