Fecal microbiota transplant (FMT), or stool transplant, is the administration of a fecal matter solution from a healthy donor into a recipient’s intestinal tract to directly normalize the recipient’s microbial composition and confer a health benefit (Wang et al., 2019; Gupta et al., 2015). For example, it is used in humans to control and treat recurrent Clostridium difficile infections and Pseudomembranous colitis (Park & Seo, 2021),.

Fermentation is a metabolic process where microorganisms, such as bacteria, break down complex carbohydrates in the digestive system, producing various byproducts, including short-chain fatty acids (SCFAs) and gases like carbon dioxide and methane. This process is conducted without oxygen and is crucial to digestion and gut health.

Fermented foods refer to foods and beverages that are produced as a result of the biochemical conversion of non-digestible carbohydrates (NDCs) by gut microbiota to produce the energy for bacterial growth, gasses (like carbon dioxide and methane), and organic acids (like SCFAs) under anaerobic conditions (i.e., absence of oxygen) (Alexander et al., 2019; Dimidi et al., 2019).

The “fight or flight” response is a physiological reaction that prepares the body to confront a threat (fight) or escape from it (flight). It is triggered by the sympathetic nervous system (SNS), leading to increased heart rate, heightened alertness, and redirection of blood flow to muscles, all of which enhance the individual’s ability to respond to a perceived danger.

Fight-Flight-or-Freeze System or FFFS is one of the three systems regulating human behavior proposed by Gray’s reinforcement sensitivity theory. The functioning of the FFFS determines how prone a person is to experiencing fear. Strong activity in this system makes a person more likely to excessively avoid feared objects and develop conditions such as phobias and panic.

Food addiction refers to a condition where individuals exhibit compulsive behaviors, cravings, and loss of control around food consumption, similar to patterns observed in substance addiction. It involves a complex interplay of psychological, physiological, and behavioral factors, often leading to an unhealthy relationship with food.

Food affordability refers to the extent to which individuals or households can financially afford to purchase an adequate and nutritious diet within their budget constraints. It focuses specifically on whether people have enough income or resources to buy the food they need for a healthy diet.

A conditioned response to food is frequently accompanied by increased salivation, physiological arousal, and neural activity in brain regions such as the ventral striatum (VS). This response is conditioned through environmental (smell, sight of foods), interoceptive (stress, negative affect, hormones), and physiological cues that accompany the thought of or ingestion of food (Boswell & Kober, 2016).

Food cues refer to various sensory stimuli or environmental signals that influence an individual’s perception, desire, and food consumption. These cues can include visual, olfactory, gustatory, and even auditory signals associated with food. Examples of food cues include the sight of appetizing dishes, the aroma of cooking, the taste of certain flavors, or even hearing the sizzle of food being prepared.

Food culture refers to the way food is grown, prepared, shared, and consumed, along with the customs that influence these activities.