This blog post covers the transcript of an enlightening and insightful session on the complex world of dietary fats. This online event dived deep into the compelling interplay between dietary fats, glucose control, and metabolic health.

Our esteemed guest is Dr Joanna McMillan, an Accredited Practising Dietitian and PhD Nutrition Scientist, known for her commitment to practical, evidence-based guidance. Joanna's credentials extend beyond dietetics, as she is a respected author, TedX speaker, and frequent commentator on television and radio. With her extensive knowledge and experience, Joanna will discuss the intricate relationship between fats and metabolic health.

Guiding the conversation are our hosts, Dr. Michelle Woolhouse and Charlotte Battle. Dr Michelle Woolhouse, Vively’s medical director, is also a practicing integrative GP, a podcaster, and an author, who lends a wealth of experience and perspective to the conversation. Charlotte Battle, Vively’s Accredited Practising Dietitian and personal trainer, will provide valuable insights from her background in nutrition and fitness.

Topics we cover into include:

• The different types of dietary fats
• How fats impact metabolic health and insulin sensitivity
• The benefits and risks of a high fat/low carb diet
• The latest research on fats and metabolic health, and so much more

Expect an insightful conversation full of evidence-based knowledge that can bolster your health journey and overall wellbeing.

Watch the full video here: Unpacking fats: a deep dive into fats for metabolic health with Dr Joanna McMillan

Charlotte:

Welcome to our fireside chat. Today, we'll delve into a deep dive on fats, especially in the context of metabolic health. I'm Charlotte, the accredited practising dietitian here at Vively. Before we begin, I'd like to acknowledge the traditional owners of the land we meet on today and pay my respects to the Elders, past and present.

We're honoured to have Dr. Joanna MacMillan with us. Joanna is an Accredited Practising Dietitian, a PhD nutrition scientist, an author, a TEDx speaker, and a prominent figure in TV and radio. We're thrilled to have her expertise.

Joining us also is Dr. Michelle Woolhouse, our integrative GP, keynote speaker, author, and the medical director here at Vively.

As we proceed, feel free to turn on your video; it adds a personal touch. If you have questions, jot them down in the chat, and we'll address them during the Q&A at the end. For those who can't make it, we'll be recording this and sharing the link later.

Michelle:

Thank you, Charlotte. Hi, everyone. I extend my warm welcome to this fireside chat. Jo, it's wonderful to see you again, and I'm grateful for the science-based nutrition work you're doing. It's a treat to have you here today.

Given the mixed messages about fats, despite decades of research, there's still a lot of confusion. Fats have been categorised in so many ways: good fats, bad fats, brown, white, omega-3, 6, 9, saturated, unsaturated, and more. It's no wonder people are overwhelmed. Let's go back to the basics: what are fats, what do they do, and how do they impact our metabolic health?

Joanna:

Great question, Michelle. It's crucial to distinguish between dietary fats and body fats. Body fats have significant roles, like storing energy and producing certain hormones. Fats in our diet come in various forms, and it's not just about the type of fat; it's also about the foods containing these fats. The term "food matrix" is essential here. For instance, full-fat dairy, despite its saturated fat content, doesn't necessarily increase heart disease risk due to its unique matrix.

Michelle:

That's an insightful way to view fats. Let's also discuss essential and non-essential fats, particularly the role of omega-3 fatty acids.

Joanna:

Only two fatty acids are truly essential, meaning our bodies can't produce them and they must come from our diet. Omega-3s are essential because our body has a limited capacity to produce them. For example, I've found that my body isn't efficient at producing long-chain Omega-3s, so I ensure I get them from sources like oily fish. While we can produce other fats like saturated fats, it's essential to understand how different fats influence metabolism. Genetics also plays a role in how fats affect us.

Michelle:

You've touched on the importance of visceral fat, which is often associated with problematic sugar levels. Can you expand on this? While weight gain around the midsection is one visible sign, some might not even show it externally. How should we approach this?

Joanna:

Visceral fat is vital to understand. It's not the fat we can pinch around our waist but the fat around our internal organs, located beneath the muscle layer. That's why someone might appear lean but still have a significant amount of visceral fat. A DEXA scan is the best way to measure it. One of the main ways to tackle visceral fat is through exercise, which helps regulate blood glucose and cholesterol levels. I'm a proponent of high-intensity interval training (HIIT) as it's time-efficient and effective. But daily activities, like walking, can also make a difference. Diet-wise, controlling blood glucose levels by reducing refined carbs and added sugars is key. And while I advocate for extra virgin olive oil (despite my affiliation with a company in this sector), I've always backed its benefits. People who consume it as a primary fat source often have reduced visceral fat levels. Genetics also play a role in our visceral fat levels. Some might find it harder to manage than others due to genetic factors.

Michelle:

Dietitians in the 80’s and 90’s were all about low-fat diets, but the narrative has evolved over the years. With the popularity of keto, Mediterranean diets, and more, is there still a place for low-fat diets?

Joanna:

The low-fat approach originated primarily for weight control. Fat has more than double the energy of carbohydrates, so reducing fat seemed logical for calorie reduction. While studies from that era did show weight loss benefits from a low-fat diet, the most significant takeaway from all weight loss studies is compliance. Whether it's low-carb or low-fat, the best diet is the one an individual can stick to. Everyone's needs are different based on genetics, metabolism, activity levels, and cultural background. For instance, someone from a Mediterranean background might thrive on a Mediterranean diet, while someone from Asia might prefer a more Asian-centric diet. The key is individualization. Prioritise healthy fats like extra virgin olive oil, oily fish, nuts, seeds, and avocados. The specific amount will depend on one's unique makeup.

Michelle:

Michelle:

Absolutely. Given the abundance of information and marketing around diets, it's essential to focus on individual needs and lifestyles.

It often feels like we're pulled in different directions with diet advice. It's refreshing to hear an approach that emphasises personal preferences and listening to our own bodies.

Joanna:

Absolutely. In my talks on personalised nutrition, I emphasise the foundational principle: a whole-food diet that minimises ultra-processed foods. From there, your dietary choices can adapt to your medical conditions, allergies, food intolerances, microbiome, genetics, cultural background, and personal tastes. For example, if you don't like kale, there are plenty of other healthy vegetables to choose from. Unfortunately, diet discussions can become tribal, almost cult-like. With over 40,000 diet books, each claiming to have the answer, it's essential to remember that humans are adaptable and can thrive on various diets.

Michelle:

I love the saying, "There are no essential foods, only essential nutrients." This perspective gives people the freedom to choose foods they enjoy and fit their lifestyles. With the rising popularity of keto and low-carb diets, what does the evidence suggest about their effectiveness?

Joanna:

I view keto as a therapeutic diet. While there is evidence for its use in certain conditions, such as epilepsy in children, there's limited long-term data on its impact for the general population. It's challenging to maintain, and many who claim to follow keto might just be on a low-carb, high-protein diet. Keto can affect the gut microbiome due to its low fibre content. If someone chooses to follow a keto diet, I recommend taking a fibre supplement. While some studies suggest it might benefit those with significant obesity, it's not a magic bullet. True keto can't be done intermittently, like a few days a week. While low-carb diets can be effective for some, it's all about personal preference.

Michelle:

Nutritional medicine often involves therapeutic diets to address specific health concerns. Is it necessary to maintain strict diets after a condition has been addressed? Also, can you tell us more about trans fats and their impact?

Joanna:

Trans fats are mostly found in ultra-processed foods. They occur naturally in some animal foods, but in negligible amounts. The majority come from hydrogenation, a process where unsaturated fats are bombarded with hydrogen to make them behave more like saturated fats. This chemical process creates trans fats, which are harmful, even in small amounts. Places like New York City have banned them, and while Australia hasn't officially banned them, many products advertise as having zero trans fats. However, it's crucial to read ingredient labels and watch out for terms like "hydrogenated oil."

Charlotte:

There's been a lot of debate around whole food fats versus oils. Can you shed some light on this?

Joanna:

Absolutely. When we talk about fats from whole foods versus those from oils, we're really discussing the difference in how these fats are presented to the body. Whole food fats come with a range of other beneficial components, such as fibre, protein, and various phytochemicals. These components can influence how fats are digested and used by our bodies.

Take avocados, for example. When you eat an avocado, you're not just getting healthy fats. You're also consuming fibre, vitamins, minerals, and beneficial phytochemicals. This whole food matrix provides a synergistic effect on health.

On the other hand, while avocado oil is certainly a healthier choice compared to many other oils, it doesn't provide the fibre or as many phytochemicals as the whole avocado.

This doesn't mean oils are detrimental. Quality oils, especially those that are cold-pressed or virgin, can be healthful in moderation. Extra virgin olive oil, for instance, is packed with polyphenols known for their health benefits.

Oils serve as a cooking medium, but I emphasise extra virgin olive oil because it's essentially fresh olive juice. In contrast, oils like canola or rice bran undergo rigorous refining processes involving heat, pressure, and chemicals. Extra virgin olive oil, coconut oil, butter, and animal tallow have been in human diets for centuries, if not thousands of years. The idea is to consume whole foods for their comprehensive benefits. When it comes to cooking or dressing, consider the dish and flavour profile. For salads, choose an extra virgin olive oil that complements the salad's delicacy or robustness.

Charlotte:

It's interesting that you mention frying. There's a misconception that olive oil isn't suitable for cooking due to its smoke point.

Joanna:

That's a myth. Research, particularly from the Cobram labs, shows that the smoke point doesn't determine an oil's cooking suitability. Oils marketed for frying, like canola and rice bran, deteriorate faster when heated. Extra virgin olive oil, on the other hand, is protected by its monounsaturated fats and its vitamin E and polyphenol content. We should be cooking with extra virgin olive oil, using it for frying, marinades, and even barbecues.

Charlotte:

It's amazing how our understanding of oils has evolved. In my university training there was still recommendations to use rice bran oil for cooking and now the research is certainly catching up.

Joanna:

Nutrition science is intricate. Our understanding builds over time. We shouldn't discount everything we once knew, but rather, build upon it. The science continues to evolve, and it's important to keep up with the latest findings.

Charlotte:

And speaking of advancements, there seems to be a surge in individualised nutrition based on genetics. Can you tell us more about genetic tests for understanding fat metabolism?

Joanna:

Sure, I've tried a test from Nutrigenomics, a Canadian company. They analyse genes that influence diet and lifestyle. This isn't about predicting diseases but making positive changes. The results, for instance, can tell you about your salt sensitivity, caffeine metabolism, or fat metabolism. The key is to use these insights to motivate positive dietary changes.

Charlotte:

I find that fascinating. And with new technologies like continuous glucose monitors, we can get even more personalised insights into our diet and health.

Joanna:

Absolutely. Monitoring technologies, combined with genetic and microbiome testing, will revolutionise personalised nutrition in the future.

Charlotte:

Joanna, thank you for sharing your insights today. Before we conclude, I'd like to mention that Joanna has an Audible series on heart health, which I highly recommend. We'll share the link in our community. Our next session in August will delve deeper into carbohydrates with Dr. Jessica Turton. Thank you, everyone, for joining, and we'll see you next time!

Joanna:

Thank you for having me!