Saturated fats – what’s the story?

Last Updated on January 6th, 2018

If nutrition is a topic that interests you, you’ll no doubt have seen the recent news coverage reporting that saturated fats are not as bad as previously thought. However, the government guidelines on how much fat we should consume in our daily diet has not changed. This currently stands at:

Women: 20g of saturated fats
Men: 30g of saturated fats

Or to put this in context, about 11% of your total daily calorie intake. One of the reasons that saturated fats might not be considered as bad as previously thought is based upon the falling consumption of saturated fat in tandem with unchanging incidence of heart disease. So if we’re eating less butter and fat, how do we account for the same rate of heart disease? None of the media reports have considered what we might be replacing the saturated fats with – sugar? The other problem with these claims is how we look at the science. Unfortunately, the media have a habit of only reporting upon the study that has just been published and don’t look at either the quality of that study or compare it to studies done previously. So it is difficult to make claims about whether a certain food is good for us or not unless you take some time to look at all the available evidence and compare how the studies were done and on whom. The bottom line is, never take your nutritional advice from a newspaper! Always always go to a blog/website/newsletter etc authored by a qualified, scientifically-trained nutritionist/dietitian.

So what is saturated fat?

Saturated fats are those that become solid at normal room temperature. Examples include butter, lard, coconut fat. They exist in most dairy products where the fat has not been removed, such as cheese, cream, milk, and anything made with these. Saturated fats exist in many processed and manufactured goods too. In chemistry, the difference between saturated fats and unsaturated fats are the presence of double bonds within the carbon chains – saturated fats have none, monounsaturated fats have one and polyunsaturated fats have more than one. Unsaturated fats are liquid at room temperature.

So what’s the story?

Well it depends! What these media reports often don’t tell you is (and this is important!) who did they conduct their studies on? Did these people already have a cardiac event or were they from the healthy population and followed up over a number of years? Currently, the evidence suggests that if you have a history of coronary heart disease, you are definitely best reducing your consumption of saturated fats and consider switching to healthier fats such as those found in seeds, nuts, and fish – fats that we call “omega-3 polyunsaturated”. We’ll dedicate a whole post on the different fats another time. For now, it’s important to know that saturated fats are implicated in the increase of “bad cholesterol” in the blood.

If you haven’t had an event, and are considered among the “healthy population”, then the evidence is inconclusive at best. And that is why we have not yet changed the recommendation on the healthy levels of saturated fats.

What is definitely conclusive is the health effects of transunsaturated (trans) fats and thankfully, here in the UK at least, they have been substantially reduced in manufacturing – but not completely eliminated. Unfortunately, we can’t always be sure which products use them – particularly if you like to shop in bakeries and places where you buy your products without an ingredient list. However, high street chains such as Greggs often publish their nutritional information online.

High fat diets

Some studies have shown a connection between high fat diet and some cancers. A recent study on mice suggested that high fats in the diet shift the environment for gut microbiota (bacteria in the gut) which could promote the growth of tumours. It is becoming well-established that the bacteria in the gut have a direct relationship with our immune system and we’ll talk more about that in other posts.

Bottom line
Keep fats to less than 30% of your diet and switch to “healthier fats” such as those found in olive oil, rapeseed oil, nut oils (for salads), avocado oil and consider fish, seeds and nuts as part of your weekly diet (oily fish such as mackerel or salmon is a great way of introducing good oils into your diet). When choosing dairy produce, aim for reduced fat versions but be wary of yoghurts as they sometimes increase the sugar content to compensate – remember, if you’re on a calorie-controlled diet, check the calories on the label. Look out for the posts on calorie-counting soon!

Further reading

Nature (2014) http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13398.html

NHS Choices http://www.nhs.uk/chq/pages/1124.aspx?categoryid=51

British Heart Foundation http://www.bhf.org.uk/heart-health/prevention/healthy-eating/fats-explained.aspx