Tired, anxious, gaining weight? It could be your hormones | Dr Helen O’Neill

Hormones control almost every system in your body. They are like an orchestra playing, so when one instrument is a little off-key, it affects the whole system. If you feel tired, anxious, or are gaining weight, your hormones may be involved. In this episode, leading reproductive expert Dr Helen O’Neill explains how hormone health affects fertility, metabolism, and mental health for both men and women.  The core question is simple: if hormones run your body, how much influence do you have over them?  Alongside ZOE’s head nutritionist, Dr Federica Amati, Helen explores the links between hormones and fatigue, anxiety, weight gain, fertility, and metabolic health. The episode covers thyroid health, chronic pain, sperm health, and why gut hormones play a central role in appetite and weight regulation. We also examine why some female-specific conditions remain misunderstood or undiagnosed, and how better data may help change that. Most importantly, this episode focuses on what you can do to take back control. With emerging science suggesting that diet plays a key role in hormone regulation, you’ll hear how fibre, plant diversity, healthy fats, and key micronutrients support gut hormone production and fertility. You’ll also learn why changes made over three months may meaningfully influence fertility, and why conception is always a shared responsibility. Help keep your hormones in tune with this guide to the relationship between gut, diet and hormones, produced in partnership with the hormone experts at Hertility. 🌱 Try our science-backed and tasty wholefood supplement Daily 30+ Get our brand-new app and Gut Health Test designed by world-leading gut health and nutrition scientists to build healthy eating habits 👉 Join ZOE Follow ZOE on Instagram. Timecodes 00:00 Intro 03:50 One hormone can change everything 09:50 Injecting testosterone can shut this down 12:30 You were born with all the eggs you’ll ever have 15:15 The subtle signs your hormones are off 17:55 The most common thyroid problem no one spots 20:30 ‘Balancing hormones’ — myth or medicine? 23:10 The condition affecting one in 10 women 25:40 Why PCOS impacts weight and mood 28:10 Why women were excluded from medical trials 30:25 The data breakthrough changing women’s health 32:30 The devastating disease that mimics cancer 35:15 It takes nine years to diagnose this 37:00 The symptom doctors often miss 39:15 Your gut is a hormone factory 41:00 As powerful as a drug? 43:00 The ‘gourmet meal’ your hormones love 44:05 The flash of zinc at fertilisation 46:15 A handful of walnuts improved sperm health 48:50 Your sperm affects your child’s future 50:30 The fertility habits that really matter 52:40 The biggest takeaway about hormones and food 📚Books by our ZOE Scientists The Food For Life Cookbook Every Body Should Know This by Dr Federica Amati Food For Life by Prof. Tim Spector Ferment by Prof. Tim Spector Free resources from ZOE The Hormone Harmony Guide: Tuning Your Body’s Internal Orchestra Eating for Better Brain Health: Your brain-gut blueprint How to eat in 2026 - Discover ZOE’s 8 nutrition principles for long-term health Live Healthier: Top 10 Tips From ZOE Science & Nutrition Gut Guide - For a Healthier Microbiome in Weeks  Better Breakfast Guide Mentioned in today's episode Hertility Health Effect of Walnuts on Male Fertility, Current Developments in Nutrition (2019) Sperm health and risk of nausea and vomiting during pregnancy, Nature (2023) Interplay of Gut Microbiota in Polycystic Ovarian Syndrome, Pharmaceuticals (2023) Have feedback or a topic you'd like us to cover? Let us know here. Episode transcripts are available here.