#583: Ultra-Processed Foods & Fixing the Food Environment – Kevin Hall, PhD

Introduction to this Episode

Ultra-processed foods have become central to the way we eat and to many of the challenges we face in public health nutrition. They dominate supermarket shelves, shape population diets, and often appear as the prime suspect in rising obesity and metabolic disease rates. But beyond the label itself, what exactly makes these foods problematic? Is it their nutrient composition, their texture and palatability, the rate at which we consume them, or the broader environments that make them so accessible and appealing?

The debate around ultra-processed foods sits at the intersection of metabolic science, behaviour, and policy. It raises uncomfortable questions about how food systems evolved to prioritise convenience and profit, and what it might take to meaningfully change that trajectory.

In this episode, Dr. Kevin Hall joins the podcast to examine the evidence from controlled feeding studies and population research, exploring what we really know about ultra-processed foods, overeating, and how we might begin to fix the food environment.

About The Guest

Dr. Kevin Hall, PhD, is an internationally renowned expert in human nutrition, metabolism, obesity, and neuroscience. Dr. Hall has made groundbreaking discoveries about how our environment shapes dietary behaviors, and how nutrition and physical activity affect human metabolism and body weight regulation.

Having previously worked at the National Institutes for Health (NIH) for over two decades, Dr. Hall led transdisciplinary research that combined tightly controlled metabolic ward trials, advanced neuroimaging, and mathematical modeling to generate mechanistic insights into the drivers of obesity and diet-related chronic diseases.

Useful Terminology for this Episode

• Ultra-Processed Foods (UPFs): Formulations of ingredients, mostly for industrial use, that result from a series of industrial processes and typically contain little or no intact whole food. They include cosmetic additives (e.g. colorings, flavorings, emulsifiers, sweeteners) and are designed to be hyper-palatable, convenient, shelf-stable, and profitable. UPFs are classified as Group 4 in the NOVA system, and are distinct from merely “processed” or “processed culinary” foods.
• NOVA Classification: A system that categorizes foods by degree of processing. NOVA defines Group 4 (Ultra-Processed Foods) as products containing substances and additives rarely found in home kitchens. NOVA is widely used in research on diet and health, though some criticize it for grouping very different foods together under “ultra-processed.”
• Energy Density: The amount of calories per gram of food (kcal/g). High energy density foods provide a lot of calories in a small weight or volume, whereas low energy density foods have fewer calories per gram.
• Hyper-Palatable Foods: A term used to describe foods engineered or composed to maximize appeal, often by combining high levels of fat, sugar, salt, and/or refined carbohydrates. There has been a lack of a universal definition for this term in research.
• Nutrient Profiling System: A method to evaluate food healthfulness based on its nutrient content. Examples include the UKʼs nutrient profiling model and the Healthy Eating Index (HEI) used in the U.S. They score foods or entire diets on components like fruits/vegetables, whole grains, sodium, sugar, etc.
• Food Environment: The collective physical, economic, and social factors that influence peopleʼs food choices and nutritional status. It includes the availability, affordability, marketing, and placement of foods in places like supermarkets, restaurants, schools, and workplaces.