20 mainstream nutrition myths scientifically disproved
Mainstream nutrition is full of nonsense. Despite clear advances in the field of nutritional science, the old myths seem to persist. Here are 20 nutrition myths that have been debunked by scientific research.
Myth 1: The healthiest diet is a low-fat, high-carbohydrate diet with lots of cereal products
A few decades ago, the entire population was advised to eat a low-fat, high-carbohydrate diet. But at that time, not one study had shown that this type of diet could actually prevent disease.
Since then, many high-quality studies have been conducted, including the Women's Health Initiative - the largest nutrition study in history.
The results were very clear... this type of diet does not cause fat loss, cannot prevent cancer or reduce the risk of heart disease (1, 2, 3).
Myth 2: Salt consumption should be limited to lower blood pressure and reduce the risk of heart attack and stroke
The salt myth is still very much alive, even though there has never been good scientific research to support it. Although reducing salt intake can lower blood pressure by an average of 1-5 mm/Hg, it has no effect on the incidence of heart attacks and strokes or the risk of death (4, 5).
Of course, you may be an exception to this if you have a condition such as salt-sensitive hypertension (6). However, the public recommendation that everyone should reduce their salt intake (and eat boring and tasteless food) is not based on scientific fact.
Myth 3: It's best to eat many small meals throughout the day to "keep the metabolic flame burning."
It is often claimed that you should eat many small meals throughout the day to keep your metabolic rate high.
However, scientific studies clearly contradict this. Eating 2 to 3 meals a day has exactly the same effect on the amount of calories burned per day as eating 5 to 6 (or more) smaller meals (7, 8).
Eating many small meals might be beneficial for some people (e.g. to prevent excessive hunger), but it is incorrect that the number of meals we eat affects the amount of calories we burn.
There are even studies that show that eating too often can be harmful. A recent study showed that eating more frequent meals on a high-calorie diet can dramatically increase the amount of liver and abdominal fat (9).
Myth 4: Egg yolks should be avoided as they are high in cholesterol, which promotes heart disease
We have been advised that we should reduce our consumption of whole eggs because egg yolks are rich in cholesterol. However, dietary cholesterol has a surprisingly small effect on blood cholesterol levels - at least for the vast majority of people (10). Studies have shown that eggs increase levels of the "good" HDL cholesterol and do not increase the risk of heart disease (11).
A review of 17 studies with a total of 263,938 participants showed that the consumption of eggs has no effect on the risk of heart attack or stroke in non-diabetic individuals (12). However, it should be kept in mind that some studies have observed an increased risk of heart attack in diabetics who ate eggs (13).
Whole eggs are one of the most nutrient dense foods and almost all nutrients are found in the yolk. So telling people to throw away egg yolks is perhaps the most nonsensical advice in the history of nutrition.
Myth 5: Whole wheat is a health food and an essential part of a balanced diet
Wheat has long been a part of the human diet, but this changed due to genetic manipulation in the 1960s. The "new" wheat is significantly lower in nutrients than older varieties (14).
Preliminary studies have shown that modern wheat may increase cholesterol levels and inflammatory markers compared to older wheat varieties (15). It can also cause symptoms such as pain, bloating, fatigue and reduced quality of life in people with irritable bowel syndrome (16).
While some older varieties such as einkorn and kamut may be relatively healthy, modern wheat is not.
In addition, it should be remembered that labeling as "whole grain" is often a pure joke. These grains have usually been pulverized into a very fine flour that has similar metabolic effects to white flour.
Myth 6: Saturated fats increase LDL cholesterol levels in the blood and the risk of a heart attack
For decades we have been told that saturated fats increase cholesterol levels and cause heart disease. In fact, this view is one of the cornerstones of modern dietary guidelines.
However, several recent large-scale study reviews have shown that saturated fats are not associated with an increased risk of dying from heart disease or stroke (17, 18).
The truth is that saturated fats increase the levels of good HDL cholesterol and change the size of LDL cholesterol particles from small to large, which is associated with a reduced risk (24).
For most people, eating saturated fats in reasonable amounts is perfectly safe and even healthy.
Myth 7: Coffee is unhealthy and should be avoided
Coffee has long been considered unhealthy, mainly due to its caffeine content. However, most studies show that coffee has clear health benefits.
This could be related to the fact that coffee is one of the best sources of antioxidants in the Western diet, outperforming both fruit and vegetables in this respect (20).
Coffee drinkers have a lower risk of depression, type 2 diabetes, Alzheimer's and Parkinson's disease and studies even show that they live longer than people who don't drink coffee (21, 22).
Myth 8: Eating fat will make you fat. So if you want to lose weight, you need to eat less fat
Fat is the stuff under our skin that makes us look soft and flabby. For this reason, it only seems logical that eating fat would make us even fatter.
However, this depends entirely on the context. Diets that are high in fat and carbohydrates can make you fat, but it's not the fat that makes you fat. In fact, diets that are high in fat but low in carbohydrates consistently lead to greater weight loss than low-fat diets - even when the low-fat diet group reduces calories (23).
Myth 9: A high-protein diet increases the burden on the kidneys and the risk of kidney disease
It is often claimed that protein puts a strain on the kidneys and increases the risk of kidney failure. However, even if it is true that people with existing kidney disease should reduce their protein intake, this does not apply to healthy people.
Numerous studies, including those conducted on athletes who eat large amounts of protein, show that a high-protein diet is completely safe (24).
A higher protein intake can even lower blood pressure and help fight type 2 diabetes - which are two of the main risk factors for kidney failure (25, 26).
It's also important to remember that protein reduces appetite and supports weight loss - and obesity is another strong risk factor for kidney failure.
Myth 10: Full-fat dairy products are high in saturated fat and calories and increase the risk of heart disease and obesity
High-fat dairy products are among the richest sources of saturated fat and are very high in calories. For this reason, we have always been told that we should eat low-fat dairy products instead.
However, studies do not support this. Eating full-fat dairy products is not associated with an increased risk of heart attack and is even associated with a lower risk of obesity (27).
In countries where cows are grass-fed, the consumption of full-fat dairy products is even associated with a 69% lower risk of heart disease (28).
The primary benefits of dairy products are based in part on their fat content, which is why choosing low-fat dairy products is a bad idea.
Of course, this doesn't mean you should go completely overboard and add massive amounts of butter to your coffee, but it does imply that reasonable amounts of full-fat dairy products from grass-fed cows are safe and healthy.
Myth 11: All calories are the same and it doesn't matter what type of food they come from
It is simply false that all calories are the same. Different foods go through different metabolic pathways and have different influences on fat burning, hormones and the areas of the brain that regulate appetite (29).
A high-protein diet, for example, can increase the metabolic rate by 80 to 100 kcal per day and significantly reduce appetite (30). In one study, such a diet resulted in subjects automatically eating 411 kcal less per day and also losing 11 pounds in 12 weeks - just by adding more protein to their diet (31).
There are many other examples of how different foods have very different effects on hunger, hormones and health - because a calorie is not a calorie.
Myth 12: Low-fat foods are healthy because they are lower in calories and saturated fat
When the low-fat diet guidelines came out, food manufacturers responded with all kinds of "health foods". The problem is that these foods taste terrible when the fat is removed, so food manufacturers added large amounts of sugar.
However, the truth is that excess sugar is very harmful, whereas this is not true for the fat naturally occurring in foods (32).
Myth 13: Red meat consumption increases the risk of all kinds of diseases including heart disease, type 2 diabetes and cancer
We are constantly warned about the dangers of red meat. It's true that some studies have shown negative effects, but these studies have usually lumped processed and unprocessed meat together.
The largest studies (one with over a million participants and the other with over 400,000) show that unprocessed red meat is not associated with an increased risk of heart disease or type 2 diabetes (33, 34).
Two review studies have also shown that the link to cancer is not as strong as some people would have you believe. The link is weak in men and non-existent in women (35, 36).
So don't be afraid of red meat. Just make sure you eat unprocessed meat and don't burn it, as too much burnt meat can be harmful.
Myth 14: The only people who should eat a gluten-free diet are people with coeliac disease, about 1% of the population
It is claimed that no one except coeliac disease patients benefit from a gluten-free diet. This is the most severe form of gluten intolerance, affecting about 1% of all people.
However, another condition called gluten sensitivity is more widespread and may affect around 6 to 8% of the population, although there are no good statistics on this yet. Studies have shown that a gluten-free diet can reduce symptoms of irritable bowel syndrome, as well as schizophrenia, autism and epilepsy (37, 38).
It is best for people to eat foods that are naturally gluten-free (e.g. plants and animals) - and not gluten-free products. Gluten-free junk food is still junk food.
However, keep in mind that the gluten situation is quite complicated and there are no clear answers yet. Some new studies suggest that it may be other compounds in wheat that are causing some of the digestive problems - and not the gluten itself.
Myth 15: Weight loss is all about willpower and eating less and exercising more
It's often assumed that weight loss (and weight gain) is all about willpower and "calories in vs. calories out".
However, the body is a highly complex biological system with many hormones and brain centers that regulate when, what and how we eat. It is well known that genetic predisposition, hormones and various external factors have a major influence on body weight (39).
Junk food can be downright addictive and cause people to lose all control over their food intake (40).
While it is still the responsibility of each individual to do something about their weight problem, it is neither helpful nor accurate to attribute obesity to some kind of moral failing.
Myth 16: Saturated fats and trans fats are similar. They are both "bad" fats that we need to avoid.
Mainstream health organizations often lump saturated fats and artificial trans fats together and label them both as "bad fats".
It is true that trans fats are harmful. They have been linked to insulin resistance and metabolic damage, and they dramatically increase the risk of heart disease (41). Saturated fats, on the other hand, are harmless, so it makes absolutely no sense to consider these groups together.
Interestingly, the same health organizations promote vegetable oils such as soybean oil and canola oil. However, both of these oils are packed with unhealthy fats. One study found that 0.56 to 4.2% of the fatty acids contained in these oils are toxic trans fats (42)!
Myth 17: Protein removes calcium from bones and increases the risk of osteoporosis
It is commonly believed that eating protein increases the acidity of the blood and removes calcium from the bones, which can lead to osteoporosis. However, while it is true that high protein intake can increase calcium excretion in the short term, this is not true in the long term.
The truth is that high protein intake is associated with a massive reduction in the risk of osteoporosis and fractures (43).
This is an example of how blindly following conventional dietary wisdom can have the exact opposite effect of what you intend.
Myth 18: Low-carb diets and diets are dangerous and increase the risk of heart disease
Low-carb diets have been popular for many decades. However, mainstream nutrition experts have continuously warned us that these diets will eventually clog our arteries.
Since 2002, over 20 studies have been conducted on low-carbohydrate diets. These have concluded that such diets cause greater weight loss and improve most risk factors for heart disease compared to low-fat diets (44).
Although opinions are slowly changing, many "experts" still claim that low-carbohydrate diets are dangerous while promoting the outdated dogma of low-fat diets, which science has now shown to be completely useless.
Of course, low-carb diets are not for everyone, but it is very clear that they can have great benefits for people suffering from obesity, type 2 diabetes and metabolic syndrome (45, 46).
Myth 19: Sugar is mainly harmful because it provides 'empty calories' Pretty much everyone will agree that sugar is unhealthy when consumed in excessive amounts. However, many people believe that sugar is only bad because it provides empty calories.
Well, nothing could be further from the truth. When sugar is consumed in excessive amounts, it causes serious metabolic problems (47).
Many experts now believe that sugar could be the driving force behind some of the world's biggest killers...including obesity, heart disease, diabetes and even cancer.
Even though sugar is okay in small amounts (especially for physically active and metabolically healthy people), it can be a complete disaster if consumed in excessive amounts.
Myth 20: Refined seeds and vegetable oils such as soybean oil and corn oil lower cholesterol and are super healthy
Vegetable oils such as soybean oil and corn oil are rich in omega-6 polyunsaturated fatty acids, which have been shown to lower cholesterol levels. However, it's important to remember that cholesterol is a risk factor, not a disease.
Just because something changes a risk factor doesn't mean it also affects "hard endpoints" like heart attack or death...the things that really matter. The truth is that several studies have shown that these oils increase the risk of death from cancer and heart disease (48, 49).
Even though these oils have been shown to cause disease and kill people, mainstream health organizations are still telling us to eat these oils. They still don't understand that when we replace real foods with processed foods, we get fat and sick.
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Source: https://www.healthline.com/nutrition/20-mainstream-nutrition-Mythoss-debunked#section3