At the most basic level, sugar (along with the other foods you eat) is broken down by the body to use for various complex cellular functions. This process of digestion and metabolism fuels your brain, muscles, heart, and every other organ and body system. The foods you consume directly impact your body’s abilities, starting with their initial breakdown during digestion.
Digestion Starts in the Mouth
When most people think of digestion, the stomach is what comes to mind. It is often overlooked that digestion actually begins in the mouth. Chewing physically breaks down the foods that are about to be introduced to the rest of the digestive tract, and the salivary glands in the mouth release enzymes like amylase that begin the chemical breakdown and absorption of nutrients.
Sugars are the most easily absorbed at this stage, so blood sugar can be impacted before you even swallow your food. As the amount of glucose (sugar) in the blood elevates, the pancreas is stimulated to release insulin, which promotes the uptake of that glucose from the blood into the cells. This both ensures that glucose (rather than stored fat) is used as the primary energy source and triggers extra glucose to be stored as muscular glycogen or fat tissue.
Not All Sugars Are the Same
There are many different kinds of sugar, and their chemical makeups mean they are broken down differently. Generally, sugars are categorized as monosaccharides, disaccharides, and polysaccharides based on the number of building blocks that need to be broken down to be metabolized. The sugar found in fruit (fructose, a monosaccharide) is processed differently from the carbohydrates found in lentils (starch, a polysaccharide).
The Digestion Process
At the cellular level, your body uses glucose and oxygen to perform its many amazing functions. All sugars and other carbs need to be broken down into easily-used monosaccharides.
After you swallow, sugar and other foods travel down the esophagus via peristalsis into the stomach and then the small intestines. Here, sugars are all broken down by additional enzymes into single units and absorbed for further use.
How Sugar Is Different
Digestion isn’t a one size fits all process. There are several factors that play roles in how sugar is digested by the body, including other nutrients eaten in conjunction with the sugar, the glycemic index/load of the meal, fiber consumption, acidity of the food, and your individual health and physiology.
The way your body breaks down simple sugars (like white sugar) is different from the way fats, proteins, and even complex carbohydrates are broken down. For example, the fats you eat are emulsified by bile salts, their bonds are broken down by pancreatic lipases, and the resulting fatty acids are used for tissue development, energy availability, and conversion into other cellular building blocks. So while, on your end, it seems like you simply chew up, swallow, and then digest all the food you eat in one straightforward process, the individual nutrients are actually broken down and utilized quite differently.
While your body is a beautiful, efficient machine that can break down and use nutrients from a variety of sources, not all sources are equally as good. Sugars can cause various problems in your body, beginning as soon as you put them into your mouth and trigger the digestive process and blood sugar increase. Sugar digestion interrupts important body functions by triggering various responses in those body systems, and cutting back on sugar allows your body to run more efficiently.