The 5 foods you’re eating every day that are more HARMFUL than sugar
Professors Sarah Berry and Tim Spector explain that while sugar itself isn't inherently evil, the problem lies in consuming rapidly-absorbed free sugars that cause blood glucose spikes and crashes, leading to inflammation, metabolic dysfunction, and increased risk of obesity, diabetes, heart disease, and dementia. The key distinction is between intrinsic sugars in whole foods (beneficial) and free/added sugars in ultra-processed foods (harmful), and the solution involves gradual dietary changes rather than elimination.
Summary
This episode of 'Starting Over' features nutritionists Professor Sarah Berry from King's College London and Professor Tim Spector, world experts on nutrition and the gut microbiome, discussing the actual science behind sugar consumption and its health impacts.
The experts clarify that sugar itself isn't the villain—humans need glucose to fuel their brains and cells, and our bodies can synthesize glucose from protein, fat, and carbohydrates even without consuming added sugar. The real problem is the type and timing of sugar consumption. When free sugars (sugars outside the natural structure of food, including added sugars, syrups, honey, and fruit juices) are consumed, they're rapidly absorbed into the bloodstream, causing sharp glucose spikes around 15-30 minutes that return to baseline in about 2 hours. This triggers an insulin overshoot that can cause glucose levels to dip below their starting point 2-4 hours later, making people feel tired and hungry and causing them to consume approximately 320 more calories per day.
Repeated high blood sugar spikes stimulate the immune system to create inflammation, which travels via the vagus nerve to the brain and has been linked to cognitive decline, Alzheimer's disease, depression, and even schizophrenia. Additionally, the combination of excess calorie consumption and inflammation from high sugar intake contributes to obesity, type 2 diabetes, heart disease, and multiple cancers—not through a direct carcinogenic effect of sugar, but through the inflammatory state and metabolic dysfunction it creates.
Critically, these health risks exist regardless of body weight. The experts explain the concept of being 'thin on the outside, fat on the inside' (visceral fat around organs), which can lead to metabolic dysfunction and disease without visible weight gain. High sugar intake can increase inflammation independently of obesity.
The experts distinguish between intrinsic sugars (found within the structure of whole foods like apples) and free sugars. Whole fruits contain fiber, polyphenols, and other bioactive compounds that slow glucose absorption, prevent blood sugar dips, and actively counteract inflammation. Fruit juice, by contrast, delivers the same sugar without the fiber and structural benefits, creating the same harmful glucose dynamics as sugary drinks. Dried fruits, while concentrated in sugar, also concentrate beneficial compounds and are unfairly demonized if consumed in moderation.
The episode identifies hidden sugar in seemingly healthy foods: flavored yogurts marketed as 'low-fat' or 'fruit' often contain substantial added sugar masked by other flavors; breakfast cereals are highly variable; and common sauces like ketchup contain surprising amounts of hidden sugar. The difference in labeling between the US (which separates free and intrinsic sugars) and the UK (which only shows total sugar) makes identification harder in some regions.
Regarding sugar alternatives, artificial sweeteners provide short-term metabolic benefits (no blood glucose spike) but maintain the sweet taste in the mouth, preventing taste bud adaptation and perpetuating cravings for sweet foods. This explains why switching to diet drinks doesn't typically lead to weight loss—people compensate by eating more other foods.
The experts reject both the narrative that all sugar is dangerous and the idea that complete elimination is necessary. Instead, they recommend gradual reduction of free sugars (allowing taste buds to adapt over time), careful label reading, and recognition that enjoyment of food matters. They provide practical strategies: eating whole fruits instead of juice, choosing plain yogurt and gradually reducing added sweetener, and being mindful of ultra-processed foods where manufacturers hide multiple types of sugar under different names to avoid labeling it as predominantly sugar.
When indulging in high-sugar foods, three strategies minimize negative effects: eating dessert within 30 minutes of a meal containing healthy fats and proteins (which reduces the glucose peak and prevents the dip); taking a 10-minute walk within 20-30 minutes of consumption (which causes muscles to utilize glucose); or even isometric leg exercises at a desk can significantly lower glucose response. Evolution prepared humans to handle episodic high sugar consumption (the example given is the Hadza tribe consuming honey for 2 days then going weeks without), but not the constant low-level sugar exposure present in modern ultra-processed foods.
About this episode
How can you enjoy sugar without gaining weight, fuelling cravings or crashing later in the day? The answer, surprisingly, is not to cut it out. In today’s episode, Professor Tim Spector and Professor Sarah Berry discuss which forms of sugar affect your blood sugar levels most, and what small changes you can make today to reduce the impact. They also explore how sharp blood sugar spikes and dips may affect hunger, energy, inflammation and long-term health. By the end of the episode, you’ll know how to spot hidden sugars, how to avoid the afternoon slump and energy crashes, and, most importantly, how to enjoy cake with less impact on your blood sugar. Sugar is not the enemy. But could a few small changes help you enjoy sweet foods without the cycle of cravings, hunger and energy crashes? 🌱 Try our science-backed and tasty wholefood supplement Daily30: https://zoe.com/daily30?utm_medium=zoe_podcast&utm_source=youtube&utm_campaign=d30 🌿Let your gut microbes snack on the ZOE Gut Health Bar | https://zoe.com/snackbar?utm_medium=zoe_podcast&utm_source=youtube&utm_campaign=GHB Build healthy habits. Download the ZOE app today and start your trial for just £2.30 for your first week. 👉 Join ZOE: https://zoe.com/buymembership?utm_medium=zoe_podcast&utm_source=youtube&utm_campaign=BAU Follow ZOE on Instagram | https://www.instagram.com/zoe/ Timecodes 00:00 Sugar isn't the problem you think it is 03:28 If fruit is full of sugar, why is it good for us? 08:30 What really happens after you drink a sugary drink? 12:46 Why sugar leaves you hungry a few hours later 16:15 The blood sugar dip that makes you eat 320 extra calories 19:19 The surprising link between sugar and inflammation 22:00 Can blood sugar affect your brain health? 25:25 What the science really says about sugar and cancer 29:25 We've been blaming sugar for the wrong things 31:45 The 2 types of sugar most people confuse 32:35 The hidden sugars lurking in everyday foods 35:32 Why energy drinks may be worse than you think 38:51 Why orange juice may not be as healthy as you think 40:10 Why fruit and fruit juice are not the same thing 43:53 Why some smoothies behave like sugary drinks 45:03 Should you quit sugar completely? 46:46 Are sweeteners helping or keeping you hooked? 49:55 Is honey actually healthier than sugar? 51:40 3 everyday foods with surprisingly high sugar 52:27 How to enjoy cake without the blood sugar crash 55:01 The 10-minute habit that lowers your glucose response 57:15 Why energy drinks may be making your slump worse 58:32 The biggest sugar traps to watch out for 📚Books by our ZOE Scientists The Food For Life Cookbook | https://amzn.to/4amfIMX Every Body Should Know This by Dr Federica Amati | https://amzn.to/4blJsLg The Appetite Reset by Dr Federica Amati | https://amzn.to/4aBakbR Food For Life by Prof. Tim Spector | https://amzn.to/4amZinu Ferment by Prof. Tim Spector | https://amzn.to/4hU1Df5 Good Mood Food (preorder) by Prof. Tim Spector | https://amzn.to/4l9oXat Free resources from ZOE: The Smart Snacking Guide: How to feed your gut, fuel your day, and snack without guilt | http://ZOE.com/snacking-2026?utm_medium=zoe_podcast&utm_source=youtube&utm_campaign=snacking Eating for Better Brain Health: Your brain-gut blueprint | https://ZOE.com/brainhealth?utm_medium=zoe_podcast&utm_source=youtube&utm_campaign=betterbrainhealth How to eat in 2026 - Discover ZOE’s 8 nutrition principles for long-term health | https://zoe.com/2026?utm_medium=zoe_podcast&utm_source=youtube&utm_campaign=How to eat in 2026 Gut Guide - For a Healthier Microbiome in Weeks | https://zoe.com/gutguide?utm_medium=podcast&utm_source=youtube&utm_campaign=gutguide Better Breakfast Guide | https://zoe.com/breakfastguide?utm_medium=podcast&utm_source=youtube&utm_campaign=breakfastguide Mentioned in today's episode Dietary Sugar Intake Associated with a Higher Risk of Dementia, Journal of Alzheimer's Disease (2024) | https://pmc.ncbi.nlm.nih.gov/articles/PMC10921393/ Sugar-Sweetened and Artificially Sweetened Beverages and Risk of Mortality, AHA (2019) | https://www.ahajournals.org/doi/10.1161/circulationaha.118.037401 A Twin Study of Acne in Women, Journal of Investigative Dermatology (2002) | https://pubmed.ncbi.nlm.nih.gov/12485434/ Bananas and weight loss: What does the science say? | https://zoe.com/learn/bananas-and-weight-loss? Food Order and Impact on Glucose and Insulin Levels, Diabetes Care (2015) | https://diabetesjournals.org/care/article/38/7/e98/30914/Food-Order-Has-a-Significant-Impact-on Here are 4 ways to help manage your blood sugar | https://zoe.com/learn/4-ways-to-manage-your-blood-sugar Whole Fruits Versus 100% Fruit Juice, BNF (2025) | https://pmc.ncbi.nlm.nih.gov/articles/PMC12398644/ Have feedback or a topic you'd like us to cover? Let us know here: https://gf6hx47iu5g.typeform.com/topicsuggestion Episode transcripts are available here: https://zoe.com/learn/category/podcasts
Key Insights
- Humans don't need to consume sugar to survive because the body can synthesize glucose from protein and fat through biological processes, even though cells require glucose to function
- Repeated high blood sugar spikes stimulate the immune system to create inflammation that travels via the vagus nerve to the brain, potentially causing cognitive decline, Alzheimer's, depression, and schizophrenia
- A large glucose spike causes an insulin overshoot that leads to a dip in circulating glucose 2-4 hours later, which causes people to consume an average of 320 additional calories per day
- Humans evolved to handle episodic high amounts of sugar (like honey binges lasting 2 days) followed by weeks without it, not the continuous low-level sugar exposure in modern ultra-processed foods
- Whole fruit causes a gradual glucose increase with polyphenols and fiber that counteracts inflammation, while fruit juice causes a sharp peak followed by a dip despite containing the same sugar
- Being normal weight doesn't protect against sugar-related health risks because visceral fat around organs can cause metabolic dysfunction without visible obesity
- Switching from sugary drinks to artificial sweeteners maintains the sweet taste sensation, preventing taste bud adaptation and causing continued sugar cravings that lead to eating more calories from other foods
- The brain uses 20-25% of the body's energy despite being only 5% of body weight, making it extremely sensitive to blood glucose control and vulnerable to inflammation-related disorders
- Energy drinks marketed for afternoon energy slumps are essentially high-sugar products branded differently from cola, and most people only need glucose supplementation during exercise lasting over 2-3 hours
- Manufacturers deliberately use multiple different names for sugar in ingredient lists so that sugar doesn't appear as the primary ingredient by weight, intentionally obscuring the sugar content
- Even a 10-minute walk or isometric leg muscle clenching within 20-30 minutes of eating high-sugar food significantly reduces blood glucose spikes by causing muscles to utilize glucose
- Pairing high-sugar desserts with healthy fats and proteins in a meal 30 minutes prior reduces the glucose peak and prevents the subsequent dip that triggers hunger and overeating
Topics
Transcript
[0:00] What's the most common myth that you hear about sugar? >> That all sugar is bad for us, which is absolutely [music] not true. We shouldn't fear sugar itself. The problem is we're now consuming [music] foods that release glucose often very quickly into our bloodstream. >> It's the hidden sugars in many of these ultra-processed foods that you're not actually aware that you're having because they've been masked by other ingredients [music] and chemicals. >> Imagine that I just really want a piece of cake. >> Have that cake, Jonathan. Life is short. But there's a couple of things you can [0:30] do. So, [music] one is >> Professor Sarah Berry is a professor of nutrition at King's…
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