#570: Fructose: Metabolism, Claims & Context for Risk – Scott Harding, PhD

Introduction to this Episode

Fructose has often been labeled a uniquely damaging nutrient, blamed for obesity, diabetes, and other metabolic diseases. But does fructose truly have unique harmful effects or are the risks associated with it related to context and quantity?

The episode explores how fructose is metabolized in the body, why it gained a reputation for being problematic, and what the scientific evidence says about fructose in our diets. You will gain insight into why fructose was singled out in the past (e.g., its unique pathway in the liver and lack of insulin response), and how newer studies put those concerns into context.

It covers important nuances for practitioners and health-conscious individuals, especially given public confusion and fear around fructose (even in fruit).

About the Guest

Dr. Scott Harding, Ph.D., is an Associate Professor of Nutritional Biochemistry in the Department of Biochemistry at Memorial University of Newfoundland. His research explores the complex interactions between diet, metabolism, and chronic disease, with a particular emphasis on the metabolic effects of dietary sugars (especially fructose), the role of fats and phytosterols in lipid metabolism, and how public health policies like sugar taxation influence population health outcomes.

Dr. Harding utilizes a variety of research methodologies, including clinical trials, animal models, stable isotope tracers, and mass spectrometry techniques to elucidate nutrient metabolism pathways and their impact on cardiometabolic health.

Throughout his career, Dr. Harding has published extensively in leading scientific journals, significantly contributing to the understanding of dietary impacts on metabolic risk factors such as insulin resistance, liver fat deposition, and cardiovascular disease. In addition to his research and teaching roles at Memorial University, he serves as Editor-in-Chief of the journal

Applied Physiology, Nutrition and Metabolism.

Useful Terminology for this Episode

• Fructose: A simple sugar (monosaccharide) found naturally in fruits, honey, and some vegetables. It is also present in common sweeteners (e.g. table sugar and high-fructose corn syrup).
• High-Fructose Corn Syrup (HFCS): A sweetener made from corn starch that contains a mixture of fructose and glucose. Common formulations are ~55% fructose and 45% glucose (similar to table sugarʼs composition).
• Postprandial: The period after eating a meal. “Postprandial metabolism” refers to all the processes that digest food and handle nutrients in the hours after a meal. For example, blood sugar and blood fat levels rise postprandially as the body absorbs nutrients, and hormones (like insulin) are released to manage this influx.
• Insulin Resistance: A state in which the bodyʼs cells become less responsive to insulin. When insulin resistance is present, higher levels of insulin are required to control blood sugar.
• Hypercaloric (Diet): A diet that provides more calories than a person burns, leading to an excess calorie intake. A hypercaloric condition (caloric surplus) often results in weight gain as excess energy is stored (e.g. as body fat). In contrast, a eucaloric diet provides roughly the same amount of calories as expended (maintenance level).
• Food Matrix: The complex physical and nutritional composition of a food, including its nutrients and how they are structured within the food. The food matrix concept recognizes that we eat whole foods (with fiber, water, protein, etc.), not isolated nutrients – and this context can affect digestion and metabolic responses.