The 2025 Levels guide to hunger — and how to manage it

Hunger is a natural (and essential) feeling, but it shouldn’t rule your life. Here’s why you might feel hungry all the time and how to manage it with specific nutrients, foods, and habits.

Given the soaring popularity of glucagon-like peptide 1 (GLP-1) agonists like semaglutide (name brands Ozempic and Wegovy), which promote weight loss by strongly suppressing appetite, it’s clear hunger plays a significant role in our ability to regulate weight and overall health.

While this is intuitive, hunger is anything but simple. This sensation is a survival mechanism driven by a complex and finely tuned web of physical, neurological, and hormonal signals, all influenced by what and how much you eat, body fat, physical activity, stress, sleep, and much more. Additionally, although a need for energy (calories) is a primary driver of hunger, not all calories regulate hunger in the same way—specific foods and food combinations have different effects on hunger and fullness sensations depending on factors like macronutrient composition (fat, protein, carbs) and form (solid versus liquids).

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This article breaks down the science of physiological hunger—what’s going on within the body that drives this sensation, how different macronutrients and levels of food processing impact hunger and fullness, and the lifestyle factors and habits that can either promote or quell hunger. (This is related to but unique from appetite, which is a more psychological craving for food.)

The cycle of feeling hungry, which drives you to seek and eat food, followed by feeling satisfied once you’ve eaten (what we call satiety), is a complex sequence of events. It involves the interplay of hormones from the gastrointestinal (GI) tract and the hypothalamus of the brain, along with the transmission of neural information along the gut-brain axis (from the stomach and intestines to the brain stem via the vagus nerve). Understanding these processes will help you better grasp the mechanisms by which specific nutrients, foods, and habits influence hunger and satiety, which we’ll dive into later.

When the stomach is empty and circulating insulin and blood glucose levels are relatively low, such as during periods of fasting or between meals, X/A-like cells in the lining of the stomach secrete a GI hormone called ghrelin. Your body may also release it in response to food cues (e.g., seeing a picture of food or walking by your coworker’s lunch). Ghrelin is often called the “hunger hormone” and is considered orexigenic, meaning it stimulates appetite. It gets you to eat in a couple of ways:

Two more orexigenic neuropeptide hormones that stimulate appetite, particularly for highly palatable foods, are orexin (OX) and melanin-concentrating hormone (MCH), which are secreted by neurons in the lateral hypothalamus.