#476: Fructose in Perspective – Dietary Villain or Misunderstood Nutrient?

In Podcasts by Danny Lennon5 Comments


Fructose is a type of sugar that is commonly found in fruits, vegetables, and many processed foods. In recent years, there has been a lot of discussion and debate about the impact of fructose on health, with some claiming that it is a major contributor to obesity, diabetes, and other chronic diseases. However, these claims are often at odds with what the scientific literature actually says.

One of the most common claims about fructose is that it is inherently “bad” for health, and that consuming too much of it can lead to a wide range of health problems. This idea has been popularized in many popular diet and health books, and has led to a widespread fear of fructose among the general public. However, many of these claims are based on outdated or oversimplified research, and do not reflect the complex reality of how fructose interacts with the human body.

Another common claim about fructose is that it is uniquely responsible for the current obesity epidemic, and that reducing fructose intake is the key to weight loss and better health. While it is true that excessive consumption of sugary foods and beverages can contribute to weight gain and other health problems, the idea that fructose is uniquely responsible for these issues is not supported by the scientific evidence. In fact, many studies have found that total sugar intake, rather than fructose specifically, is the most important factor in the development of obesity and related health problems.

In this episode we discuss the unique aspects of fructose metabolism, why some studies appear to show unique harm of fructose, and the implications of this for dietary choices.

Co-hosts for this Episode

Dr. Alan Flanagan has a PhD in nutrition from the University of Surrey, where his doctoral research focused on circadian rhythms, feeding, and chrononutrition.

This work was based on human intervention trials. He also has a Masters in Nutritional Medicine from the same institution.

Dr. Flanagan is a regular co-host of Sigma Nutrition Radio. He also produces written content for Sigma Nutrition, as part of his role as Research Communication Officer.

Danny Lennon has a master’s degree (MSc.) in Nutritional Sciences from University College Cork, and he is the founder of Sigma Nutrition.

Danny is currently a member of the Advisory Board of the Sports Nutrition Association, the global regulatory body responsible for the standardisation of best practice in the sports nutrition profession.


  • Fructose, High-fructose Corn Syrup & Glucose-Fructose Syrups
  • Why is Fructose Singled Out?: Metabolism Basics
  • Liver Fat
  • Uric Acid
  • Insulin Resistance
  • Fructose Feeding Studies vs. Fructose in the Diet
  • Unique Effect of Fructose? – Substitution Analyses

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  1. Thank you for this podcast – as a type one diabetic my concerns are:
    1)how relevant is the increase in fructose when blood sugar levels (average) > 7 mmol/l lead to excess glucose being converted to fructose via the polyol pathway and
    2) common remedies that diabetics are educated to use for hypoglycaemia often contain sucrose (and fructose without rate-absorbing fibre in addition if commercial fruit juice is used). With the carbohydrate-heavy diets that for the past 40 plus years have been prescribed for diabetics ‘industrial’ doses of insulin are prescribed increasing the risk of high bsl variability and occasioning more severe and frequent hypoglycaemic episodes hence more sucrose/fructose intake and often weight gain. This weight gain is exacerbated by the n’eat what you like and dose with insulin to cover it they dietary advice which has been linked to the condition dubbed ‘double diabetes’ ( thule one diabetes plus increased insulin resistance due to diet and weight gain (and whether from increased calories or glucose or fructose – increased risk of fatty liver formation.
    3) estimates in USA and other first world counties show an increasing percentage of population with metabolic syndrome – and so the actual population with ‘normal’ caloric intake which you refer to in discussion about isocaloric studies is becoming lower. And metabolic dysfunction as aq risk factor for excessive sucrose ( ? and any form of non-fibre carbohydrate = glucose) more relevant

    1. Author

      Hi Tony,

      If I’m understanding you correctly, then I agree that much of the population likely overconsume calories. In addition, if someone with diabetes has an approach of eating lots of poor quality foods and thinking that more insulin will negate any issues, then I also agree that’s misguided.

      However, I feel that virtually all solid health & nutrition advice would recommend dietary patterns where these things are not occuring. And within the context of such food choices, then fructose doesn’t seem to be an issue. Conversely, if someone is eating in the manner you describe, then they have many issues to address, beyond just total frutose intake.

  2. Thank you for this episode. I stopped eating fruit because I was diagnosed with stage 3 liver fibrosis without steatosis. Doctor thinks that either my undiagnosed celiac disease caused the fibrosis. I was afraid to eat fruit from listening to other podcasts stating that fructose causes NAFLD and I was worried that eating fruit could lead to cirrhosis. I started eating fruit again after listening to this episode. I am glad I purchased a lifetime premium subscription to support your podcast and what you do for people like me that just want to eat healthy and feel good.

    1. Author

      Hey Lisa,

      Thanks so much for taking the time to listen and comment, and especially for supporting Sigma Nutrition through a Premium membership.

      I’m so glad to hear that discussions of the evidence are not only intellectually interesting, but are able to reduce unnecessary worries about foods.


  3. Thanks for pointing out many areas of misinformation in nutrition science. Fruits can be a nice treat but I more enjoy my whole wheat bread for some reason. Fruit can be useful in that it has lower calorie density so regularly eating it can help some individuals in weight loss or weight maintenance. For me it’s a fine line between benefit of calorie reduction and not feeling as satisfied if eating too many fruits but not quite enough calories on a given day.

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