Why Some Diets Don't Work: The Science of Appetite | Ep. 7 (ft. Dr. Harriët Schellekens)

Why do diets fail? Why are you always hungry? And what if the secret to managing your weight isn't about eating less, but eating better? In this episode of Straight Talking Science, Barry Skillington sits down with Dr. Harriët Schellekens, senior lecturer in the Department of Anatomy and Neuroscience at UCC, funded investigator for APC Microbiome Ireland and Food for Health Ireland, and leading expert on appetite hormones and the gut brain axis. Harriët unpacks the science behind hunger, cravings, and why your body fights back when you crash diet. From GLP-1 drugs like Ozempic to ghrelin, the hunger hormone, to the hidden role of your gut microbiome in driving food choices, this conversation reveals why appetite isn't just about willpower. It's biology. Your gut hormones, your stress levels, your sleep, and the trillions of microbes living inside you are all constantly communicating with your brain, influencing what you eat, how much you eat, and whether you can stop. Topics covered: Dr. Harriët Schellekens' research on appetite hormones and the gut brain axis What GLP-1 drugs are, how they work, and who should actually be taking them Why obesity is a disease, not a lifestyle problem The biology of appetite: hormones versus willpower Ghrelin: the hunger hormone that drives food intake and why it matters How ghrelin dysregulation contributes to obesity and emotional eating The problem with ultra processed foods and the pre digestive versus post digestive mismatch Why high fat high sugar combinations trick your brain and drive overeating Sugar substitutes: the good, the bad, and the science behind natural sweeteners like allulose The gut microbiome's role in weight, appetite, and food cravings How your microbes can harvest more calories from food and influence obesity risk Microbiome diversity across life stages: from infancy to aging How gut bacteria signal to your brain to modulate food motivation and preferences Stress, cortisol, and emotional eating: the hormonal connection Why crash diets fail: the hormone perspective and what happens when you restrict calories Practical food strategies: fixing the mismatch between taste and nutrition Early life programming: how childhood diet shapes eating behavior and obesity risk later in life Probiotics, prebiotics, and targeted microbial interventions for appetite regulation Parenting and food: teaching kids healthy habits without guilt or fear Key takeaways: eat better, not less, and why lifestyle changes beat quick fixes The bottom line? Diets don't work because they fight your biology. When you restrict calories, your body responds by increasing ghrelin, raising cortisol, and making you crave the exact foods you're trying to avoid. Ultra processed foods create a mismatch between what your mouth tastes and what your gut actually receives, driving overeating and dysregulating your appetite hormones. Your gut microbiome plays a massive role in how much energy you extract from food, what foods you crave, and how your body responds to stress. The solution isn't eating less. It's eating better. Whole foods, fiber, protein, and slow release carbohydrates that match the promise of calories with actual nutritional delivery. Feed your microbes, balance your hormones, prioritize sleep, manage stress, and stop crash dieting. Your body is designed to work with you, not against you. Give it the right signals, and it will respond. Website: https://atlantiaclinicaltrials.com/ LinkedIn: https://ie.linkedin.com/company/atlantia-clinical-trials Instagram: https://www.instagram.com/atlantia_clinicaltrials/ Facebook: https://www.facebook.com/AtlantiaClinicalTrials/ Listen to Straight Talking Science on Spotify: https://open.spotify.com/show/5vdjz93jVdKlY0Arl6rQ7Z #Appetite #WeightManagement #GLP1 #Ghrelin #GutMicrobiome #AppetiteHormones #Obesity #EmotionalEating #UltraProcessedFoods #HealthyEating #SciencePodcast #GutBrainAxis