ZOE Science & Nutrition

Recap: Fat: The full story | Sarah Berry

11 min
Jan 27, 20264 months ago
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Summary

This episode challenges the decades-long anti-fat narrative, exploring how fat affects health based on type, food matrix, and processing rather than simple dietary guidelines. Host and Professor Sarah Berry discuss why saturated fat's impact varies by food source, how refined carbohydrates affect cholesterol and triglycerides, and why food labels fail to capture nutritional complexity.

Insights
  • Dietary cholesterol consumption has minimal impact on blood cholesterol levels; saturated fat type and food matrix are the primary drivers
  • Fermented dairy products like cheese have similar fatty acid composition to butter but produce different health outcomes due to their unique food matrix structure
  • Food processing fundamentally changes nutrient bioavailability and health impact—whole almonds absorb 60% of energy while ground almonds absorb nearly 100%
  • Refined carbohydrates promote liver lipid production and increase circulating triglycerides, an independent cardiovascular risk factor often overlooked in low-fat diet recommendations
  • Current food labeling systems are oversimplified and fail to account for food matrix effects, potentially leading consumers to make less healthy choices
Trends
Shift from macronutrient-focused nutrition science to food matrix and bioavailability researchGrowing skepticism of simplified food labeling systems among nutrition scientists and health professionalsIncreased focus on refined carbohydrate impact on metabolic health and cardiovascular riskPersonalized nutrition approaches replacing one-size-fits-all dietary guidelinesFood processing methods emerging as critical variable in nutritional outcomes, not just ingredient compositionRehabilitation of saturated fat in fermented and whole food contexts while maintaining caution on processed sourcesMicrobiome health becoming central consideration in food matrix and fiber absorption discussions
Topics
Saturated Fat and Cardiovascular HealthFood Matrix and Nutrient BioavailabilityDietary Cholesterol MythsRefined Carbohydrates and Metabolic HealthFood Processing Effects on NutritionFermented Dairy ProductsTriglycerides and Cardiovascular RiskFiber Intake and Gut HealthFood Labeling LimitationsBlood Sugar ControlWhole Foods vs Processed FoodsPersonalized Nutrition TestingLow-Fat Diet LegacyMicrobiome and Dietary FatBreakfast Nutrition
Companies
ZOE
Host company conducting personalized nutrition testing and research; founder discusses how testing revealed personal ...
People
Sarah Berry
Guest expert discussing fat metabolism, food matrix effects, cholesterol science, and limitations of current nutritio...
Quotes
"Since founding Zoe, I've actually started eating more fat. And that might surprise you, because for decades we've been told to fear it."
HostOpening
"If you consume dietary cholesterol, which is contained from some foods, dietary cholesterol doesn't increase your circulating cholesterol. It's the type of fats that you're consuming that increase your cholesterol levels."
Sarah BerryMid-episode
"Dairy cheese, so fermented dairy such as cheese and yogurt has a really similar fatty acid composition to butter. But actually it doesn't have the same unfavorable effects on our health as butter does. And the reason is because of this matrix."
Sarah BerryMid-episode
"Food is really complicated and it's magical because how we process food has a huge impact on its health outcomes."
Sarah BerryMid-episode
"We need to think about the food. Is it in its original matrix? Is it unprocessed? Does it contain healthy other nutrients like fiber and mono and polyunsaturated fatty acids, rather than looking at that back of pack labelling?"
Sarah BerryLate episode
Full Transcript
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 fat. Since founding Zoe, I've actually started eating more fat. And that might surprise you, because for decades we've been told to fear it. Fatty food will clog your arteries and send you a cholesterol through the roof, right? Well it turns out it's not that simple. How fat affects your health depends on a lot of factors, including the type of fat, the food matrix, even how it's produced. One thing is for sure, that single number on the front of a food packet isn't going to give you the full story. I'm joined by Professor Sarah Berry to dig deeper into fat, uncovering which will harm us and which can help us heal. One of the things that people often ask me is, well how has your diet changed since you started Zoe? And the answer is it's changed a lot. And one of the biggest ways it's changed is that I now eat a lot more fat than I did. I was absolutely sure that fat was bad for me five years ago. My dad was basically put on very low fat diet because he was told he had very high cholesterol in his 30s, so this is now sort of 40, 45 years ago. And so that means that at home, we ate this very low fat diet. As a result, we of course ate lots of carbohydrates because that's what you do to fill it in. And of course lots of refined carbohydrates, pasta and bread and things like this. So I then did these Zoe tests and it turns out that actually my blood sugar control was really quite bad and actually my blood fat control was much better. And so that's what the advice is pushing. But I still feel really guilty when I eat cheese. Even though I've seen this and I also have noticed the way that actually my hunger is lower when I'm eating these high fat foods, I still have this basic feeling that it's a bit naughty, isn't it? Like it's not the right thing to do. What are your thoughts on that, Sarah? I've got loads of thoughts. I'll just touch on a few that I think might resonate with people. So you mentioned about your father, for example, being put on a low fat diet because he had high cholesterol. And this is still a common perspective that lots of people have around. How do I reduce my cholesterol levels? Well, let's consume low fat diets because it contains cholesterol because it will increase my cholesterol levels. The first thing just to mention that I hope most people now are aware of, but in case they're not, is that if you consume dietary cholesterol, which is contained from some foods, dietary cholesterol doesn't increase your circulating cholesterol. So it doesn't actually increase your blood cholesterol levels or it does only to a minimum. It's the type of fats that you're consuming that increase your cholesterol levels. So yes, we know that some saturated fatty acids might increase your cholesterol levels. Can you say what sort of foods those are, Sarah, just for those of us who don't think about things in this chemical way? Yeah. So we know that the kind of saturated fatty acids that are in butter, in palm oil, in animal fats, for example, can increase our cholesterol. Now, cholesterol is made up of good and bad cholesterol. And what we particularly don't want is an increase in good cholesterol alongside an increase in bad cholesterol. And saturated fatty acids increase our bad cholesterol. Some of them do also increase our good cholesterol. So again, it's a little bit more complicated, I'm sorry to say, depending on the type of saturated fatty acid. But what we do now know, which I don't think we were so aware of 30, 40 years ago, is that carbohydrates can have a really big impact also on our cholesterol levels and also on our circulating triglyceride levels, which we also know is an independent risk factor for cardiovascular disease. So if you consume a diet high in refined carbohydrates and by refined carbohydrates, I mean breads, I mean pasta, I mean rice, I mean also a lot of the processed carbohydrates like snack bars, crisps that you might consume. What this does is at the level of our liver, it promotes the production of lipids. So this is another word for the kind of fats that are produced in our body. And that increases our cholesterol levels and increases our levels of circulating triglycerides. But to loop back to what you mentioned about cheese, I think that's a really good example of how we need to move beyond the simplistic approach of thinking about the types of fat. So I just said that actually the type of saturated fat you have in butter is bad for us. Now dairy cheese, so fermented dairy such as cheese and yogurt has a really similar fatty acid composition to butter. But actually it doesn't have the same unfavorable effects on our health as butter does. And the reason is because of this matrix, the kind of special structure in which the fatty acids sit within the dairy products that are fermented within the cheese and the yogurt. So you could feed people a moderate cheese diet and moderate butter diet. The cheese wouldn't have any unfavorable effects yet actually the butter would have an unfavorable effect despite having a similar fat composition. And despite the fact that actually basically the cheese comes from the butter, right Sarah? So that's like even more surprising. Help us to unpack that a little bit. It sounds a bit magical. It is because food is really complicated and it's magical because how we process food has a huge impact on its health outcomes. So how we process dairy whether it's a butter or whether it's a cheese or whether it's a yogurt can hugely impact how our body responds to it. And the same applies for how we process other foods whether it's consuming whole foods or consuming pureed foods or consuming whole almonds or consuming ground almonds where you're changing the matrix. It has a huge impact on this by accessibility that I mentioned earlier. So the release of nutrients and how our body processes them. And I think dairy is a really nice example of how we need to look beyond the nutrients and we need to think about the food that it's actually contained within. So basically the food labels which a vast effort are put onto all of these foods and which in many countries right the states or the UK included talk about sort of saturated or unsaturated are not necessarily really giving you any information that is helpful. Is that what you're saying, Sarah? Yes, in my opinion. I think it's worth mentioning that broadly speaking epidemiological studies. So these big studies that will be following people over a number of years or looking at one point in time in thousands of people and then looking at certain health outcomes and looking at dietary intakes. They do consistently show that a high saturated fatty acid diet is less favorable than a high mono or polyunsaturated fatty acid diet at the population level. But when we do clinical trials, what we know is once we start to tease this apart, it becomes really apparent that that's too simplistic. And at an individual level and at a food level, it's again far too simplistic that we need to consider the type of fatty acids. But more importantly, we need to consider the food it's in. And this is because you're lumping all of these different things together. So you're saying like, well, somebody is eating lots of animal fats. And I think you're you still think animal fats are not particularly healthy. Is that right, Sarah? Yeah. So I would say that you could have foods that contain the same fatty acid composition. So an animal fat and some particular other tropical oils, for example, that contain the same fatty acid composition, but could have different impacts on health outcomes. Because of the source, because of the matrix that they're in has a huge impact. And so I do think that whilst labelling can be useful, broadly speaking, I think we need to be very, very careful to not be too caught up on labelling. And there's an example I often use to do with almonds. Now, this isn't related to the fatty acid composition, but it's related to how I think being preoccupied by labelling can actually potentially even make us select more unfavorable health choices. So if we were to consume whole almonds, almonds have a very special matrix. They have a very rigid cell structure. So what happens is, is that remains intact, largely as we chew them and they pass through our digestive tract. And we only absorb about 60% of the energy. So about 40, 30% of the energy and fat is excreted. So it reaches our large intestine where it's great food for our microbiome, which is fabulous. But also it's a lot lower energy. Now, if we were to grind those almonds up, so we break this magic matrix, we break the cell walls, we release all the fat, we're going to absorb everything. And so that you suddenly have a food that has about a 30 to 40% higher energy content in terms of what we're absorbing than the whole almonds. However, if I was to go into a supermarket and look at a bag that had whole almonds intact, as we typically would consume for a snack versus the whole almonds ground up, like we might use as an ingredient, the back of pack labelling would show that they had identical energy values. They wouldn't show that per 100 grams, you had this huge difference of, you know, several hundred calorie difference. And so I think that's a really nice example of how we need to think about the food. Is it in its original matrix? Is it unprocessed? Does it contain healthy other nutrients like fiber and mono and polyunsaturated fatty acids, rather than looking at that back of pack labelling? That's really powerful advice, right? That in general, thinking more about this is a food rather than as the set of numbers on the back. And of course, all of this labelling, you know, I think it was all being done with good intent, right? But actually isn't very helpful. And of course, if it had been really helpful, then we would have seen all these wonderful health outcomes over the last 30 or 40 years, which we haven't seen either. At Zoe, we never stopped being curious about how people respond to food. So we recently asked thousands of people about their breakfast, what they eat and how they feel about it. Their answers may surprise you. Over 70% told us that their breakfast is balanced, yet only 6% get enough fiber. If you've been listening to this podcast, you know, that's not enough to be balanced. And it's no wonder that only 16% felt energetic after eating. Clearly, breakfast is broken. But what if you could get a breakfast that actually supports your energy and gut health? Meet Daily 30, our 30 plant gut supplement that's out to fix breakfast one scoop at a time. Daily 30 is designed by Zoe Gut Health Scientists and features four grams of fiber and ingredients that support gut health, digestion, energy, immunity and skin and hair. 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