ZOE Science & Nutrition - Most replayed moment: Carbs: the good, the bad, and the misunderstood | Tim Spector

Episode Date: March 17, 2026

Today we’re talking about carbohydrates. Pasta, potatoes, fruit and beans - carbs crop up everywhere. However, few topics in nutrition cause as much confusion. Are they essential fuel or the enemy of weight loss? Should we cut them down, or just choose our carbs more carefully? I’m joined by Professor Tim Spector to help untangle the truth and answer your biggest carbohydrate questions. Stick around to find out if freezing your bread makes it healthier. 🌱 Try our new plant based wholefood supplement - Daily30+ *Naturally high in copper which contributes to normal energy yielding metabolism and the normal function of the immune system 📚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 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 Have feedback or a topic you'd like us to cover? Let us know hereListen to the full episode here

Hello and welcome to Zoe Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today, we're talking about carbohydrates. Pasta, potatoes, fruit and beans. Carbs crop up everywhere. However, few topics in nutrition causes much confusion. Are they essential fuel or the enemy of weight loss? Should we cut them down or just choose our carbs more carefully? I'm joined by Professor Tim Specter to help untangle the truth and answer your biggest carbohydrate questions. Stick around to find out if freezing your bread makes it healthier.

So what is a carb and what is it that can make it unhealthy? Well, a carb is a macronutrient. So in the old school world that we used to know, everything was divided into these three groups of proteins, fats and carbs. and most other things we eat are mixtures of those rather than one thing. You don't actually eat a carb. You eat a plant, and that plant will have different amounts of proteins, fats, and carbs in it. And within the carbs, it's going to have different types of carbs in it. And some of the foods we eat, which you say, oh, that's a carby food, like, say, bread,

is also going to have some protein in it and a little bit of fat in it. So we tend to massively oversimplify, but that's what we've done in the past, mainly through ignorance, and the food companies have liked it that way because it's made it very easy to sell products to us. Now, I think we need to break down carbs into what they are, which they are essentially sugars that are either very simple, sort of moderately simple, and really complex and long and hard to break down. So the simple sugars, like sucrose, you know, your table sugar, is a very simple carbohydrate, it's a very simple sugar.

It means it only has a few bonds, easily broken down and used by your body as energy. Then you've got the starches, which are slightly more complex, storage forms of sugar, which are joined together by bonds, which can be broken down by other enzymes in your body. and every plant has these starches and we're designed to do them. So they break it down into simple sugars, which are then released, just takes a little bit longer. And then you've got the really complicated long sugars all joined together with lots of tight bonds that are called fibres. And these are sometimes really impossible to break down in the body and only by the gut microbes sometimes rather than ourselves. And they pass through the body. So you've got this complexity all the way from simple to very long and complex with very different effects on the body.

So most people think of carbs as only the sort of sugary end ones. They forget the lot of the healthy carbs are these complicated fibres at the other end. So they throw the baby out with the bathwater. So I'm not having any carbs. It's all rubbish. They're all deadly. Well, that's not true. So many questions.

I just want to pick this one out first because it seems like directly relevant. which is, Tim, what are the good carbs that you eat? Well, I eat as much as I can find. So basically, you name it, I'm trying to eat it. But, you know, I make my own sourdough bread and I make sure it's got plenty of rye in it. And if I find some nice German rye bread, that to me is a good carb because it's very hard to digest. So it's very slow to break down that rye. I'll have pasta rather than rice.

So I still occasionally have traditional wheat pasta, but increasingly switching to whole grain, whole wheat pastors, which are better for me. And then you've got all these range of grains, so things like lentils, quinoa, balka wheat, pearl barley, instead of rice. So they're sort of little ones that people don't often think but I certainly didn't think about those 10 years ago.

So increasingly, I'm making these swaps as I'm trying to move away from the traditional staples. And whole grains and beans. I've heard you mention these are sort of the go-to things replacing the rice and the potatoes and the potatoes. Yes, so we haven't mentioned legumes and beans, but absolutely they're a source of, you know, fats as well. So, again, you know, what's a carb source? It gives you the energy. You know, you break down the sugars slowly, but it's also got protein. It's also got fiber.

So legumes are, yeah, I can't get enough of those beans and lentils in every dish I'm finding. As well as the classical ones, you know, we haven't talked about the spinach and the kale's and the whatever. So there goes without saying they're in there. But I think it's about the little swaps people can make to move away from the too easy to digest ones, the ones that give you those sugar spikes. I had to say the thing that I found easiest is swapping regular pasta for whole grain pasta. And I know it's really easy because my daughter had a play date yesterday. And I gave them pasta.

We have whole grain pasta now in house. Gave it to her friend who's never had whole grain pasta before, I think. And she just ate it because, you know, it has cheese and whatever else. She's like delicious. So that one is so easy to make the change. And I remember being like really, oh, that's a disgusting idea. And I think within a week, I was like, oh, it's completely normal. So I found that very easy.

Whereas I think other things are obviously harder, right? To re-engineer to eat less bread, for example. We have to really rethink the sorts of food because you can't just get us, you know, if you were just always eating a sandwich, then that doesn't really work as much. And so some things are harder and some things are easier, Tim, to change? Definitely, yes. So you've touched on some of them. And some of these areas are new.

the foods are evolving. So you might have tried, you know, whole wheat pasta five years ago, but the new ones are actually tasting better. Similarly with the chickpea pastors or the lentil pastas, you know, they're getting better all the time. They don't fall apart like they used to. Another question we had so much. When is the best time of day to eat carbs? Great question. The literature tells us that it's the mornings that are the best time. that we metabolize better, so eating an identical carb meal, we have seen to have better control over it, will bring those sugar levels down quicker, digest it faster than in the evening. Now, the only caveat is those studies were generally done on young people, 20-year-olds.

And when we looked at the Zoe data, we found that really this time difference pretty much disappeared after the age of 50. So the advantage is for young people may be less relevant because young people really, apart from possibly mood changes, aren't really going to suffer many metabolic changes from having these spikes. Whereas as you get older, where it's more important, there seems to be more individual differences. So some people might be early, you know, better in the morning, some people might in the evening. So I don't think there's a rule. And I think you should follow whatever practice suits you. and is likely to be sustainable.

And so that's why I still have most of my carbs in the evening, because I know it doesn't affect me more than the morning, and it's when I'm hungrier. So my natural body tells me to do that. So listen to your body, I think, is the rule here. And just because some studies have shown young people, you know, it is better. If you can eat in the morning, that's fine, but don't get obsessed with it. And you mentioned the Zoe data here.

Is this a big data set that helps to inform what you're saying? We've looked at thousands of people's data with Zoe who've done glucose monitors and clearly this age effect and time of day is very different in young and old people. Next question. Does eating carbs with other foods at the same time affect blood sugar spikes? Absolutely, yes. So what we're doing, if you eat it with other foods, you're essentially wrapping the sugars in other foods that are harder to digest. So whether they're fibers that

their body can't break down or it's encased in fats is really important. So that's why the important of thinking about food in combination, thinking about what's on your plate rather than any one ingredient is really important here. So mindful eating, realizing that if you are going to have, for example, some bread, you've got no healthy bread, but you've got no healthy bread, you're starving, well, just have it with some cheese or try and balance these things up so that, or, you know, take it with a handful of nuts to give you some extra fibre. These have been shown quite clearly to change the height of the sugar spikes, which will then reduce the consequences. So it's not an absolute cure all for everything, but it will mitigate

in a way that sugar spike. So you can start to balance it. And do you need to sort of soak the food in that fat? So, you know, I'm thinking, because I sometimes feel like, oh, I've got that pasta, but as long as I pour loads of olive oil over it, like maybe it's going to be, like, slower to break down. Does it need to be, like, soaked in it? Or can I just have the two, like, one mouthful and one of the other? But clearly it's hitting my stomach is not actually sort of encased. I think as long as it gets into your stomach, the stomach is like a washing machine where it churns it all up.

So I'm not a big fan of people saying, well, I'm going to have my fats 10 minutes before I have my carbs in order to get this response. I believe that generally our stomach is able to sort these things out. So if we're eating them at the same time, this should solve that problem. So I'm a bit against this obsessional eating that you have to divide your meal into 10 minute intervals, having your cheese before you have your salad. and then your potatoes, I think that's going a bit too far because for most purposes, your stomach will treat it all the same. And does eating like a sort of refined carb with some other food, does that suddenly make it as good as eating a sort of whole grain or unrefined carb in the first place? No. You can't put sprinkle on a turd.

It's still going to be a sugar. And it's always going to be better to have those whole grains because you've got the original nutrients of the carbohydrate, you know, the brown, the germ, all these things on the casing that big food takes away. In those foods we're talking about, the good carbs, then they will still have them. And you can't replace that just with a food tablet or just a bit of cheese. I have to say my own personal experience when I was doing the first sorry studies with you, Tim, was that I was wearing this. blood sugar sensor and I ate a big pizza. And obviously pizza got lots of cheese on it, right? So there's lots of fat as well as this, you know, sort of bread underneath, right, which is carb.

And I think I had the biggest blood sugar spike in the entire two weeks from this big pizza. It went off the roof, stayed high for so long, then finally collapsed later. And I know that I don't have very good blood sugar control. But it did definitely make me feel that I wasn't going to just be able to put a bit of cheese on like a piece of bread and magically not have any blood sugar spike. Is that very unusual response that I had? Well, everyone's different, but there's plenty of people like you, and we all respond differently to fats and sugars, as we know.

But I think it's a mistake to think that you can have unhealthy carbs, like a massive pizza base, and just smother it with all kinds of unhealthy fats, and which might mask that sugar spike. but remember the fats, this is another podcast, but at six hours, your body's still trying to get rid of those fats in your body and can cause more problems than the sugar. So let's not swap one problem for another. You know, pizzas are fine, have them every now and again, enjoy it as a treat. You know, maybe have your salad as your starter, which does help prime your blood sugar, but don't get too crows. crazy on the extra fats.

I think one of the things that this has done is just changed my mind. To think about a lot of these things more like treats than as just sort of the, oh, you must eat this because this is your source of energy and you need to, you know, if you're not eating lots of bread before you go out in the morning, then, you know, how could you possibly function in the day? But another question that came out surprisingly often, does freezing your bread make it healthier? Great question. And this is this whole question of what's called resistant starch.

So bread is a good example, but it could be, the question could also be for pasta, could also be for rice. And it comes from these studies that showed that if you cook these products and then the next day you put them in the fridge, then you reheat them, that they could be healthier. because in some way the starch, the sugars, have become more resistant to digestion. That's why they're called resistant starches. And so they actually became more like fiber. About 10 years ago when I first looked at it, so it was more theoretical than real. But the last few years, there have been a number of studies now showing quite consistently that you get a benefit on the amount of sugar that comes out of that food and the sugar spikes

if you do this for for rice, for wheat, for pastors. And, you know, I was very skeptical, but now I think actually it's quite reasonable. I'm not sure that I'd always want to be cooking everything two days in advance and leave it in the fridge. But it's sort of an extra reason to have those leftovers and do batch cooking for many people because it will slightly improve how much, you know, goes down to your gut and how much less is released. So, yeah, whether long term it's a technique, I don't know. But it's quite a fun thing to think about. I'll end this episode with something I think you'll like, a free Zoe gut health guide.

If you're a regular listener, you know just how important it is to take care of your gut. Your gut microbiome is the gateway to better health, better sleep, energy and mood. The list just goes on. But many of us aren't sure how to best support our gut. I wasn't sure before doing Zoe, which is why we've developed an easy-to-follow gut health guide. It's completely free and offers five simple steps to improve your gut health. You'll get tips from Professor Tim Specter, Zoe's scientific co-founder and one of the world's most cited scientists, plus recipes and shopping list. straight to your inbox.

We'll also send you ongoing gut health and nutrition insights, including how Zoe can help. To get your free Zoe gut health guide, head on over to zoey.com slash gut guide. Thanks for tuning in and see you next time.