Low fat, high fat? ...make your mind up
The food pyramid promotes eating fats sparingly, but a recent study seems to be telling us that we need to eat considerably more. So what to do? Our resident dietitian Orla Walsh is on hand to decode the science
A study published in the Lancet journal made the front cover of many newspapers worldwide. The data is from the Prospective Urban Rural Epidemiology (PURE) study and was led by researchers at McMaster University and Hamilton Health Sciences. It followed more than 135,000 people from 18 low-income, middle-income and high-income countries.
The study asked people about their diet and followed them for an average of seven-and-a-half years. They used food frequency questionnaires - they're not as accurate as we would like, but they're used a lot in research.
The study aimed to observe its participants over time to see if they can statistically find relationships between observations. This was not the type of study we use for cause and effect. It does serve as an excellent hypothesis-generating study that could lead onto other controlled studies.
So what made it this study so special?
1 First and foremost, this study considered more than just Europe. Up until now, dietary guidelines are based on results from studies which are mainly from Europe.
Obviously this means that the current guidelines would be more suited to us Irish rather than those in North America.
This study was special as it considered countries in North America as well as Europe, including low-, middle- and high- income countries. Therefore they feel that the world nutrition guidelines should be adjusted according to their results.
What may be better is to tailor the guidelines to the particular countries instead of trying to get a more general guideline to fit everybody. After all, we know that ethnicity as well as socio-economic status influence disease risk.
2 This particular paper suggested that instead of quarter of our calories coming from fat, one third of our calories should come from fat. If we did this, we would have a 23pc lower risk of dying.
Now, while this is being touted as ground-breaking stuff, it's actually not. We knew this. The Food Standard Authority of Ireland has the Reference Intake for fat set at a little more than 30pc. Yes, this study showed that adequate intake of fat was good for us. Well, duh... fat helps absorb the likes of vitamin A, D, K and E. Fats also give us nutrients that are essential to life and if not eaten in sufficient quantity, our body can't make them, and thus health suffers. For example, the much discussed and much encouraged omega 3 fatty acids.
3 The next thing it suggested was that the likes of monounsaturated fats and polyunsaturated fats were good for us. It wasn't surprising that this study showed that these fats were the most protective of all. This is why the Mediterranean diet is constantly being encouraged as its rich in unsaturated fats such as olive oil, avocado, nuts and seeds.
4 This study encouraged us to avoid eating too many carbohydrates. Sure, haven't we all heard this before? In this study, 65pc of the 135,000 participants ate very high carbohydrate diets where over 60pc of their calorie intake was carbohydrates.
In fact, 33pc of the participants consumed diets that were over 70pc carbohydrate. Sure, we're not all endurance athletes, and even if we were, we wouldn't be having over 70pc of calories from carbs on all days of the week.
So this study showed that by overeating this food group, you're at a 28pc greater risk of dying.
5 Sticking to the carbohydrate results, the researchers noted that the people more prone to this style of diet were of lower socio-economic backgrounds and relied on the likes of white bread and white rice.
In other words, processed carbohydrates that are low in fibre.
Now, isn't it safe to say guidelines on healthy eating generally encourage limiting refined carbs and encourage the more natural varieties of wholegrains?
6 I guess what surprised many people was that saturated fat intake was shown to be protective and was even associated with lower risk of stroke. Saturated fat is the fat that's hard at room temperature and is found in the likes of animal produce (meat, dairy and eggs), palm oil and the very trendy, but over-hyped coconut oil.
If you look at the trend of research what we've learnt is that not all saturated fats are created equal. In fact the fats in milk and yoghurt have been shown by top-tier research papers to be protective against stroke. Some other scientists are pointing out that research from Harvard cohort studies are missing from this piece of research, which may have impacted the overall results as Harvard University cohort studies showed that by replacing saturated fat with polyunsaturated fat you had favourable results on risk of death.
7 The point above is precisely why the 'If It Fits Your Macros' movement is so flawed. Yes 'IIFYM' encourages the right quantity of macronutrients for your body, but it doesn't consider quality. Saturated fat isn't the same when it's found in less healthy processed food rather than in natural foods our planet provides.
8 The other issue with not considering quality of nutrients is because it focuses solely on macronutrients and doesn't consider the other ingredients within our macronutrient foods like vitamins, minerals, phytocompounds and antioxidants. Of course they would make a difference to risk of death. Sure, you'd rarely go a week without reading about vitamin D, the fat soluble vitamin. Could the micronutrients have had an impact of the results encouraging moderate amounts of fat?
9 A hint at the importance of meeting our micronutrients as well as macronutrients is found when you consider the researchers second paper from the Pure study.
They showed that 375 to 500 grams of fruits, vegetables and legumes each day lead to the lowest risk of death. A portion of fruit and vegetables is 80 grams, therefore this paper encourages us to follow the common guidance of at least five a day.
In this study raw vegetable intake was more strongly associated with a lower risk of death compared to cooked vegetable intake. This is similar to a different big review that showed salad was extremely protective against risk of death. Salad is good for us? Not too shocking.
10 What I'm surprised by is that not many people are talking about the fact that this paper showed that animal protein was inversely related to mortality or death, but plant protein had no impact. Surely this should have been picked up by more people and stimulated more discussions?
* Finally, what I'm struggling to get my head around is why anyone is pushing a diet that is consistently high or low in anything. Have we not learned anything over the years? There are four very important things to consider here.
1 Every food on the planet gives us a different array of nutrients. Unless we eat all foods, we're likely to become deficient in something.
2 Secondly, this paper isn't encouraging extremism. Take the ketogenic diet, for example. It is used by dietitians in hospitals to help treat some people with diseases such as epilepsy. It is an 80pc or even a 90pc fat diet. This paper, within its discussion, encourages 35pc fat.
3 Next up is the irritating thing... we know that every day is different and therefore our daily nutritional intake should change accordingly.
In fact, not only does it differ day to day, but is also differs depending on your ultimate goal. For example, training adaptations in sport, achieving remission in Type 2 Diabetes, maintaining remission in Type 2 Diabetes, fertility, illness, weight loss, etc... No two days are alike and there may be a guideline for overall health, but this guideline differs when applied to the individual.
4 Finally, high something leads to low something else. For example, when research wrongly suggested a low-fat diet years ago, people removed fat in their diets and replaced it with carbohydrates. This was not a healthy move. Obviously.
So can we please not learn from this? Should the focus not be on moderate amounts of everything rather than high or low anything?
In fact, the researchers' summary suggests that a diet which includes a moderate intake of fat, fruits and vegetables, and avoidance of overeating carbohydrates, is associated with lower risk of death. Sure, did we not already know this? Are we really all THAT surprised?
I don't want to sound like I'm making ground- breaking and revolutionary observations here. Even McMaster University and the researchers point out that, while this may appear surprising to some, these new results are consistent with several observational studies and randomised controlled trials conducted in Western countries during the last two decades.
ESSENTIAL FATTY ACIDS
* ALA (alpha-linolenic acid)
Omega 3 fatty acids are considered an essential fatty acid as they are necessary for human health. In order for your body to have access to them you must eat them as the body can't make them. Omega 3s come from a family of fats called polyunsaturated fatty acids. Plant sources of omega 3 called ALA are found in the likes of rapeseed oil, walnut oil, walnuts, flaxeed/ linseed or chia seeds. They are not the same as the omega 3 found in oily fish. Only a very small amount of these ALA fats can be converted to the omega 3 found in oily fish.
* EPA (Eicosapentanoic acid) and DHA (Docosahexanoic acid)
The omega 3 fats found in oily fish are called EPA and DHA. Although your body can make small amounts of them, to meet your requirements you must eat them. It's important to eat oily fish twice a week. For example salmon, sardines, mackerel, kippers and pilchards.
If you don't eat oily fish, it would be more challenging to achieve the recommended requirements. If you have a fish allergy or are vegan, an algae-based supplement may be more suitable for you. If you simply do not like oily fish, it's best to work past this for the sake of your health.
* Linoleic acid (LA)
LA is an omega-6 fat and is often the most common polyunsaturated fatty acid in the diet. Less focus needs to be paid on achieving adequate levels of this fat within most diets, and Irish people tend to eat enough.
* Other healthy fats
It's important to include a mixture of fats within the diet. For example olive oil, rapeseed oil, sesame oil, walnut oil, nuts (almonds, Brazil nuts, pecans, walnuts, macadamia, pistachio, cashew, etc...), seeds (sesame, pumpkin, chia, flax, poppy, sunflower, etc...), nut and seed butters (peanut butter, almond butter, tahini, etc...), hummus, pesto, avocado and guacamole.
* Nutrition and healthy eating isn't black and white. Generally speaking, there is no 'bad fat'. A more accurate way of explaining it would be that a person is less healthy when they don't get the balance of fats within their diet right. For example, someone may walk into my clinic and report only using coconut oil in meal preparation. The big issue here is that they are not eating a variety of fats. Each fat is chemically different, making it act differently when inside the body. Additionally, each fat has its own mixture of nutrients within it, making it special and unique.
* While it's known that we need to include some fat in our diet to remain healthy, and that we need to vary the sources of fats we eat, not all fats were created equal in terms of their positive effects on our health. Some are more beneficial and we need to eat more of them. Current research suggests other fats are less healthy and should be less of a focus in our diet.
* A good example of these are 'trans fats'. There are small amounts of naturally-occurring trans fats within our diet. For example cheese and cream, as well as beef and lamb. However, health concerns about these fatty acids have been flagged, resulting in many food companies reducing the amounts of trans fats in their products. To give you an example of this, until the 1980s margarines contained 10pc to 20pc trans fats. Due to reformulation, many margarines and spreads now have much lower trans fat content. Trans fats may also be produced when ordinary vegetable oils are heated to fry foods at very high temperatures. ΩThis is one of the reasons takeaway foods can be the less healthy choice. Additionally, foods that are produced using hardened vegetable oils typically contain some trans fats.
* This is another reason why biscuits, pies, cakes and fried foods are less healthy. To check the packet to see if the product contains trans fats, begin by looking at the ingredients.
* A fully hydrogenated fat does not contain trans fat; only partially hydrogenated fat does. If a food product contains partially hydrogenated fats or oils, it will almost certainly contain trans fats too, and the higher up the list the fat or oil appears, the more trans fats the product is likely to contain.
Food swaps - how to add healthy fats
There is no such thing as a 'bad fat'
• Breakfast: porridge made with oats, low-fat milk, banana & cinnamon
TIP: Add less oats but use regular milk and add pecans.
• Snack: Large apple Tip: Choose a smaller apple but smear with peanut butter
• Lunch: Sandwich with brown bread, spinach, tomatoes, chicken breast
TIP: Why not have an open sandwich and swap a slice of bread for some avocado?
• Snack: Low-fat flavoured yoghurt
TIP: Opt for a natural yoghurt with a sprinkle of seeds
• Dinner: Chicken stir fry with rice
Tip: Why not eat less rice but add some cashews?
Health & Living