10 common food myths about everyday diets and nutrition

• Neil Perry's fried eggs with nahm jim recipe

There's no shortage out there of information to answer any diet- or nutrition-related queries we may have. In fact, there are countless different sources telling us what we should, and should not, be eating.

The issue is some of the material we come across via social media, or family and friends, is not always accurate.

Worse, some of these ideas become beliefs that perpetuate false notions related to diet, nutrition and weight loss.

Here are some common nutrition myths we should put to rest, once and for all.

Eggs increase cholesterol

Possibly the most common question that is asked in relation to nutrition is about egg consumption, and whether eggs increase blood cholesterol levels. For many years, health professionals encouraged patients to limit egg consumption if they had, or were at risk of high cholesterol levels but more recently many intervention studies have shown that eggs, when eaten in their natural form, do not adversely affect blood cholesterol levels. Specifically, it has been shown that it is the positive fat profile in eggs that appears to be protective of any negative effect on blood cholesterol levels overall. In practical terms, this means that if the rest of your diet is healthy overall, you can enjoy an egg or two each day without any cause for concern, even if you're keeping an eye on your cholesterol levels.

Skim milk has more sugar than full-cream milk

It is often argued that skim milk is more processed than full-cream milk, and that skim milk contains more sugar, which is not the case. Rather, full-cream milk actually has slightly more lactose, which is the sugar found naturally in dairy. Public health recommendations to swap to reduced-fat or low-fat (skim) milk were based on the fact that Australians consume too much saturated fat in their diet overall. So swapping to a lower-fat milk helps to reduce saturated fat intake overall, and contrary to popular belief does not result in more sugar being consumed.

Fruit is high in sugar so should be avoided

While fruit does contain the naturally occurring sugar fructose, it also has plenty of fibre and key nutrients. Overall, a couple of pieces of fruit a day adds relatively small amounts of natural sugars to the diet. Fruit-based snacks, juices and dried fruit on the other hand are all concentrated sources of fruit sugar and as such can be easily overconsumed, so it's not surprising they have been linked to long-term weight gain. Here, it is an excessive energy intake, not fructose intake specifically, that is associated with weight gain. It's also important to remember that the Australian food supply is not a rich source of high-fructose corn syrup, unlike in the US and other countries. It is this form of fructose that is closely associated with weight gain and type 2 diabetes, not naturally occurring fructose in whole, natural foods such as fresh fruit.

You should never cook with extra virgin olive oil

This is completely false, especially in relation to good quality, Australian extra virgin olive oil, which has an extremely high antioxidant content that helps to protect it from molecular damage when it is heated. This means that you can use extra virgin olive oil for baking and roasting, as well as a dressing or dipping sauce. Keep in mind though that some olive oils are blends, which will not respond to heat as well as Australian extra virgin olive oil.

Nut mylk is milk

The growth of plant based "mylk" in Australia has exploded but a key thing to know is that plant milk, and nut- and oat-based mylks in particular, are not actually milk. Milk must come from the mammary glands of an animal, and milk will naturally contain a large number of nutrients including protein, calcium, magnesium and phosphorus. Nut versions of milk contain very few of these nutrients naturally, and even when fortified with calcium and vitamin B12 are still exceptionally low in protein. This is not to say you shouldn't enjoy plant-based varieties of "mylk", but keep in mind that it is not milk in a traditional sense.

Potatoes are fattening

The poor old potato. This age-old food staple is packed with B group vitamins and fibre and yet was banned from many weight-loss diets. If you consider that a single potato contains just 20 grams of total carbohydrates, which is less than half a cup of rice or pasta, a simple baked potato (of reasonable size and not made into chips) is a great choice nutritionally.

Raw vegetables are better than cooked ones

While some raw vegetables can be extremely good for us (think leafy greens, whose key nutrients are sensitive to heat), this is not always the case. In fact, some of the nutrients we find in vegetables actually become more concentrated and bioavailable when they are cooked. For example, the beta carotene content of carrots increases when carrots are cooked, as does the lycopene content of tomatoes. On the other hand, leafy green vegetables can have some of their key nutrients destroyed when exposed to high temperatures so these are best consumed raw or lightly cooked. This means that to help support optimal nutrient we should include both raw and cooked vegies in our daily diet.

Margarine is a healthier choice than butter

Back in the 80s and 90s we were regularly told that plant-based, vegetable oils were much better for us than butter, which was a source of saturated fat. Now we know that processed vegetable oils, including those used to make margarine are not overly good for us, and add more omega-6 fats in our diets. Omega-6 fats act to drown out the anti-inflammatory omega-3 fats, especially when consumed in high amounts via processed and packaged foods. This is not to say that butter is overly good for us, rather that margarine is definitely not better nutritionally.

Frozen foods are less nutritious than fresh

New technological advances mean that much of the frozen fresh foods and meals we find at supermarkets are frozen immediately after cooking or harvest, and as such retain all if not more nutrients than foods that have not been stored correctly, or consumed some time after preparation. This means you can enjoy frozen vegies, fruits and even healthy meals without worrying about the nutritional quality of the meal.

Coconut oil is healthy

Coconut oil, like all fats, contains 5 grams of total fat per teaspoon, 90 per cent of which is saturated. The main reason that coconut oil is sprouted for its health benefits is that a significant proportion of the fat type in coconut oil is lauric acid, a type of fat known to increase "good cholesterol" in the bloodstream and a medium-chain triglyceride, which is more likely to be burnt as energy than other fats. While this may sound appealing, the truth is that coconut oil is still a fat, high in energy with few if any other nutrients, which does not make it a "healthy" choice by any standards.

Susie Burrell is a nutritionist and dietitian.