Fat: why are we so confused about whether or not we should include it in our diet?

Jul 29, 2021

5 min

Dr Duane Mellor

You’d be forgiven for being confused about whether or not you should eat fat. For a long time, people were told to stay well away from it entirely. But lately, fat seems to be back on the table – but only certain types of fat.


With so many conflicting messages about which types of fat to eat, it’s no wonder many people are confused about whether or not they should it. Here are just a few reasons why the advice about fat is so confusing – and how much fat you should really eat.


Some fat is essential in our diet as it gives us energy and helps us absorbs certain vitamins, including vitamin A, D and E. But there are many different types of fats and eating too much of certain types can be harmful to us. Unsaturated fats (also called monounsaturated or polyunsaturated) are known as “good” fats and are important for helping us lower cholesterol and keep our heart healthy. Unsaturated fats can be found in foods such as avocados, olive or peanut oils, and fish.


But saturated fats can be bad for us when eaten in excess, and can raise cholesterol and increase risk of heart disease. Trans fats can also increase cholesterol levels. Foods that contain saturated and trans fats include butter, cheese, bacon, biscuits and fried foods.


Fat is important

Many health authorities worldwide agree fat is an important part of a healthy diet – but that we should only get so many calories daily from fats.

The World Health Organization (WHO) recommends people get no more than 30% of their daily calories from fat – of which only 10% of daily calories should be from saturated fats, and less than 1% from trans fats.


The UK’s recommendations are much the same, limiting saturated fats to only 10% of our daily calorie intake – around 30g per day for men (around 270 calories) and 20g for women (around 180 calories).


But in Europe, health recommendations suggest fat should comprise between 20-35% of our total daily calories. There’s also no recommendations for how many calories should be from saturated or trans fats – just that these should be limited. In the US, people are only advised to limit saturated fat intake to less than 10% of daily calories.


So while there seems to be agreement in how much fat people should eat, the slight variations in these recommendations – as well as variations in how much of certain types of fat we should eat – might explain the confusion over whether or not we should eat fat and how much of it we should eat.


Misleading advice

If all the different recommendations weren’t confusing enough, there’s also a lot of information out there that’s either too simplistic or incorrect. This makes the recommendations about eating fat all the more complicated.


For example, the Joint British Societies (which publishes recommendations to help people reduce their risk of cardiovascular disease) recommends that only around 10% of a person’s total fat intake should come from saturated fats. As typically we consume 30-40% of our calories from fat, and international and government bodies recommend that around 30% of daily calories should come from fat, limiting saturated fats to 10% of this would mean they’d make up only 3% of our day’s calories. This would amount to little more than about 7g of saturated fat -– around two teaspoons of butter.


This differs from many other recommendations – such as from WHO – which states 10% of all the calories people eat daily should come from saturated fats. It’s also unclear whether such a strict restriction of saturated fats would have any benefit and would be difficult for many people to achieve as a variety of healthy foods – such as olive oil – can also contain saturated fats.


There’s also a lot of advice that’s too simplistic, which can be inadvertently misleading.


For example, one tip the British Heart Foundation recommends for swapping saturated for unsaturated fats is to use a spray oil or measuring oils, instead of just pouring it straight from the bottle.


But this doesn’t account for the fact that different types of oil have different saturated fat levels. Sunflower oil, for example, is already low in saturated fat, so using less would significantly reduce calories but only modestly reduce saturated fat levels.


Other advice from the British Heart Foundation includes avoiding frying foods and switching to semi-skimmed milk. But focusing on methods that have a minimal effect on saturated fat levels can make it more confusing to know which foods (and fats) to avoid. The easiest way to avoid saturated fats is avoiding foods like pies, cakes and biscuits. These foods are high in saturated fats and tend to be the greatest sources of them in most peoples’ diets.


Getting the right amount

Research suggests that we should get around a third of our energy from fat – two-thirds of which should be unsaturated fats.


Of course, certain food sources will contain different types of fats, and different levels of fats. For example, avocados and pies are both high in fat. But avocados are high in healthy monounsaturated fats, which are good for heart health and can lower cholesterol. Pies, on the other hand, are high in saturated fats, which can be bad for your heart and cholesterol levels.


The easiest way to make sure you’re eating enough of the right fats is to avoid foods that contain saturated and trans fats – such as butter, hard cheeses, pies, biscuits, pastries, cakes, processed meats and crisps. These foods are also high in salt, carbohydrates and sugar, so can also have other health harms such as increasing risk of high blood pressure.


Instead, try including sources of healthy fats – such as avocados, olive oil, nuts and fish. This will ensure that you’re not only getting enough fat in your diet, but that you’re getting the right kind of fats (around 75g a day for women and 90g for men).


Connect with:
Dr Duane Mellor

Dr Duane Mellor

Visiting Academic

Dr Mellor is an award-winning dietitian, science communicator, medical educator and researcher.

Food ScienceDieteticsDiabetesObesityNutrition

You might also like...

Check out some other posts from Aston University

3 min

Aston University researcher develops new optical technique that could revolutionise medical diagnostics

New light technique could revolutionise non-invasive medical diagnostics Orbital Angular Momentum could be harnessed to improve imaging and data transmission through biological tissues Could eventually have potential to make procedures such as surgery or biopsies unnecessary. An Aston University researcher has developed a new technique using light which could revolutionise non-invasive medical diagnostics and optical communication. The research showcases how a type of light called the Orbital Angular Momentum (OAM) can be harnessed to improve imaging and data transmission through skin and other biological tissues. A team led by Professor Igor Meglinski found that OAM light has unmatched sensitivity and accuracy that could result in making procedures such as surgery or biopsies unnecessary. In addition it could enable doctors to track the progression of diseases and plan appropriate treatment options. OAM is defined as a type of structured light beams, which are light fields which have a tailored spatial structure. Often referred to as vortex beams, they have previously been applied to a number of developments in different applications including astronomy, microscopy, imaging, metrology, sensing, and optical communications. Professor Meglinski in collaboration with researchers from the University of Oulu, Finland conducted the research which is detailed in the paper “Phase preservation of orbital angular momentum of light in multiple scattering environment” which is published in the Nature journal Light Science & Application. The paper has since been named as one of the year’s most exciting pieces of research by international optics and photonics membership organisation, Optica. The study reveals that OAM retains its phase characteristics even when passing through highly scattering media, unlike regular light signals. This means it can detect extremely small changes with an accuracy of up to 0.000001 on the refractive index, far surpassing the capabilities of many current diagnostic technologies. Professor Meglinski who is based at Aston Institute of Photonic Technologies said: “By showing that OAM light can travel through turbid or cloudy and scattering media, the study opens up new possibilities for advanced biomedical applications. “For example, this technology could lead to more accurate and non-invasive ways to monitor blood glucose levels, providing an easier and less painful method for people with diabetes.” The research team conducted a series of controlled experiments, transmitting OAM beams through media with varying levels of turbidity and refractive indices. They used advanced detection techniques, including interferometry and digital holography, to capture and analyse the light's behaviour. They found that the consistency between experimental results and theoretical models highlighted the ability of the OAM-based approach. The researchers believe that their study’s findings pave the way for a range of transformative applications. By adjusting the initial phase of OAM light, they believe that revolutionary advancements in fields such as secure optical communication systems and advanced biomedical imaging will be possible in the future. Professor Meglinski added: "The potential for precise, non-invasive transcutaneous glucose monitoring represents a significant leap forward in medical diagnostics. “My team’s methodological framework and experimental validations provide a comprehensive understanding of how OAM light interacts with complex scattering environments, reinforcing its potential as a versatile technology for future optical sensing and imaging challenges.” ENDS https://www.nature.com/articles/s41377-024-01562-7 Light: Science & Applications volume 13, Article number: 214 (2024) August 2024 https://doi.org/10.1038/s41377-024-01562-7 Authors: Igor Meglinski, Ivan Lopushenko, Anton Sdobnov & Alexander Bykov About Aston University For over a century, Aston University’s enduring purpose has been to make our world a better place through education, research and innovation, by enabling our students to succeed in work and life, and by supporting our communities to thrive economically, socially and culturally. Aston University’s history has been intertwined with the history of Birmingham, a remarkable city that once was the heartland of the Industrial Revolution and the manufacturing powerhouse of the world. Born out of the First Industrial Revolution, Aston University has a proud and distinct heritage dating back to our formation as the School of Metallurgy in 1875, the first UK College of Technology in 1951, gaining university status by Royal Charter in 1966, and becoming The Guardian University of the Year in 2020. Building on our outstanding past, we are now defining our place and role in the Fourth Industrial Revolution (and beyond) within a rapidly changing world. For media inquiries in relation to this release, contact Nicola Jones, Press and Communications Manager, on (+44) 7825 342091 or email: n.jones6@aston.ac.uk

2 min

Aston University researchers to explore using AI and fibre-optic networks to monitor natural hazards and infrastructures

Aston University is leading a new £5.5 million EU research project Will focus on converting fibre-optic cables into sensors to detect natural hazards Could identify earthquakes and tsunamis and assess civil infrastructure. Aston University is leading a new £5.5 million EU research project to explore converting existing telecommunication fibre-optic cables into sensors which can detect natural hazards, such as earthquakes and tsunamis, and assess the condition of civil infrastructure. The project is called ECSTATIC (Engineering Combined Sensing and Telecommunications Architectures for Tectonic and Infrastructure Characterisation) and is part of the Horizon Europe Research and Innovation Action (RIA), which aims to tackle global challenges and boost the continent’s industrial competitiveness. Converting telecom fibres into sensors requires new digital signal processing to overcome the limited data storage and processing capabilities of existing communication networks. To address this the project will use localised, high performance digital processing that will integrate artificial intelligence and machine learning. The researchers’ goal is to minimise algorithms’ complexity while providing extremely accurate real-time sensing of events and network condition. The new laser interrogation and signal processing technologies will be tested using existing fibre optic networks, including those underwater, in cities, and along railway infrastructure to assess their potential. Delivered by a consortium of 14 partners across seven countries, from academic and non-academic sectors, the research will start in February 2025 and will last three and a half years. The Europe-wide team will be led by Professor David Webb who is based in the Aston Institute of Photonic Technologies (AIPT). Professor Webb said: “There are more than five billion kilometres of installed data communications optical fibre cable, which provides an opportunity to create a globe-spanning network of fibre sensors, without laying any new fibres. “These traverse the seas and oceans - where conventional sensors are practically non-existent - and major infrastructures, offering the potential for smart structural health monitoring.” Professor Webb will be joined by fellow researchers Professor Sergei Turitsyn, Dr Haris Alexakis and Dr Pedro Freire. For media inquiries in relation to this release, contact Nicola Jones, Press and Communications Manager, on (+44) 7825 342091 or email: n.jones6@aston.ac.uk

3 min

EU-UK Trade Deal continues to stifle trade with 27% drop in exports since 2021

New report shows persistent stifling effects of the impact of the Trade and Cooperation Agreement on UK-EU trade relations Monthly data show a 27% drop in UK exports and a 32% reduction in imports to and from the EU between 2021 and 2023 Recommendations for policy interventions include to negotiate sector-specific deals, engage with individual EU countries, and work on reducing non-tariff barriers A comprehensive analysis by researchers at the Centre for Business Prosperity at Aston University reveals that negative impacts of the UK-EU Trade and Cooperation Agreement (TCA) have intensified over time. The new report, Unbound: UK Trade Post Brexit, also shows a 33% reduction in the variety of goods exported, with the agricultural, textiles, clothing and materials sectors most affected. To assess the impact of the UK-EU TCA, the authors analysed monthly import and export between the UK and the EU, from January 2017 to December 2023 and separated into pre- and post-January 2021 when the agreement came into force. The monthly data shows a 27% drop in UK exports and a 32% decline in imports from the EU. Lead author, Professor Jun Du of Aston University says: “The Trade and Cooperation Agreement introduced substantial barriers and there are ongoing and marked declines in the value and variety of UK exports and imports. Without urgent policy interventions, the UK’s economic position and place in the global market will continue to weaken.” The UK-EU TCA redefined trade and investment rules and market access between the UK and the EU. Since it came into force, the UK government has negotiated several trade agreements, but the EU remains the UK’s largest trade partner. Exports for most sectors have decreased since January 2021, although the impact is varied. Agrifood, textile and clothing and material-based manufacturing have been among the hardest hit, with substantial declines in both export value and the variety of products exported. At the same time, some sectors such as tobacco, railway and aircraft manufacturing have seen modest increases in varieties of products exported. On the import side, most sectors have shrunk in both value and variety, particularly agrifood products, optical, textile and material-based manufacturing. A few sectors, for example, ships and furniture, have demonstrated noticeable increases in import product variety. The large variations across different goods categories and EU trade partners underscore the uneven effects of Brexit and the TCA on UK-EU trade dynamics, highlighting the need to understand the nuances and come up with tailored strategies that address the unique challenges of each sector within the new regulatory environment. The researchers make recommendations, outlining how sector-specific negotiations, streamlining customs procedures with digital technologies and reducing regulatory divergence could mitigate some of the impacts. Dr Oleksandr Shepotylo, the report’s co-author says: “Our findings indicate a decoupling of the UK from key EU final goods markets, accompanied by a shift in UK supply chains toward geographically closer EU trading partners for exports and smaller countries for imports. “This shift raises concerns and underscores the urgent need for a strategic reconfiguration of UK supply chains to maintain competitiveness.” Professor Du continues: “The TCA has introduced considerable barriers to UK-EU trade, particularly through increased Non-tariff measures (NTMs). “Addressing these issues through targeted improvements to the TCA is crucial to ensuring that UK businesses remain competitive in the European market. A structured, multi-faceted approach is necessary.” To find out more about these findings, click here.

View all posts