Carbohydrates are universal fuels for cellular energy metabolism. To reach the cells, carbohydrates in the form of monosachharides must be taken up from the external environment. The gastrointestinal tract houses the necessary processing apparatus to solve this problem. The gastrointestinal tract is a complex multiorgan system that allows the timely assimilation of ingested foods. The uptake of nutrients across the extensive absorptive membrane of the intestine requires that foods are first broken down (digested) into absorbable moieties using mechanical implements and various chemicals and enzymes. The regulation of gastrointestinal motility and secretions is orchestrated by intricate neural networks within the gut wall, long nerve reflexes, and hormones released from cells nested in the inner epithelial lining of the gut. However, the influence of the gut on glucose homeostasis is not limited to digestion and absorption. Thus while nutrients are being taken up from the intestinal lumen, gut hormones direct the switch of metabolism from the fasted condition, where stored energy substrates are being mobilized, to the fed state where absorbed nutrients are deposited for later use. We here provide an overview of the ways in which the gut influences glucose homeostasis. After a brief introduction to the concept of glucose homeostasis and the general layout of a meal, we will introduce the most common dietary carbohydrates before following their fate from ingestion to the time when they are dispersed into the circulation. This we hope will provide the reader with a robust working knowledge of the various levels of glucose regulation. This is essential when trying to understand the consequences of dietary patterns and helping patients make better dietary choices.