An interesting feature of the past decade has been the persistent popularity of certain theories on nutrition, even though they’ve been well established as myths. Here’s a selection of the ones we still come across.

Myths of the past decade

Margarine is one molecule away from plastic

This statement is somehow meant to prove that margarine-type spreads are not fit for human consumption. However, the reality is margarine has a much closer molecular composition to butter than it does to plastic. Choose the fat you prefer, depending on the context of your whole diet (see our feature Chewing the fat for more), but don’t worry about this bit of pseudoscience.

Homogenisation of milk is harmful

There are lots of myths about milk, including that we are not ‘designed’ to drink milk. While people with lactose intolerance can only tolerate a small amount of milk, for the rest of us milk is a good food and a useful source of protein and calcium. When it comes to homogenisation, although this might sound scary, there’s no evidence it’s harmful. If you’re still worried, just choose trim milk, which isn’t homogenised.

Microwaves are unhealthy

This one still persists, despite the fact that microwaves have been in our kitchens for more than 40 years. There is no evidence of any harm from consuming microwaved food — when the oven is used properly. Microwaves can’t escape from an undamaged microwave oven and microwaving doesn’t make our food radioactive. It is possible to overheat food in a microwave, causing explosions, smoke or burns, but that can happen with other cooking appliances too. And we need to be careful with plastic wrap. Don’t let it touch the food and avoid containers that aren’t microwave-proof. But in general, a microwave is a useful kitchen appliance and there’s evidence microwaved vegetables retain more of their vitamins and antioxidants than boiled ones.

Food combining and blood types

There’s nothing like a science-ish sounding theory to sell a diet book. Food combining (the idea that different food groups should not be eaten together) and the blood type diet (we should eat differently depending on our blood type) are a couple of the more long-lived bogus diet theories. For the record, most foods are already a combination of nutrients and there’s no evidence eating them separately achieves anything. Likewise there’s no evidence that just because you have a certain blood type, you need to eat a specific diet, either.

Going gluten free is a good way to lose weight

Gluten-free diets are growing in popularity as more people are diagnosed with coeliac disease and gluten intolerance. However, there’s a trend to adopt a gluten-free diet as a weight loss tool. This may be effective — if you’re eating mostly fresh whole foods — but it can easily backfire if by switching to a gluten-free diet you add lots of processed gluten-free food. We’ve found many examples of pretty unhealthy gluten-free foods; don’t assume those words mean a product is healthier or lower in kilojoules.

Hormones in chicken

It’s surprising how many people still think there are hormones in our chicken. This may be because they are used in other countries. There’s no evidence growth hormones or steroids were ever used in New Zealand and their use has been specifically banned for more than 30 years. So that’s a myth we can retire!

Six small meals a day

This is often cited as useful advice for losing weight and it may well work, so long as the meals really are small. The danger with this is that you may end up over-eating. The bottom line? Eat when it suits you and try not to worry about diet rules!

Apple cider vinegar cures… everything!

This has been around forever — there are books dedicated to the health benefits of this apparently wondrous liquid. While there is some evidence around vinegar (of any type) helping to lower the GI of meals and therefore being beneficial in reducing blood glucose levels, other specific apple cider vinegar research has had mixed results. Enjoy it in your salad dressing, but don’t think of it as a cure-all.

A snapshot of modern myths

Bone broth can cure disease

This glorified stock is delicious, and it certainly won’t hurt you. But it’s not a magic food.

Raw diets are better than cooked

Lots of raw foods are great for us – we should all be eating fresh, raw salads frequently. But a completely raw diet is hard work, and could result in you being short of some nutrients, if you’re not careful.

Grains are evil and we shouldn’t eat them

If you’ve got coeliac disease you’ll have to stay away from some specific grains. But for most of us, whole grains are important and useful in our diets, not to mention delicious!