The author’s term for the widely accepted but flawed belief that obesity is purely a caloric imbalance governed by the “Calories In, Calories Out” formula. He argues that this simplistic perspective ignores the primary role hormones play in determining how the body uses food energy. The author contends that obesity is a hormonal imbalance, making the type of food eaten more important than its caloric content.

Hunger that arises as a learned, physiological response to external cues rather than from a metabolic need for nutrients. Fung argues that through repeated association, triggers like the time of day, a specific location (e.g., a movie theater), or a social situation can make a person feel hungry. This type of hunger is driven by habit and environment, distinct from the physical signals of homeostatic hunger or the pleasure-seeking of hedonic hunger.

The automatic, habitual state of either eating or not eating that requires no willpower to maintain. The author argues that in the 1970s, the societal default was “not eating” except at structured mealtimes, making snacking an effortful choice. In the modern food environment, the default has become “eat all the time” (188), which requires significant willpower to avoid constant consumption.

The practice of using food to soothe or suppress negative emotions like sadness and stress, or to enhance positive ones. As a key component of hedonic hunger, it is a coping mechanism where food, particularly ultra-processed “comfort food,” provides temporary pleasure by inducing a dopamine spike. The author contends that emotional eating drives consumption patterns that calorie-counting cannot address.

The two distinct metabolic states the body occupies. In the fed state, which occurs while and after eating, high insulin levels signal the body to store food energy as fat or glycogen. In the fasted state, which occurs when not eating, low insulin levels signal the body to burn its stored energy. The author emphasizes that the body cannot burn stored fat while in the fed state, making regular periods of fasting essential for weight loss.

A state in which certain foods, typically ultra-processed, trigger a repetitive and hard-to-quit pattern of consumption. The author argues that certain foods trigger a physiological response engineered to produce a “supernormal stimulus” and rapid dopamine spike, similar to addictive drugs. Key signs include cravings, loss of control over consumption, and continued use despite recognized harm.

The physical structure in which a food’s nutrients are naturally embedded. The author explains that this structure affects the speed of digestion and absorption, which in turn influences a food’s hormonal impact. Processing disrupts the food matrix, making nutrients more rapidly digestible and thus more likely to cause an insulin spike. Whole foods have a more complex matrix leading to slower digestion and a lower insulin response.

The author’s three fundamental principles for achieving and maintaining a healthy weight. The rules are: 1) Avoid ultra-processed foods; 2) Don’t eat all the time and fast regularly; and 3) Commit to a health mindset and healthy social habits. These principles form a comprehensive system designed to manage all three types of hunger: homeostatic, hedonic, and conditioned.

The drive to eat for pleasure, comfort, or reward, as distinct from the body’s metabolic need for energy (homeostatic hunger). This type of hunger is driven by the brain’s reward centers and is a major factor in food addiction and emotional eating. The author argues that modern ultra-processed foods are specifically designed to stimulate hedonic hunger, leading to overconsumption.

The physical drive to eat to maintain the body’s stable internal environment and acquire necessary nutrients. This form of hunger is regulated by the neurohormonal system Fung calls the “body fat thermostat,” which sends signals of hunger and satiety. It is the body’s physiological mechanism for energy regulation, separate from emotional or habitual eating urges.

Fung argues that hormonal imbalance, primarily of insulin, drives weight gain rather than caloric excess alone. High levels of hormones like insulin raise the set point of the body’s “fat thermostat,” causing the body to store more fat. Because different foods elicit different hormonal responses, this framework holds that some foods are inherently more fattening than others regardless of calorie count.

The author’s term for refined carbohydrates consumed without accompanying protein or fat. Eating “naked” carbs such as bread with jam or breakfast cereal with skim milk causes a rapid spike in blood glucose and insulin. To avoid this, the author recommends always “dressing” carbohydrates by eating them with fats and proteins, which slows digestion and blunts the hormonal response.

A framework that categorizes foods into four groups based on their degree of industrial processing, from unprocessed (Group 1) to ultra-processed (Group 4). The author uses this system to show that ultra-processed foods trigger the hormonal responses most strongly associated with fat storage. This classification prioritizes the extent of processing as the key determinant of a food’s health impact.

This term describes the process where corporations or other powerful actors influence scientific research to produce findings that support their commercial interests. The author cites examples from the tobacco and sugar industries to show how this tactic is used to legitimize unhealthy, ultra-processed products. This process allows harmful products to be marketed as safe or even healthy.

Industrial food formulations (NOVA Group 4) made mostly from cheap, modified ingredients and additives, containing little to no whole food. The author identifies UPFs as a primary cause of obesity because they are engineered to be hyper-palatable, low in satiety, rapidly absorbed, and often addictive. Avoiding UPFs is the first of the author’s three Golden Rules for weight loss.