A gland is a group of cells whose function is to produce and secrete a specific substance (such as hormones, digestive juices, tears, saliva, and milk) either directly into the bloodstream (in the case of endocrine glands) or through a duct or other opening inside or outside the body (in the case of exocrine glands) (Maynard & Downes, 2019).

Glucagon-like peptide -1 is a hormone the gut cells produces in response to food intake. GLP-1 reduces food intake and increases insulin secretion (Gribble & Reimann, 2016).

Glycans are sugar molecules with proteins and lipids in their chemical structure.

The Glycemic Index (GI) is a scale that measures how quickly a carbohydrate-containing food raises blood glucose levels compared to a reference food, reflecting its impact on post-meal blood sugar response.

Glycoproteins are molecules composed of carbohydrates and proteins. Mucin, for example, is a type of glycoprotein that gives the mucus layer a gel-like consistency.