One of the things that is often mentioned when people find out I’m a dietitian is how careful I must be about my diet. This statement is usually followed by a list of food fears disguised as questions..
Is bread, bad for me?
Do you really eat pasta?
What are your thoughts on coffee?
or (my all time fav)…
‘so you eat *insert current dietary fad here* too!’
In all honesty, I think being a dietitian means I’m WAY more relaxed about my diet than most. I’m not frightened to have a bit of butter on my *gasp* toast in the morning, or eat at 3pm if my body tells me it’s time. I certainly don’t feel the need to label foods as ‘good’ or ‘bad’, or as one of my friends declared at lunch recently, ‘skinny’ or ‘fat’. SIGH.
However, peoples fears and confusion around what’s healthy have not sprung out of thin air. We are bombarded with mixed messages about what we should eat on a daily basis. Some are based on sound scientific debate, others are clever marketing disguised as legitimate advice and many are presented by people just like us, who have found a diet that works for them and think they must have found the answer to the worlds ills.
Mix this together with a clever blend of food fears, aesthetic ideals and throw in some subliminal body shaming messages and we have the perfect recipe for a media storm.
It’s no wonder people are confused.
Last week was particularly scandalous in the world of nutrition related headlines.
A new study was published which looked at the public health guidelines released in the 80’s that recommended we all eat less saturated fat. The study specifically looked at whether there was sufficient randomised controlled trial evidence (where subjects are put into test groups at random and steps are taken to make sure that it is as fair a test as possible) to make the recommendations to the public. The researchers (correctly) concluded that there was not – and go on to suggest that because of this the guidelines should never have been introduced.
Cue media frenzy and mass hysteria.
However, Before you skip along happily to the pie shop…
What does this study actually show us?
Ahh the 80’s. It was the decade I was born, the years that fashion forgot and an era where smoking in public places, drinking while you were pregnant and perms on men were all considered socially acceptable.
There was also an epidemic of heart disease in America and the government wanted to fix it. In response to the rise in this health problem they reviewed the scientific literature and recommended that people reduce fat to no more than 30% of their total intake, stating that saturated fats should make up no more than 10% of that. In the UK we closely followed suit.
Was there enough randomised control trial (RCT) evidence to make these recommendations? No. But..spoiler alert…It’s not really relevant and there is a reason we don’t base Dietary Guidelines purely on RCT’s.
It’s true that in modern medicine RCT’s are considered the gold standard for assessing how well a medical therapy (like a pill) works. Well conducted RCT’s are designed to reduce the number of things that could influence the study outcome and because of this (unlike other forms of research) they can be used to help determine ‘cause and effect’ (i.e. whether or not a particular action can help make people better).
However, when it comes to diet and health. Things get a little more tricky. It’s nearly impossible to study diet like you would study a pill (both practically and ethically). To determine diet as a cause of disease, we would have to study over a very very long time and know exactly what people were eating from day to day. We know that measuring peoples intake in this way is difficult as people have trouble reporting exactly what they eat. We also know that even when told exactly what to do, people don’t tend to stick to prescribed diets. Thats all aside from the fact it’s hard to separate the impact of diet on disease from all the other factors like our genes and lifestyle.
Because of this, we look at other types of studies as well as RCT’s to influence our decisions about population based recommendations. We look at ALL the available evidence – which is what our current Dietary Guidelines are based on.
The recent study reported in the papers didn’t assess whether our current guidelines are backed up by what we now know, or if we have sufficient evidence (from all sources) to make the recommendations we now make. And so when it comes to influencing what you eat now – this study can’t tell you what to do.
It’s also important to remember that diet guidelines are just that. GUIDELINES. They are not hard and fast rules – they are there to help people choose foods which will benefit their health and not to prescribe a diet.
Ok, But What do We Now Know About Saturated Fat?
It’s true that saturated fat isn’t the demon we once thought it was in the 80’s. But as with everything diet and health related, we are finding it’s a little bit more complicated than it’s either ‘bad’ or ‘good’. The main thing important to note, despite what the papers would have you believe, that new research hasn’t shown us that saturated fat is GOOD for us, or that we should be ADDING extra saturated fat to our diet.
As I said in my post about bullet proof coffee, one of the key things that has emerged from recent research is that when you eat less saturated fat, what you replace it with matters.
Research has shown us that if you replace saturated fat with a whole heap of refined carbohydrate you aren’t going to be healthier and you may end up with an increased risk of disease.
In the UK it’s recommended that total fat intake should be approximately 35% of your daily diet and that saturated fat should make up <10% of that. Replacing saturated fat with unsaturated fats such as olive oil (and not with carbohydrates) has show to have positive effects on our health.
We now know that our whole diet and lifestyle are important when it comes to reducing our risk of disease – not just single nutrients. The current guidelines on dietary fat have not changed and it’s certainly not recommended to ADD saturated fat to your diet (especially in foods like pies, biscuits, chocolate and cakes, which are also a source of refined carbohydrates). These foods should be treated as occasional foods, and if eaten, eaten mindfully, as part of a balanced diet.
Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis
The evidence base for fat guidelines: a balanced diet
Are refined carbohydrates worse than saturated fat?
Joint British Societies’ consensus recommendations for the prevention of cardiovascular disease (JBS3)
Lipid modification: cardiovascular risk assessment and the modification of blood lipids for the primary and secondary prevention of cardiovascular disease
Facts on Fats