This article was written by one of The Food Medic team; registered dietitian Maeve Hanan.
It’s no surprise that many people are confused about how to eat well with the amount of nutri-nonsense we’re exposed to. Here are the top 9 diet myths to free yourself from in 2022.
#1: Carbs cause weight gain
This message is massively over-simplified and often fuels the fear of carbohydrates that so many people experience. There is nothing inherently wrong with carbs. It is calories, not carbs that lead to weight gain.
One of the reasons that carbohydrates are often targeted for weight loss purposes, is that short-term weight loss can occur after reducing carbohydrate intake, but this is usually related to a loss of water from the body and due to a change in calorie intake (less energy in and more energy out) due to overall diet and lifestyle changes. This weight loss isn’t sustainable for most people, especially if the diet is extreme. If you are interested in reading about the limitations of weight-loss diets in general, check out this article. Carbohydrates also play a central role in a balanced diet by being the body’s preferred source of fuel. While many of us could do with reducing the amount of free sugars in our diet, many carbohydrate-containing foods are very nutritious, including high-fibre foods like wholegrains, fruit and vegetables. So let’s stop all the carb hate!
#2: Training fasted is better
Fasted training is promoted as a way of burning more fat for fuel and less carbohydrate in order to burn body fat and/or maximise training outcomes. Although the body can switch fuel sources when carbohydrate (the preferred fuel source) isn’t available, it’s unclear whether this results in performance improvements and can actually worsen performance in some cases due to fatigue, hunger, headaches etc. (1, 2). Also, a reduction in body fat doesn’t occur straight after one fasted workout, as a sustained energy deficit is needed. Fasted training can also place stress on the body which over time can contribute to a higher risk of injuries, a weakened immune system, hormonal disturbances and more (3). Active women are particularly at risk of hormonal issues, such as irregular periods or a loss of periods, when there is not enough energy available (3, 4). Therefore, it’s recommended to avoid high intensity exercise that lasts longer than 60 minutes while fasting, and this is usually recommended no more than twice per week (1, 5).
#3: Unrefined sugars are better than refined sugars
‘Unrefined sugar’ usually refers to foods like honey, agave nectar, maple syrup and coconut sugar that contain naturally-occuring sugar, rather than processed sugar. But this isn’t a term that scientists and nutrition professionals use because these sources of ‘unrefined sugar’ act in a very similar way to refined sugars in the body. These foods can contain some extra minerals, but the amounts are usually insignificant. Instead of focusing on ‘unrefined sugars’, the UK public health advice for those aged 11 or older is to limit the intake of free sugars to 30g (or 7 sugar cubes) per day (6). Free sugars are “added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and unsweetened fruit juices” (7). For more information about unrefined sugar check out this article. And for information on finding the balance with sugar check out this article.
#4: Certain foods help you burn fat
‘Fat-burners’ are promoted to reduce fat absorption or increase metabolic rate or burn more fat during exercise. Common ‘fat-burners’ include: spicy food, caffeine, green tea extract and supplements containing a central nervous system stimulant called ephedrine. These are either unlikely to have a significant impact on body fat, or if they do they can be harmful. For example, chilli and green tea extract may increase metabolic rate slightly, but more research is needed and it isn’t clear if this leads to a reduction in body fat (8, 9, 10). High doses of caffeine and green tea extract can have negative side effects, and although there is a small amount of evidence that the stimulant ephedrine may be linked with weight loss, there are also a number of safety concerns and cases of heart attacks, psychotic episodes and even death have been reported (11). See here for more information about so-called ‘fat burners’.
#5: Protein is bad for your kidneys
Protein plays a number of vital roles within our body, including muscle growth and repair and maintaining bone health. The recommended intake of protein in the UK for the general population is 0.75g per kg per day, and for those who exercise regularly this is usually between 1.4-2g of protein per kg (12, 13). Interestingly, some research has found that exceeding these recommended amounts has not been seen to be harmful for kidney health. For example, consuming upto 4.4g of protein per kg per day for 8 weeks had no harmful effects on the kidneys of adults who strength train (14). Another study found no adverse effect from consuming 2.5g of protein per kg body weight per day for a year (15). However, there are medical exceptions to this, such as certain cases of liver or kidney disease when a low protein diet may be advised under medical and dietetic supervision.
#6: Gluten-Containing Foods Are Bad for You
Gluten is a protein found in wheat, rye and barley. There is no need to avoid gluten unless you have a medical reason to do so, such as coeliac disease which is an autoimmune condition where the immune system attacks tissues in the small intestine in response to gluten. Those who have non-coeliac gluten or wheat sensitivity (NCGS) may also need to avoid gluten, although this condition is currently less well understood than celiac disease (see here for more information about NCGS). Otherwise, unnecessarily avoiding gluten can do more harm than good as it is found in a number of nutritious staple foods, like bread, pasta and cereals. Wholegrain versions of these foods are an important source of fibre, B-vitamins and certain minerals, and refined (or white) bread and flour in the UK is fortified with calcium, iron, thiamine and niacin and will soon be fortified with folic acid as well (16). Studies have also found that avoiding gluten can lead to a higher intake of fat and salt, and tends to be more expensive (17, 18). Unnecessarily cutting out foods can also be tedious and damaging to our relationship with food.
#7: Fresh fruit and veg is better than frozen
Frozen fruit and vegetables can actually contain more nutrients than fresh versions as they are frozen soon after harvesting which protects the nutrients. This means you are getting the goodness of the food at the time it was picked. Whereas, with fresh versions vitamin levels can begin to reduce while it is stored, transported and sitting in the shop. A study from 2017 found that although people tend to think that fresh produce is more nutritious, frozen produce is either as nutritious or more nutritious when the nutrient content was analysed (19). Frozen food also has the added bonuses of being more affordable, convenient and can help with reducing food waste. For more information about frozen fruit and vegetables, check out this article.
#8: Artificial sweeteners cause cancer
Although there is a lot of fear-mongering about artificial sweeteners like aspartame and saccharin, any food additives like this are thoroughly safety tested before they can be sold or used in products in the UK (20). Most of the confusion about sweeteners and cancer came from studies in the 1970s when rats developed bladder cancer in response to high doses of sweeteners (21, 22). But since then it has been found that this research doesn’t apply to humans. Cancer Research UK state that “the best evidence shows that artificial sweeteners, like aspartame, do not increase the risk of cancer” (23). Check out this article for more information about artificial sweeteners.
#9: Detox diets rid the body of toxins
Detox diets are absolute nonsense! Unless you are severely unwell the body does a great job of detoxifying itself, using our kidneys, liver, lungs, gut and skin to remove waste and toxins. For example, the liver processes and removes toxins from alcohol or drugs, the kidneys remove waste products like urea in urine and the gut removes harmful substances from the body in vomit or diarrhoea. Most so-called ‘detox diets’ like fasting detoxes and juice ‘cleanses’ are restrictive, nutritionally-unbalanced and extreme. Not to mention that ‘detox’ teas and supplements are laxatives in disguise! So save yourself from these faddy diets in 2022. If you are interested in improving your nutritional intake, check out these top tips for eating well.
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