Is one type of fat healthier than another? Which foods are high in saturated fat, and which are high in unsaturated fat? EatingWell answers your top questions.
Reviewed by Dietitian Lisa Valente, M.S., RD
Do you remember the days when all fats were bad? That's right—a few decades ago it didn't matter what type of fat you were referring to because they were all nearly verboten. No surprise, times have changed. Today there are some fats that we're told to eat multiple times a week (hello omega-3 fats!). It's now well-known that eliminating fat altogether is not the healthiest route. But some fats are more worthy (health-wise) than others.
We're going to give you a primer on each and teach you which ones are healthier. But first: there are three main types of fat—saturated, unsaturated and trans. Trans fats are predominantly man-made and are the worst health-wise; so much so that they've been banned in the U.S.
Then there are saturated fats and unsaturated fats. Here's the skinny (pun intended!) on those two.
What are saturated fats?
What differentiates the types of fat is how they're built (meaning their chemical structure), and then because of their chemical structure they function differently in our bodies.
What foods are they in?
- Butter
- Ghee
- Lard
- Oils that are solid at room temperature, like coconut oil
- Whole milk & other full-fat dairy products
- Cheese
- Red meat & processed red meats
- Baked goods
fatty meats, avocado, salt, butter, cheese, eggs, mayonnaise, sauces, creams
Credit: Getty Images / Ulrika
What are unsaturated fats?
Unsaturated fats are liquid at room temperature (not solid like saturated varieties). Structurally, they don't have as many hydrogen atoms bonded to carbon atoms (i.e., they're less saturated). Within the category of unsaturated fats, there are two main subcategories—monounsaturated fats and polyunsaturated fats. Both monounsaturated and polyunsaturated fats have heart-health benefits, though polys seem to have a slight edge over monos. Learn more about 4 foods to choose the full-fat versions over reduced-fat.
What foods are they in?
- Oils that are liquid at room temperature (i.e., vegetable, nut & seed oils)
- Nuts
- Seeds
- Fatty, oily fish, such as salmon, tuna, trout, etc.
- Avocado
Which fats are healthier—saturated or unsaturated fats?
- Many studies have found that people who eat more unsaturated fat and less saturated fat have lower rates of cardiovascular disease—as well as lower rates of other major causes of death. So, you see, it isn't just about heart health.
- Also, in studies where people replace some of their saturated fat with unsaturated fat (particularly polyunsaturated fat) their risk of cardiovascular disease diminishes significantly (about 30% per this AHA report). Some studies found this dietary shift to be as effective as taking a statin.
- Other research has shown that people who eat a lot of saturated fat eat less of other nutrients, like unsaturated fat and/or carbohydrates. In other words, more saturated fat in your diet could potentially edge out those known healthy unsaturated fats.
- One particular type of polyunsaturated fat—omega-3s—has ample science-backed health benefits. Research has shown omega-3s have potential brain- and heart-health benefits, as well as other anti-inflammatory properties that are beneficial for various conditions.
Bottom line
Overall, the Dietary Guidelines for Americans says you should limit your total fat intake to 25 to 35% of your daily calories. The recommended saturated fat cap is slightly more rigid: the Dietary Guidelines for Americans says less than 10% of your daily calories should come from saturated fat; the American Heart Association says cap it at 5 to 6% of your calories if you have high ("bad") LDL cholesterol. In case you're curious, the average American gets 11% of their calories from saturated fat.
Even though there is a limit on how much fat you should eat each day, that doesn't mean that less (or really a lot less) is better. Your body needs fat: not only is it a source of energy to keep us moving through life, but fat also plays a key role in essential body functions, and without it your body can't absorb some vitamins and minerals. As with most nutrition advice, though, moderation reigns supreme.
Click here to see the infographic
While fat in general plays an important part in a healthy diet, the kind of fat in your food – either saturated or unsaturated fat – is something to consider when preparing snacks and meals.
Saturated and unsaturated fats are present in many of the foods we eat. Understanding the differences between the two types, which foods are the main sources, and the potential impact of these fats on health can help you make better choices as you cook and shop.
Saturated and unsaturated fats are different kinds of fat, found in different amounts in different foods. While full fat dairy products such as butter and cheese and fatty and processed meats (as well as many baked and processed foods like cakes and biscuits) are high in saturated fat, good sources of unsaturated fats include nuts, seeds, and vegetable oils*.
One of the most relevant aspects of the difference between these types of fat is in the impact they can have on health.
Saturated vs. unsaturated fat
Replacing saturated fats with unsaturated fats in the diet has been shown to lower blood cholesterol – one of the risk factors in the development of heart disease**. In the UK on average we currently eat more saturated fat than is recommended.
So paying attention to the amount of saturated fat vs. unsaturated fat in your diet, and opting for unsaturated options where possible, is a positive step for heart health**.
Here’s an infographic to help you understand better the difference between saturated and unsaturated fats:
What is the difference between saturated and unsaturated fats?
So what are saturated and unsaturated fats, structurally speaking? The difference between saturated and unsaturated fat lies in the number of double bonds in the fatty acid chain. Saturated fatty acids lack double bonds between the individual carbon atoms, while in unsaturated fatty acids there is at least one double bond in the fatty acid chain.
Saturated fats tend to be solid at room temperature and from animal sources, while unsaturated fats are usually liquid and from plant sources.
Saturated fat and unsaturated fat: Making changes to your diet
- Know the guidelines for the recommended maximum amount of total fat, and the maximum amount that can be saturated. According to the NHS website, the current recommendation on fat for adults equates to a maximum of around 70g of fat a day, of which no more than 20g should be saturated.
- Read nutritional labels, such as the reference intake (RI) information on the front of packets, to find out how much saturated fat is in foods. A lot of prepared foods have a label on the front of pack indicating the quantity of fat per portion, and the proportion of that amount that includes saturates. These can help guide your food choices throughout the day and help you choose foods that are lower in saturated fat.
- Reduce the amount of saturated fat in your diet and replace with some unsaturated fats. To help reduce your intake of saturated fat, you can limit foods that are high in saturated fat, like cakes, pastries and chocolate. You can also choose lower fat alternatives for dairy products like swapping full fat milk for lower fat milks or swap butter for reduced fat spreads. As for fatty meat and meat products, you could exchange these for poultry like chicken or turkey without the skin or for lean cuts of meat, which are lower in saturated fat. You can find more ideas to help you reduce the saturated fat in your diet in our simple swaps guide.
- Eat more unsaturated fat…
Nuts and seeds, as well as vegetable oils and spreads, are a good source of unsaturated fat – consider adding about a tablespoon of nuts and seeds as a topping for cereal, salads or porridge, or even enjoying them as a snack.
So, if you want to work on your cholesterol levels, swapping saturated fats for some unsaturated fats is a good way to start. Why not download our Cholesterol Lowering Starter Kit and make a start today?
* Unsaturated vegetable oils include rapeseed, olive and
sunflower oil, but do not include palm or coconut oil.
**Replacing saturated fats with unsaturated fats in the diet has been shown to lower blood cholesterol***.
***High cholesterol is a risk factor in the development of coronary heart disease. There are many risk factors for coronary heart disease and it is important to take care of all of them to reduce the overall risk of it.
Key references
- Scientific Advisory Committee on Nutrition (2018). Draft report: Saturated Fats and Health. (accessed 16 May 2019).
- Hooper L et al. (2015) Reduction in saturated fat intake for cardiovascular disease. Cochrane Database of Systematic Reviews(6)
- Roberts, C., Steer, T., Maplethorpe, N. et al.(2018). National Diet and Nutrition Survey Results from Years 7 and 8 (combined) of the Rolling Programme (2014/2015–2015/2016). London: Department of Health and Food Standards Agency.
- European Commission (2016) EU register on nutrition and health claims. (accessed 16 May 2019).
- NHS (2017) Fat: The Facts. (accessed 16 May 2019)
- Stanner S & Coe S (2019) Cardiovascular Disease: Diet, Nutrition and Emerging Risk Factors, 2nd Edition, Keith N Frayn, Chair.Wiley-Blackwell: Oxford, UK.
The British Nutrition Foundation has reviewed the accuracy of the scientific content of this page in May 2019 (please note this does not include linked pages). The Foundation does not endorse any brands or products. For more information about the Foundation, please visit www.nutrition.org.uk
This information has been included in good faith, but is for general informational purposes only, and should not be construed as a guarantee. The nutritional facts and statements on this site are designed for educational and resource purpose sonly, not being substitutes for professional advice. If you have any concerns or questions about your health, you should always check with your GP or healthcare professional.