We know that excess fructose can cause a bunch of negative effects on the body. Almost everywhere I look, studies are showing effects from high fructose sources like table sugar, HFCS, and fruit juices. If a healthy person who doesn’t suffer from fructose intolerance were to eat large amounts of fruits but limit all other fructose sources, would it still cause the same detrimental effects? There is conflicting info online. Most say that large amounts of fruit is bad, others say eating large amounts of fruits will not cause any bad effects because the fiber slows down digestion. It doesn’t make sense to me since the body still has to deal with a large amount of fructose while digesting the fruit. Anybody familiar with fructolysis?
How many servings of fruit are we talking? For example, if it’s 15 servings of fruit/day then I would say it could possibly cause deleterious effects to health, though likely through those linked to weight gain (e.g. 10 bananas = an extra 900-1000kcal). I don’t think there are many situations where 5-10 servings of fruit will have negative effects on health.
Generally speaking, I believe the evidence showing the detrimental effects of fructose on human health real-world settings are in the context of HFCS, and it is highly likely that this association is due to the excessive amount of calories that are usually consumed in these situations, that is, I can’t see much evidence showing that HFCS independently leads to poor health outcomes. Though I know that this area is quite controversial and some nutrition scientists believe HFCS is inherently bad (though I’m personally not convinced due to the weakish evidence to support these claims, such as mechanistic studies rather than robust clinical evidence). There is plenty of evidence showing that fruit is good for us, generally speaking, due to the package of nutrients (fibre, vitamins, minerals, phytonutrients etc), even though it contains fructose. I don’t think there are any legitimate nutrition scientists out there (I mean the ones that have dedicated their lives to researching the science at reputable universities, not the self-proclaimed ones you see on instagram) who would say fruit is bad for you because of the fructose it contains. In saying this, it is important to remember that this is a generalisation and there will be situations where it would be possible to eat too much fruit but I’d say these situations are the exception not the rule (e.g. poor BGL control in diabetes). This is my take but I would be interested to hear others’ views.
Hi everyone,
Glucose and Fructose has 2 different metabolic pathways. About 80-90% of fructose you consume will be metabolized in the liver. This process is highly unregulated, in comparison to glucose, which has several rate-limiting steps that regulate the amount of glucose your cells use.
If you consume solely fructose (fruit or high fructose corn syrup), you will eventually have so much unregulated energy being produced in your liver cells that they will convert to fat for storage. Hence, non-alcoholic fatty liver disease.
Hope this answers your questions! Linking a study below that explains more.