Understanding food and nutrition can feel overwhelming. Headlines seemingly change overnight, one day deeming a food healthy, the next claiming it causes cancer. The revolving door of fad diets, each with its own list of “good” and “bad” foods, can be confusing. Knowing how to best feed your body can feel impossible.
On top of that, mainstream nutrition is full of food myths, beliefs about food and eating that are commonly accepted as fact. These food myths are widespread within the medical community and media and are rarely questioned.
Part of the reason food myths are so pervasive is that nutrition is a relatively new science. What was once considered fact may no longer be considered as such by the scientific community, but that information can be slow in reaching the general public.
Food myths are also pervasive because many contain a kernel of truth, so untangling the exaggeration from science can be difficult. These myths and half-truths then get turned into diet books that are sold to millions and accepted as fact. It may seem innocuous, but following these myths may be counterproductive to improving your health.
Here is the truth behind six of the most common food and nutrition myths:
Eliminating carbohydrates is a helpful way to lose weight
Diet trends over the years always seem to have one aspect in common: elimination of one or more food groups. Fats, sugar, gluten, and dairy have all had their moment, but the idea that carbohydrates should be eliminated or limited is particularly persistent.
Dieters believe this idea because carbohydrate restriction does have a rapid, short-term effect on weight. Low carb diets cause the body to shed water weight, resulting in a rapid drop in the number on the scale that leads many dieters to believe it works. However, this weight does not reflect any real change in body mass and is quickly regained. In fact, no diet has ever been shown to achieve permanent weight loss in more than a small minority of people (3 to 5 percent) for more than five years, and most (approximately 60 percent) will gain more weight than they lost.
Carbohydrates are simply one of the body’s three main sources of energy, along with fat and protein. Carbohydrates are found in varying quantities in many different foods, including grains, vegetables, fruit, dairy, and beans, as well as the added sugars, sweets, and processed foods with which carbohydrates are commonly associated. While the average American would benefit from swapping less nutritious sources of carbohydrates with more nutritious sources — like fruit, vegetables, whole grains, and beans — eliminating carbohydrates does not help.
BMI is an accurate measure of health
BMI, or Body Mass Index, compares height to weight. It is often used to determine health risks and sometimes to recommend “ideal” body weight. It was originally developed by a statistician in the 19th century as a way to measure a population’s average weight, not to measure health. The BMI scale has many problems, including the fact that it was developed from research that was only conducted on males. Also, it does not distinguish fat mass from heavier muscle mass, and because of this, many athletes and muscular individuals are marked as “overweight” or “obese.”
While research shows that extreme low and extreme high weights are associated with a significantly higher risk of morbidity and mortality, multiple studies show those who fall into the BMI’s “overweight” and “mildly obese” category have the lowest health risk. More so than weight, behaviors like eating fruits and vegetables, scheduling regular physical activity, not smoking, and having good social connections, are associated with health. Focusing on the scale may be a distraction from adopting health-promoting behaviors.
Gluten is unhealthy
Gluten, a protein naturally found in wheat, barley, and rye, has become demonized of late, thanks to the popularity of gluten-free and paleo diets. Some people have celiac disease, an autoimmune disease that causes the body to react to even a small amount of gluten, while others have a gluten intolerance, which is a less understood intolerance to gluten. Those who are diagnosed with these conditions will benefit from a gluten-free diet. While many have undiagnosed celiac disease or gluten intolerance, they comprise a small minority of the population; for everyone else, eating gluten-containing foods is perfectly safe and healthy!
In fact, needlessly going gluten-free can pose health risks. For one, most gluten-free convenience foods are more processed, with added sugars, fats, and starches to replicate the taste and texture of their gluten-containing counterparts. Gluten-free foods often contain less fiber, especially if not labeled whole grain. Because rice flour is a common wheat substitute in gluten-free foods and rice can accumulate heavy metals, a gluten-free diet may increase risk of arsenic and mercury exposure.
Many people go on a gluten-free diet and report feeling better or having more energy. For most, this is due to the fact that going gluten-free usually means eating more fresh foods and less processed foods. Sometimes, a change in food choices can be made without completely eliminating gluten. For others with irritable bowel syndrome who get relief from eliminating gluten, it may actually be due to a specific fermentable carbohydrate found in wheat, not gluten, that can cause gas and bloating in susceptible individuals. Because these fermentable carbohydrates are found in many other foods, these individuals would benefit from working with a dietitian who specializes in IBS and gut health to identify specific trigger foods.
Don’t eat after 8 pm.
“Eat after 8, and you’ll gain weight” has a nice ring to it, but it’s not true. It is based on the myth that the body cannot properly metabolize food during sleep. However, the body has intricate systems of metabolizing, storing, and using energy from food. Whatever is “unused” overnight will be there to fuel the body tomorrow. While the body requires less energy during rest, the heart still beats, the gut still digests, lungs still breath, and the brain still works — all activities that require a significant amount of energy.
Many people have a work or life schedule that necessitates eating later at night. While eating a heavy meal before bed can disrupt sleep or be problematic for those who struggle with gastric reflux, it is otherwise safe.
This myth has a kernel of truth because many people struggle with mindless eating or binge eating after dinner. Often this is fueled by inadequate intake earlier in the day, a need to cope with the stress of the day, or a combination of both. If this is the case, working with a dietitian who specializes in disordered eating may be helpful.
Supplements are needed for optimal health
Ideally, you should consume nutrients from food first. The body is designed to better absorb the nutrients that come from whole foods versus supplements. While some may benefit from supplementing a specific nutrient for a therapeutic purpose or treating a nutritional deficiency, for most, eating a wide variety of food from all the different food groups is enough to meet nutrient needs.
Some people assume that if some of a nutrient is good, more is better. Many vitamin and mineral supplements contain more than 1,000 percent daily needs of certain vitamins and minerals. For some nutrients, what the body does not use is eliminated in urine (“expensive urine,” as many dietitians joke), but other nutrients can accumulate to toxic levels.
The supplement industry is highly unregulated, and countless supplements have been removed from the market after being discovered not to contain the contents they claim to include or are being adulterated with additional ingredients. Also many supplements are sold with vastly exaggerated claims of their benefits. If considering a supplement, talk to your doctor first because even something that is “natural” is not risk-free.
Detoxes are important for helping your body eliminate toxins
Detox diets and juice cleanses have become a popular way to “reset” after a period of indulgence. The idea is that by eliminating certain foods considered to be sources of toxins or inflammation, usually sugar and processed foods, and limiting the diet to only specific healthy foods, the body can more effectively “detox,” or heal itself.
In reality, the body has complex mechanisms that eliminate toxins by breathing, sweating, and going to the bathroom. Eating a balanced diet with plenty of nutrient-dense foods can support these natural processes, and while some compounds in specific foods can aid the body’s detoxification processes, like sulforaphane in cruciferous vegetables, no specific food is detoxifying in and of itself.
Furthermore, many backlash eat, which means that after the cleanse ends they eat even more of the unhealthy foods. In the end, restriction often leads to eating more of the foods one is trying to limit.
Food and nutrition are much more complex than individual foods or nutrients. When it comes to health, the big picture of your eating patterns is what matters. Instead of getting wrapped up in following specific rules about what, when, and how to eat, focus on positive changes, like eating more fruits and vegetables, eating mindfully, and cooking at home more often.