Sunday 20 January 2019

The truth about fats: What to avoid and what to eat in moderation

Recent research has rehabilitated the reputation of fats, but that does not mean we can indulge with abandon. Our resident dietitian Orla Walsh is here to address common myths about the dietary staple

Image: Getty
Image: Getty
Cocount Oil is all the rage at the moment
Orla Walsh
Peanut butter should be eaten in moderation

When it comes to eating healthy, fats get a bad rap - but not all fats are unhealthy and some may even help to promote good health - it's knowing which fats to avoid, and which to eat in moderation that can help you lead a healthier lifestyle.

Myth? Coconut oil is healthier than other fats

Undecided. There is not enough evidence to back up this statement.

Fats are carbon chains classified by how long they are and how they're attached together. There are two types of fats:

1. Medium-chain fatty acids (MCFAs) which are shorter in length (6-12 carbons long).

2. Long-chain fatty acids (LCFAs) which are longer in length (12+ carbons).

MCFAs and LCFAs behave very differently in the body. Shorter MCFAs are easily absorbed into the body. They also have direct access to where they want to go in the body. The LCFAs are longer and need to be chopped up into smaller bits. They then need to be packaged up into a parcel of sorts to be transported around the body. Both MCFAs and LCFAs want to go to the liver to be broken down or used. MCFAs have a shortcut to the liver while LCFAs have to go the long way. The problem with going the long way is that they can get side-tracked en-route and deposit themselves elsewhere in the body. This may cause the body harm over time.

Most of the health benefits attributed to coconut oil are associated with its high content of MCFAs. However a lot of the research is on MCFAs that are 8 or 10 carbons in length while most of the MCFAs in coconut oil have 12 carbons. So they're chemically different. If something is chemically different, it will act differently in the body. It's like comparing apples to pears!

So if it's mostly made up of 12 carbons, it won't act the same as the fats made up of 8-10 carbons. Most of the 8-10 carbon MCFAs (95pc) get direct access to the liver. Reports suggest only about 25-50pc of the 12C MCFAs go straight to the liver. Therefore we can't assume it has the same health benefits.

Myth? Extra Virgin Olive Oil is better than Olive Oil

True! The main difference between Extra Virgin olive oil and other olive oils is simply how the oil is extracted from the olives. Olive oil, such as the likes of 'light olive oil', may be extracted using chemicals and heat. Extra Virgin olive oil is the juice that has been squeezed directly out of the olive fruit, comparable to fresh fruit juice versus juice from concentrate. And just like the best oranges produce the best OJ, the better quality olives produce the better olive oil, so there are differences between brands.

Nevertheless, for this reason, Extra Virgin olive oil and olive oil do not boast the same health benefits and olive oils don't provide the distinct flavour you associate with Extra Virgin olive oil. Cold pressed on the day of harvest usually suggests better quality oil.

Make sure to follow the 'best before' date as olive oil has a shelf life of about one year after production. Once you open it, try and use it within the month, and store away from heat and damp. You may need to buy smaller bottles to prevent waste.

Cocount Oil is all the rage at the moment

Myth? You should never cook with olive oil

False! You can cook with it, but the 'smoke point' different between oils. This is similar across all oils. No two oils act the same when it comes to cooking. At different cooking temperatures they all begin to change. The temperature they begin to change at is different between oils and among oils. Oil's have different heats at which they start to smoke and break down, called their 'smoke point'. If you notice your oil appearing to smoke, discard it as both the nutritional value and taste may have changed.

The likes of peanut and sesame oils are great to use when cooking stir fries as they're more stable at the high temperature needed for frying and add a lovely taste. Vegetable oils also have a higher smoking point. The likes of flaxseed and walnut oil have low smoke points and are great for salads.

According to a study from 2012, the stability of avocado oil appeared similar to olive oil. It's difficult to ascertain the exact smoking point of olive oil as it appears that the more refined it is, the higher the smoking point. Therefore the chemical composition of the olive oil, particularly the amount of natural antioxidants, help predict its behaviour when heated. However a study comparing the different types of olive oil showed that, despite the category of olive oil tested, it was resistant to frying conditions. While another study concluded that despite the heating conditions, virgin olive oil maintained most of its minor compounds and, therefore, most of its nutritional properties.

Myth? Peanut butter is good for you and you can eat as much as you want

Peanut butter should be eaten in moderation

I wish!! Unfortunately it's false. It's great for you, and unless allergic, you should enjoy it. However you need to be mindful of portion size (1tbsp is a portion for most of us... ahem...)!

Nuts are indeed great for you and something you should be having daily. In one study, researchers tracked 76,464 female and 42,498 male subjects. Those who ate 30g of nuts per day, including peanuts and tree nuts, not only had a lower risk of death than those who ate nuts less than once per week, they were also leaner - less fat on their body. They had a smaller waist circumference and decreased risk of obesity.

Nuts aren't calorie free though. Peanuts contain roughly 14g of fat and 170kcal per 30g serving. The fat in peanuts is primarily heart-healthy mono-unsaturated and polyun-saturated fats. They're also a delicious way for people to eat other heart-healthy nutrients such as vitamin E, potassium, L-arginine, phytosterols and resveratrol. Peanuts and almonds contain more protein per serving that the other nuts. Generally nuts contain 2-4g of protein per 30g serve while peanuts and almonds contain about 7g. Therefore peanut and almond butter are a great choice for your wholegrain toast in the morning time or as the basis of protein balls!

Myth? Low fat milk is healthier than full fat milk

false! Whole milk contains 3.5g of fat per 100ml. Just because there is a low fat version available, does not mean that milk is high fat! Any drink with less than 1.5g fat per 100ml is low fat. Milk is a far cry from being high fat, and is actually closer to being naturally low fat. There's approx 2.5g more fat per 100ml of full fat milk compared to low fat. Typically, if you have porridge in the morning and perhaps a cappuccino mid afternoon, this is only saving about 10g of fat per day, equivalent the amount of butter you put on one slice of bread. If you're looking to lower your overall fat intake, you would make bigger changes by choosing different cuts of meat (breast, loin, more fish, more plant proteins), measuring oil in cooking (1 to 2 tsp of oil) and through alternative cooking methods (grilling, boiling, baking).

A systematic review of the literature, published in 2016, looked at milk consumption, mortality, coronary heart disease and stroke. They found no evidence for a decreased or increased risk of mortality, coronary heart disease, and stroke associated with milk consumption. A similar review, but published in 2015, showed the same thing. So enjoy milk, and by all means choose the normal one over the slightly lower fat one, if you prefer it.

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