Long-term studies have found that extreme diets lower metabolic rates, which in tern show extreme decreases in leptin levels within an individual. The low leptin informs the body that their fat reserves are low, even when the individual has gained weight. This actually makes it easier to gain weight after fasting.

Why extreme weightloss is only temporary

Leptin is more of a long term indicator of the body's energy levels. It is possible that it promotes a remodeling of neurons in the arcuate nucleus to change the set point of people.

Grinnell College

Leptin is a satiety hormone produced by fat cells and released into the bloodstream. It signals fullness to the brain, helping to regulate eating behavior by shutting it off. Leptin receptors are found in various brain regions, including the choroid plexus, cortex, and several hypothalamic nuclei. Genetic defects in the gene responsible for leptin production can cause a false underreporting of body fat, leading to overeating and obesity.

Leptin

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

This is caused by a person or animal having two copies of the ObR gene which causes obesity due to inaccurate reports of leptin.

Inherited Obesity

Leptin is made by fat cells and insulin, which helps convey information about the body's energy reserves. The appetite neurons in the arcuate system have leptin receptors but it affects the receptors in oposite ways depending on which type of appetite neuron it is - NPY or POMC. High levels of leptin activates the appetite-suppressing POMC neurons while inhibiting the appetite-increasing NPY neurons. 

How Leptin Conveys information

Leptin in preventing long term weight loss

Based on the principles of appetite regulation, analyze the scenario below and explain the most likely physiological reason for the mice's behavior. What kind of signal is failing, and why does this failure lead to overeating?

Analysis of Appetite Regulation

Based on the case study, explain the physiological reason for the child's constant hunger and subsequent overeating.

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