There is a lot of controversy regarding fructose and fruit consumption. Do we cut back our fruits? Do we limit it for our children? Isn’t it healthy? Shouldn’t we eat up to 5 pieces a day?
Fructose (fruit sugar) is found in fruit and vegetables and added to foods as added sugar, high fructose corn syrup (HFCS), honey, and agave. Table sugar contains 50% glucose and 50% fructose, honey 38% fructose, agave 90% fructose. Fructose is metabolised 100% by the liver, compared to glucose where only 20% is metabolised by the liver.
When you consume glucose, it is used as energy by your body, when you consume fructose it is metabolised by the liver into free fatty acids, LDL and triglycerides, all of whom are stored as fat. It is the triglycerides that are the cause of heart disease. These fatty droplets accumulate in the liver and cause visceral fat (tummy fat or pot belly). The metabolism of fructose also causes a rise in uric acid levels which can cause raised blood pressure and gout (arthritis).
Visceral (tummy) fat is the dangerous fat (remember apple shape is more dangerous than pear shape). It surrounds your organs and causes insulin resistance and eventually non-alcoholic fatty liver disease (NAFLD). Insulin resistance eventually continues to develop into Type 2 Diabetes and metabolic syndrome.
Fructose does not affect the appetite control system. It does not stop ghrelin (hunger hormone) or release leptin (satiety hormone) so you will continue to feel hungry and not full.
When fructose is consumed in whole fruit, the whole fruit also contains water, fibre, antioxidants, and nutrients so our body can tolerate it quite well. The fibre allows the sugars to be absorbed slower. The problem however, is the amount of fruit we consume (3-5 pieces a day), many fruits have been selected and cultivated to be sweeter versions of the old varieties, and the addition of sugars (50% fructose) and high fructose corn syrup in many products. Our body handles fructose the same no matter where it comes from – fruit, honey, agave, high fructose corn syrup, table sugar.
High consumption of fructose causes –
- the liver to synthesise fatty acids, VLDL, triglycerides, leading to heart disease
- increased uric acid leading to high blood pressure and gout visceral fat (belly fat) leading to fatty liver, type 2 diabetes and NAFLD
- low appetite signal control causing increased hunger
Whole fruit should be eaten, as it is such a good source of nutrients, antioxidants, water and fibre. Just be mindful of how much you are eating and what type of fruit you are eating. Try and choose the low carb, nutrient dense fruits such as berries.
Avoid ALL fruit juices as you can costume 3-4 times the amount of fruit in one glass than you could possibly eat as whole fruit. Most fruit juices have added sugars and have fortified with nutrients because almost no vitamins are left once it has been juiced, processed and preservatives added to extend its life for sale in the supermarket.
Limit the high sugar fruits such as pineapple, mango, melon, dates, and dried fruit (incredibly high in sugar, no water, quickly absorbed, can consume far more dried fruits than whole fruits).
Go for high nutrient dense fruits such as berries.