The Relationship between IBS and Sugar When looking for dietary solutions for irritable bowel syndrome (IBS), some people choose to cut out foods like gluten, dairy and soy. However, one major irritant that they overlook is sugar. So, how are and IBS and sugar connected? Many people do not realize the impact that sugar has on the digestive system. Overeating sugar can lead to cramping and diarrhea. Plus, some people with IBS may also have a sugar intolerance. The digestion of sugar starts in the mouth and continues through the digestive system to the small intestine. Digestive enzymes split disaccharides, a combination of two simple sugars, apart. Once they have been separated, the small intestine absorbs the sugars. They then pass through into the bloodstream to be metabolized and used for energy and are also sent to the liver for further processing. What Happens When We Eat Too Much Sugar? While sugar is an important form of energy, too much of it can have negative effects on the body. Too much sugar in your bloodstream can cause thirst, nausea, dizziness and headaches. High blood sugar also stimulates your appetite and may cause you to overeat, leading to weight gain. The body also stores excess sugar as fat to be used as a future energy source. Consuming too much sugar can lead to inflammation. This can cause joint pain, as well as speed up the aging of your skin. It can also cause problems with your heart, liver, kidneys and pancreas. Eating excess amounts of sugar can be addictive, as it causes the brain to release dopamine. However, the brain will need an increasing amount of sugar to have the same effect over time. In addition to the other problems caused by overeating sugar, the digestive system can be affected as well. When we have overeaten sugar, the small intestine cannot absorb all of it and pass it into the bloodstream. Instead, the excess sugar travels to the large intestine.