I don’t know many people who don’t like to eat some type of fruit. Most fruits are delicious, many of them very sweet too. But is it good or bad to consume fruit?
There is actually quite a lot of discussion about this. We often hear that consuming too much sugar is not healthy, for many reasons. Table sugar, or sucrose, contains 50% fructose and 50% glucose. Fructose and glucose are both monosaccharides, but sucrose (table sugar) and fructose (fruit sugar) are metabolized differently in the body.
Cambridge dictionary describes fruit as “the soft part containing seeds that is produced by a plant.” Glucose comes from the Greek word “sweet” and our body can easily use it as energy. When it is in the bloodstream we call it blood sugar, and we need the hormone insulin to moves glucose from the blood into the body’s cells for energy and storage.
Fructose is found in mainly in fruits but also naturally in other plant foods such as honey, sugar beets and some vegetables such as asparagus. Fructose is sweeter than table sugar, which is maybe one of the reasons why we like fruit and fruit juice. Fructose metabolizes mainly in the liver and is insulin independent, which means that it does not require the hormone insulin and thus has a low impact on blood glucose levels. Some examples of high fructose fruits and vegetables are watermelon, apples, grapes, mangos, dates, figs and pears. Fructose is also present in vegetables including artichokes, asparagus, peas, zucchini, mushrooms, onions, sugar cane and also in honey. Some low fructose fruits and vegetables include blueberries, strawberries, avocado, carrots, lemons, green beans and grapefruit.
High fructose corn syrup, which is mainly found in soft drinks and ultra-processed foods, contains about 55% fructose and 45% glucose. In its liquid form, for example in soft drinks, it is absorbed very quickly especially if consumed on an empty stomach. This can lead to easy over-consumption of fructose and calories as well. Also, fructose is absorbed from the gastrointestinal (GI) tract by a different mechanism than that in which glucose is absorbed. Glucose stimulates insulin release from the pancreas but fructose does not. So high fructose consumption can induce insulin resistance and other types of metabolic syndrome and some people can not absorb the natural fructose sugar in fruits, which is the common symptom of irritable bowel syndrome (IBS). Because fructose metabolizes mainly in the liver and does not require insulin it is much more readily stored as a fat and can produce triglycerides on is own. If you consume too much fructose in your diet this can lead to obesity, type 2 diabetes, and NAFLL (non-alcoholic fatty liver disease), a condition caused by a build up of fat in the liver. Sucrose (table sugar) converts to fructose and glucose by acid hydrolysis in the stomach, and sucrase-isomaltase cleavage in the small intestine.
Whole fruits contain soluble and insoluble fibers. These two fibers together prevent the majority of the fruit’s sugar from being absorbed early on during the digestive process, which limits the rate of sugar absorption in the liver. So choosing to consume more whole food sources in your diet, and not choosing to drink fruit juice and soft drinks, can dramatically reduce the amount of fructose that you consume. You can also add some protein while consuming the fruits, such as greek yogurt. Some people report that eating fruits promote their hunger, so if you like you can add some healthy fat with your fruits such as avocados and nut butters too. For example, you could eat an apple with some almond butter.
Unfortunately our body does not give us any free passes, so do remember that everything needs balance, even the healthiest foods.
References:
Cambridge Dictionary. Fruit. https://dictionary.cambridge.org/dictionary/english/fruit#google_vignette
WebMD. What Is Glucose? https://www.webmd.com/diabetes/glucose-diabetes
National Library of Medicine. Physiology, Glucose Metabolism. https://www.ncbi.nlm.nih.gov/books/NBK560599/
National Library of Medicine. Physiology, Glucose Metabolism. https://pubmed.ncbi.nlm.nih.gov/32809434/
National Library of Medicine. Biochemistry, Fructose Metabolism. https://www.ncbi.nlm.nih.gov/books/NBK576428/
Mayo Clinic. Fructose intolerance: Which foods to avoid? https://www.mayoclinic.org/fructose-intolerance/expert-answers/faq-20058097
NoFructose. Fruit. https://www.nofructose.com/food-ideas/fruit/
Food Insight. What is Fructose? https://foodinsight.org/what-is-fructose/
