Thanks to Catarina Soares, Medical student at Nottingham University, for putting this piece together. Head to the bottom of the page to read a little more about Catarina!
Diet-related myths on the internet are not hard to come by, and this particular one can be quite persistent. I’ll jump right in and say no – fruit is not bad for you.
Fruit has many proven benefits. People who eat more fruit, particularly citrus fruits, have a lower risk of having a stroke (1), and increased consumption of fruit is actually linked to a decrease in mortality due to cardiovascular disease (2) – although researchers don’t really understand why. They think it could be because the vitamins in fruit lower blood pressure or help prevent blood clots from forming (1,3), but there isn’t enough research on this topic to know for sure.
An alternative explanation may be the link between fruit and another big risk factor for cardiovascular disease: type 2 diabetes. Eating more fruit, particularly apples and blueberries, can decrease the risk of developing diabetes (4). However, it’s important to distinguish between fruit juice and whole fruits: increased consumption of fruit juice actually increases the risk of diabetes. This may be because when we put fruit through a blender, we lose some of its nutritional value and break down the fibre in it, meaning we decrease the time it takes to be digested. The sugar goes into our bloodstream in a faster, less controlled way, and we have more of it before feeling full or satisfied, often without realising (4,5).
So where does the idea that fruit is bad for you come from?
Most articles online focus on the sugar content: fruit is rich in a naturally occurring sugar called fructose. It’s true that fruit has a higher sugar content compared to vegetables, and excess fructose may have some negative effects on our body, just like any kind of sugar. It can increase fat deposits in the liver and reduce our ability to respond to insulin (6,7), and scientists think it also affects the hormones that tell our brains that we’re full, making us eat more than we need (8,9). That being said, you’d need to eat a lot of fruit for this to happen. The studies looking into the harmful effects of fructose are mostly focussed on excess consumption, which can result from eating lots of processed, sweetened foods, with very high levels of sugar – much higher than in fruit (7).
You get a lot more than just sugar when you eat a piece of fruit. Why? Because fruit is also full of water, fibre and nutrients. A small apple has the same amount of calories as a tablespoon of white sugar, which is about 50 calories. However, the apple has 10 grams of sugar, 2.4 grams of fibre and some minerals and vitamins, like potassium, sodium and vitamin C; while the spoonful of sugar has just 12.6 grams of sugar (USDA). Eating an apple requires you to take bites and chew it, which slows down your digestion and absorption of the sugar, keeping it from hitting your liver all at once (2,5). This is why you feel satisfied after eating a piece of fruit, but wouldn’t if you had a tablespoon of sugar, although they may have the same amount of calories.
This doesn’t mean you can eat unlimited fruit – you can have too much of a good thing. Sugar is still sugar, and it’s important to stay within the recommended amount per day. This is particularly important if you have diabetes, as your body struggles to control your blood sugar. This is where the GI, or glycaemic index, can come in to help you, especially if you have type 2 diabetes. The GI tells you how fast your blood sugar rises after eating something, with a low GI indicating a slow rise – lower GI foods help control type 2 diabetes better (10). Looking at the GI of different fruits can help you keep on top of your blood sugar levels, but most types of fruit are low GI anyway.
Fruit is not bad for you – it’s great! Aim for at least 5 a day of fruit and veg, and try to have whole fruits instead of juices. Just keep in mind, as with everything in life, that moderation is key. Enjoy Nature’s dessert!
- Mizrahi A, Knekt P, Montonen J, Laaksonen MA, Heliövaara M, Järvinen R. Plant foods and the risk of cerebrovascular diseases: a potential protection of fruit consumption. Br J Nutr [Internet]. 2009 Oct 31 [cited 2018 Mar 24];102(7):1075. Available from: http://www.journals.cambridge.org/abstract_S0007114509359097
- Wang X, Ouyang Y, Liu J, Zhu M, Zhao G, Bao W, et al. Fruit and vegetable consumption and mortality from all causes, cardiovascular disease, and cancer: systematic review and dose-response meta-analysis of prospective cohort studies. BMJ [Internet]. 2014 Jul 29 [cited 2018 Mar 25];349:g4490. Available from: http://www.ncbi.nlm.nih.gov/pubmed/25073782
- Chong MF-F, Macdonald R, Lovegrove JA. Fruit polyphenols and CVD risk: a review of human intervention studies. 2018 [cited 2018 Mar 24]; Available from: https://www.cambridge.org/core/services/aop-cambridge-core/content/view/E868333FE2334F56181BC9C9F1B20FD8/S0007114510003922a.pdf/fruit_polyphenols_and_cvd_risk_a_review_of_human_intervention_studies.pdf
- Muraki I, Imamura F, Manson JE, Hu FB, Willett WC, van Dam RM, et al. Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies. BMJ [Internet]. 2013 Aug 28 [cited 2018 Mar 25];347:f5001. Available from: http://www.ncbi.nlm.nih.gov/pubmed/23990623
- Flood-Obbagy JE, Rolls BJ. The effect of fruit in different forms on energy intake and satiety at a meal. Appetite [Internet]. 2009 Apr [cited 2018 Mar 25];52(2):416–22. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19110020
- Lê K-A, Ith M, Kreis R, Faeh D, Bortolotti M, Tran C, et al. Fructose overconsumption causes dyslipidemia and ectopic lipid deposition in healthy subjects with and without a family history of type 2 diabetes. Am J Clin Nutr [Internet]. 2009 Jun 1 [cited 2018 Mar 25];89(6):1760–5. Available from: https://academic.oup.com/ajcn/article/89/6/1760/4596803
- Ouyang X, Cirillo P, Sautin Y, McCall S, Bruchette JL, Diehl AM, et al. Fructose consumption as a risk factor for non-alcoholic fatty liver disease. J Hepatol [Internet]. 2008 Jun 1 [cited 2018 Mar 25];48(6):993–9. Available from: https://www.sciencedirect.com/science/article/pii/S0168827808001645
- Shapiro A, Mu W, Roncal C, Cheng K-Y, Johnson RJ, Scarpace PJ. Fructose-induced leptin resistance exacerbates weight gain in response to subsequent high-fat feeding. Am J Physiol Integr Comp Physiol [Internet]. 2008 Nov [cited 2018 Mar 25];295(5):R1370–5. Available from: http://www.physiology.org/doi/10.1152/ajpregu.00195.2008
- Page KA, Chan O, Arora J, Belfort-DeAguiar R, Dzuira J, Roehmholdt B, et al. Effects of Fructose vs Glucose on Regional Cerebral Blood Flow in Brain Regions Involved With Appetite and Reward Pathways. JAMA [Internet]. 2013 Jan 2 [cited 2018 Mar 25];309(1):63. Available from: http://jama.jamanetwork.com/article.aspxdoi=10.1001/jama.2012.116975
- Glycaemic index and diabetes | Diabetes UK [Internet]. [cited 2018 Mar 25]. Available from: https://www.diabetes.org.uk/guide-to-diabetes/enjoy-food/carbohydrates-and-diabetes/glycaemic-index-and-diabetes