Should people with prediabetes avoid fruit? The viral "fruit is not your friend" claim checked against current evidence

Claim 2: A medium banana has as many carbohydrates as a cup of Coca-Cola so it is "poison" for those with diabetes

Fact-check: This claim is misleading because it relies on a narrow comparison of total carbohydrate content while ignoring important differences in nutritional value and health effects.

In the video, Dr. Foran explains how the amount of carbohydrates in a banana are the same as the carbohydrates found in a cup of coco-cola. While true that a medium banana and a cup of Coca-Cola contain similar carbohydrates, this comparison lacks the importance of context.

Both bananas and Coco-Cola contain around 27g of carbohydrates but that is where the comparison ends. A medium banana not only has 27g of carbohydrates, but also 3g of fibre and a range of beneficial vitamins and minerals such as vitamin C and potassium. In comparison Coca-Cola has no fibre, negligible micronutrients and it is made almost entirely of free sugars. 

High intakes of Coca-Cola and other foods high in free-sugars have been strongly linked to obesity, type 2 diabetes and cardiovascular disease. Comparing the two as if they are equivalent oversimplifies how different foods affect blood sugar and long-term health and is an example of false equivalence. 

In addition, foods with similar carbohydrate content can affect blood glucose differently. The fibre and structure of whole fruit slow digestion and absorption, leading to a more gradual rise in blood sugar. In contrast, sugary drinks are rapidly absorbed and tend to cause sharper spikes in blood glucose. Individual responses can also vary, meaning two people may respond differently to the same food which is why nutrition advice may vary between individuals.

For individuals with diabetes it is generally recommended to cut down on high-sugar, low-nutrient foods and drinks, rather than focusing on restricting whole fruits or vegetables. These less nutritious foods can still be consumed occasionally but should not form a large part of the diet. 

Claim 3: Fruit is high in fructose which is metabolised in the liver and converted to fat

Fact-check: This claim is misleading as it oversimplifies fructose metabolism by ignoring dose,  absorption rates, and  evidence consistently showing that moderate intake of whole fruit does not promote fatty liver or negatively impact prediabetes or diabetes management.

Dr.Foran is correct that the primary sugar in fruit is fructose, and that fructose is largely metabolised in the liver. This process occurs relatively quickly, allowing fructose to be used for immediate energy or stored as glycogen.

However, fructose is not directly converted into fat under normal dietary conditions unlike what is implied in this video. Most fructose is used for energy or replenishes liver glycogen stores. Only when fructose intake is excessive particularly from concentrated sources like sugar-sweetened beverages (which deliver large amounts of rapidly absorbed sugars without fibre) does the liver significantly increase de novo lipogenesis, the process of converting excess substrates into fat (triglycerides). In typical diets, it is difficult to consume fructose from whole fruit at a level high enough to drive these harmful effects.

Importantly, whole fruit also contains fibre, water, and other nutrients that slow absorption and naturally limit intake, making it far less likely to contribute to fat production compared to high-sugar drinks. 

This distinction is also seen when comparing whole fruit with fruit juices. When fibre is removed or broken down, sugars become more readily absorbed, behaving like free sugars and potentially having different metabolic effects.

Additionally, this meta-analysis also shows that whole fruit intake is not likely to be associated with increased liver fat or metabolic dysfunction-associated steatotic liver disease (previously known as non-alcoholic fatty liver disease) in both lean and obese adults. Therefore, the claim that fruit inherently promotes fat formation in the liver is not supported by current scientific evidence.

Final take-away and conclusion

All fruits, including tropical fruits, can be included in moderate portions for those who have pre-diabetes and type 2 diabetes. Rather than solely focusing on avoiding specific fruits, it is more helpful to focus on portion sizes, variety, and making other dietary improvements such as reducing the intake of foods which are high in free sugars. 

While whole fruit does contain natural sugars, it also provides fibre, vitamins and minerals which benefit overall health. More concentrated forms such as fruit juices and dried fruit may have a greater impact on blood glucose and therefore should be consumed in smaller amounts. 

For those managing prediabetes or type 2 diabetes, practical strategies can help support blood glucose control without avoiding fruit altogether. These include keeping portions moderate, spreading fruit intake across the day rather than eating large amounts at once, and pairing fruit with foods that contain protein or healthy fats (such as yogurt, nuts, or seeds) to help slow the rise in blood sugar.

However, individual responses to carbohydrates can always vary, so personalised advice from a healthcare professional, such as a dietitian may be necessary in some cases. Overall dietary pattern, physical activity, sleep, and medication (where relevant) all play important roles in blood glucose management.

Be wary of advice to completely cut out certain foods or using extreme terms like “poison.” Nutrition is rarely that simple, and balanced, evidence-based guidance is more reliable.

When contacted for comment about this fact‑check, Dr Foran replied that “tropical fruit for the vast majority of adults living with metabolic dysfunction exacerbates their fatty liver and insulin resistance” and referred to the work of UK GP Dr David Unwin to support this view, however they did not provide any direct sources to support these claims nor did they acknowledge the other claims in the video.

Dr Unwin’s own low‑carbohydrate resources do recommend extra caution with tropical fruits, but they still allow whole fruit in moderation and do not describe fruit as “poison,” which is a much stronger and more absolute position than his. Dr Unwin’s published work is framed primarily around drug‑free remission of type 2 diabetes (and large HbA1c improvements), rather than routine day‑to‑day management in all people living long‑term with diabetes. Dr. Unwin et al.’s 2023 service evaluation explicitly describes a “primary care‑based method to achieve remission of T2D” using a low‑carbohydrate approach, with emphasis on higher remission rates when treatment is started early after diagnosis.

Dr Unwin’s work also encourages people to “eat lots of green vegetables” and advises that processed meats such as bacon, ham, sausages and salami are “not as healthy” and should only be eaten in moderation, which contrasts with Dr Foran’s dietary approach and claims that bacon is a health food. This is not directly relevant to the question of fruit and diabetes, but it does illustrate how selectively invoking Dr. Unwin’s work to support some claims while leaving out parts that contradict others is an example of cherry‑picking. This also reflects a wider issue with nutrition advice given on social media: broad, simplified messages are often not representative of the full balance of evidence but may still influence how individuals manage health issues. 

Disclaimer

This fact-check is intended to provide information based on available scientific evidence. It should not be considered as medical advice. For personalised health guidance, consult with a qualified healthcare professional.