Gaining or losing weight is complex and goes well beyond simple hunger. The body’s primary regulatory center for hunger is the homeostatic pathway, which consists of the POMC/CART and NPY/AgRP pathways located in the hypothalamus. The secondary regulation is the hedonic system, which we will focus on today. This system can induce hunger without a caloric deficit and is influenced by emotions related to eating and hunger. In the absence of behavioral interventions, an unrestrained hedonic pathway can make maintaining effective weight loss extremely difficult. First, let’s quickly review homeostatic pathways.

In its simplest form, the intricate homeostatic pathway regulates energy balance through a feedback mechanism similar to other endocrine and hormonal pathways, utilizing neurohormonal feedback to either increase hunger or satiety based on caloric intake and energy expenditure. For example, suppose food is not consumed for an extended period of time. In that case, ghrelin levels increase, activating the orexigenic pathway (AgRP/NPY) in the central nervous system, which ultimately leads to increased hunger and decreased energy expenditure. The opposite is also true after consuming a meal. Leptin feeds into this same pathway, based on the level of adiposity present. These pathways and their components have been discussed in prior blogs, which can be reviewed with the links below:

Sometimes referred to as emotional eating or the reward pathway, the hedonic pathway is the reason the desire to eat dessert persists, even after consuming a heavy meal. This type of hunger prompts appetite via non-homeostatic pathways (i.e., independent of ghrelin, leptin, etc.). Hedonistic hunger is often more potent and can override the homeostatic pathway. By relying heavily on emotions, habits, and external factors, dopamine creates a crossover effect and can overtake the homeostatic pathways. This multifaceted hedonic pathway explains the emotions related to food. For example, guilt after binging, shame after eating dessert, the pleasant or upsetting memories associated with food smells, and the desire for comfort foods. This is the pathway that relates to food addictions, stress-eating, and established eating habits.

The hedonic pathway has several neurologic areas of stimulation, with external inputs affecting these structures differently.

  • Pre-frontal cortex: This area involves impulse control, spontaneity, planning, and decision-making and influences personality. People who enjoy spontaneity or are considered more impulsive may be more likely to eat out or indulge in spur-of-the-moment without considering the consequences. In contrast, planners and rule-followers may be more inclined to benefit from tracking calories and show more restraint to meet their goals
  • Limbic system: This is primarily driven by dopamine and mediates cravings, rewards, compulsions, and food addiction. Persistent activation of this system leads to upregulation of receptors and adaptation of the homeostatic pathway in an attempt to provide continual dopaminergic activation, similar to what is seen with other substance addictions.

Specific portions of the limbic system that affect emotions and memories include:

  1. Amygdala: Responds to food cues (advertisements, visuals, etc.). This is where commercials and advertisements may “subliminally” influence eating patterns.
  2. Hippocampus: Activated by memories or prior experiences (e.g., the smell of a dessert reminding someone of a family celebration). This can also have a negative impact; for example, vomiting after eating a particular food may lead to a food aversion.

Patients with obesity primarily affected by the hedonic pathway can still be treated with medications and surgical interventions. For example, there have been significant improvements in binge eating severity when patients are started on a GLP-1. Theoretically, this blocks the crossover of the hedonic system at its input site into the homeostatic path, although it is likely more complex than this. Similarly, selective serotonin reuptake inhibitors can also help with binge eating, as they may alter the dopamine-serotonin balance. In short, there are pharmacologic treatment options. However, these patients also preferentially respond well to behavioral interventions such as motivational interviewing, cognitive behavioral therapy, and psychotherapy.

For the ABOM boards, you must understand the homeostatic path in detail, including the feedback system, inputs, and regulation. However, the hedonic system is also fair game, and a knowledge of its effects and locations of regulation (e.g., limbic system involvement in food addiction) must be well understood, as these two systems work in an integrative, complex manner.

Sample Question

A study utilizing a functional MRI is being conducted. Images of food are displayed to the research participant while they are in an MRI. The researcher can visualize activated areas within the brain in real-time. In one participant, a particular image activates the amygdala. Which of the following qualities of the food image likely caused this activation?

A. A memory associated with the image

B. A prior food addiction

C. Ghrelin stimulation of NPY/AgRP

D. A successful advertisement

Next Week: Supplements

Upcoming: MC4r Deficiency and OSA

For more practice questions, check out the following:

  • Obesity Medicine Board Review Questions (2026): Q 59.
  • Obesity Medicine Practice Tests (2026): Qs 265 and 286.

(Copyright 2026) Obesity Medicine Board Review Questions, LLC: obesitymedicinereview.com

Featured image: (2020, May 13). Wikimedia Commons, the free media repository.

Copyediting by Kelly Smith

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