Two common food myths have hit the headlines today. Firstly, a study has suggested that using vegetable oils in preference to much-maligned butter could be damaging, rather than beneficial to health, and actually be a cause of obesity. And secondly, a scientist has announced that it's perfectly safe to eat certain types of food that have fallen on the floor. Professor Anthony Hilton argues that as long as the food only makes contact with the floor for a short amount of time, and is not "obviously contaminated", it's unlikely to be harmful.
This second nugget of wisdom is contrary to official NHS guidelines, but excellent news for the 79pc of us who have used the five second rule as an excuse to eat food that has missed the plate, or our mouths. Yes, it seems we really do remain students even after we've graduated.
The 3, 5 or 10 second rule (depending on who you ask) is just one of many popular myths surrounding food. But which are true? And which need to be debunked?
1. Raw food is better than cooked
Proponents of the raw food diet insist that it's better for you because cooking destroys enzymes that make food easier to digest. They also insist that cooking reduces the nutritional content of food, such as Vitamin C.
While both of these things are technically true, neither of them are necessarily enough to make raw food "healthier" than cooked. Firstly, your body destroys these enzymes anyway once they reach the stomach, thanks to gastric acid. Secondly, cooking food can add to its nutritional value, by breaking down undigestible cellulose fibre. Both tomatoes and carrots are more nutritious in cooked form.
Of course, there are caveats here. Overcook food and it's nutrition becomes dubious – hence the worry about carcinogens in toast and roast potatoes. Equally, raw food can be dangerous: though raw milk and butter have gained popularity in recent years, they can also make you extremely ill, and may contain bacteria such as salmonella, E. Coli and listeria. Pasteurisation was invented for a reason!
2. You can't reheat rice
The NHS is plain about this: you shouldn't reheat rice because it can cause a nasty type of food poisoning due to the presence of spores called Bacillus cereus. What we tend to forget, however, is that that only if the reheating isn't done correctly.
Ideally, all cooked rice should be eaten immediately. However, if leftovers are cooled quickly (within one hour) and stored in the fridge, they are safe to eat the next day. Just ensure that the rice is piping hot when you reheat it.
3. Chewing gum takes seven years to pass through a human body
The famous urban myth argues that inadvertently swallowed gum will take seven years to pass through the gut. While chewing gum does contains ingredients that are indigestible, this does not mean that it will linger in the stomach for years. The natural motion of the digestive system will simply move it through the body at roughly the same pace as everything else you've eaten, to ultimately be excreted.
Not that swallowing gum should be in any way encouraged.
4. Microwaving food destroys its nutritional content
The term "radiation" frightens people, and it's a common misconception that cooking food in the microwave can be damaging to our health.
While the waves of energy used to heat food in the microwave are similar to other, more dangerous types, the point is that they are much, much shorter, and only target certain molecules, such as water. The energy from the waves causes the molecules to vibrate, therefore generating heat and cooking the food.
Harvard Medical School points out that using a microwave to cook food can actually be beneficial, as cooking times are shorter and less water is needed, allowing foods such as broccoli to maintain more of their nutritional value than if they'd been boiled.
5. Hair of the dog
People have insisted since the 16th century that the best way to cure a hangover is by having another alcoholic drink. It is thought that by giving your body the alcohol it craves (via a Bloody Mary first thing, say), you will be able to offset the nausea, sweating and splitting headache associated with a hangover.
Unfortunately, there is no concrete scientific evidence to suggest that this is the case. Nor any other supposed hangover cure, apart from using an intravenous drip to rehydrate your body.
6. Washing chicken removes bacteria
Recent studies have shown that the majority of British supermarket chickens contain traces of the bacteria campylobacter, the most common form of food poisoning. Some people believe that washing chicken before cooking can help to remove this bacteria, but the Food Standards Agency (FSA) warns that this is potentially more dangerous, as germs can be spread onto hands, work surfaces and clothing.
As long as you are careful to wash your hands, surfaces and equipment that have been in contact with raw chicken and ensure that the meat is cooked thoroughly, you should destroy any harmful bacteria.
7. You can't refreeze frozen food
Good news for anyone trying to cut down on food waste: it is perfectly safe to refreeze food that has previously been frozen and properly thawed. However, the NHS discourages the re-freezing of thawed fish and meat that hasn't been cooked. Best to cook them and refreeze afterwards - just ensure that they are properly cool before putting them in the freezer.
8. You shouldn't eat too many eggs
In the past, we were told not too eat too many eggs due to fears about high levels of cholesterol. However, the British Heart Foundation dropped its advice to limit consumption to three eggs a week in 2007, and scientists argue that the impact on cholesterol is "insignificant". In fact, eggs have multiple health benefits: the yolks are a good source of protein and fat, while the whites contain selenium, vitamin D, B6, B12 and minerals such as zinc, iron and copper.
9. Detoxes are good for you
Every January we are besieged by new diets (usually involving juice, soup or nothing at all) that claim to "detoxify" the body by removing dangerous substances building up the body. Unless you happen to have mislaid your liver, you'll be relieved to hear that your body is already doing this, and doing it rather well. Your internal organs use chemical reactions to convert dangerous substances into safe ones that are naturally excreted.
Restricting yourself to a liquid diet could actually do more harm than good: juices lack the essential fibre of whole fruits and vegetables, and you could be denying yourself essential proteins and minerals.
10. Brown eggs are better than white
The eggs found in most British supermarkets are generally a pine brown colour, but occasionally (particularly in mixed egg selections) you come across white ones. It used to be the other way around, but white eggs were fazed out in the 1970s over the misconception that brown ones were more nutritious.
It turns out that the colour of an eggshell is a question of genetics, not nutritional value. Brown and white eggs have the same amount of protein, and there's no noticeable difference in flavour.
11. Saturated fat is bad for you
The almost universally upheld belief that a low-fat diet is the secret to good health and weightloss has recently been targeted by the health industry. A 2016 report by the National Obesity Forum argued that the previous guidelines were based on "flawed science" and that a diet higher in fat is beneficial.
No link has been found between a diet high in saturated fat and heart disease, and the government is reviewing its guidelines on the consumption of saturated fats, such as those in butter and cheese, after claims that fatty foods have been wrongly “demonised”.
No one is suggesting that a Big Mac a day will pave the way to health, but it does mean that there is no need to villify all dairy that's not cottage cheese.
12. Feed a cold, starve a fever
This famous saying is probably based on the fact that people with a fever tend not to feel hungry, and may take it as an indication that food is best avoided. While anyone with a stomach bug may want to keep away from large meals, it's important not to deny yourself food simply because you have a temperature. It is vitally important to keep yourself hydrated when ill, and your body needs the nutrients from food in order to have a fully-functioning immune system that can keep the bugs at bay.
13. Frozen food isn't as nutritious as fresh
There are plenty of myths surrounding frozen food, with one of the most popular being that it is less nutritious than fresh produce. This is now held to be false, and the opposite may in fact be true. Frozen fruits and vegetables are often frozen at the point of harvest (or very soon after) meaning that they preserve many of their nutrients. Conversely, "fresh" foods may have been in storage for days or even weeks before they make it to the supermarket shelves.
14. Natural sugar is better than refined sugar
The clean-eating brigade may tout a myriad of options to get you away from the infamous white stuff, whether that be rice malt syrup, agave syrup, maple syrup or dates. As unrefined and "natural" as these sugars may be, the cold hard truth is that they are ultimately no better for you, even if they contain tiny amounts of micronutrients. Sugar is sugar: they all contain sucrose, glucose and fructose, and your body processes them in the same way. Sorry.
15. Gluten-free food is automatically healthy
Another popular fad, the UK has seen a boom in gluten-free products hitting shelves in recent years. This is great news for the 1pc of Brits who suffer from coeliac disease and gluten sensitivity, for whom wheat products can cause extremely unpleasant, and even dangerous, symptoms.
Despite numerous bloggers touting going wheat-free as the secret to healthy living, the truth is that cutting out all gluten is unlikely to make you healthier. A gluten-free cake is still cake, and may be even unhealthier than one containing gluten, as creating gluten-free baked goods can require extra ingredients and processing to resemble their wheaten counterparts, resulting in higher levels of sugar and fat.
Of course, if you do suffer from a gluten sensitivity, please ignore the above.