19 popular nutrition claims (some are false!)

There are so many conflicting nutrition claims out there that it is nothing short of confusing!

• The best diet is vegan/vegetarian/Mediterranean/[insert other diet here]
• We need 3,000/7,000/10,000 steps per day for good health
• We are 1x/10x more microbes than human
• Coffee is healthy/dehydrates you/causes cancer
• Protein is good/bad for your bones
• Multivitamins improve your health/do nothing/increase your risks
• etc.

Which of these are true (and is the answer really that “black-and-white”)?

Oh, and don’t worry—all of the references are linked so you can read them for yourself. The links are either directly to the studies/credible sites themselves or to articles I’ve written on the topics that list the studies/credible sites that I cited.

Are these nutrition claims true or false?

1 – Our guts are closely linked to our brains and moods

• Short answer: Yep!
• Long answer: Research on the microbiome-gut-brain-axis has exploded in recent years. The mind affects the gut (you know when you feel “butterflies” in your stomach) and vice versa—your gut and the “friendly microbes” that live in it impact your brain and moods. New research shows correlations (not proof of cause and effect) between what microbes live in your gut (e.g., ones known to produce inflammatory compounds) and mental health.

*Want to share this study about how the gut microbiota influences mental health (and vice versa), along with a few practical tips on how to nurture a healthy gut microbiome to help optimize gut health, brain health, and mental health? Check out the customizable done-for-you article here.

2 – Plant-based diets are better for your health and the Earth

• Short answer: Yep! (But you don’t have to go 100% vegan, just focus on having about 80-90% of what you eat from plants—not vegetarian junk food.)
• Long answer: Eating mostly plants is highly recommended based on the majority of nutrition studies worldwide. This is also exemplified in Canada’s industry-free science-based food guide. A 2020 systematic review of 18 studies found that diets that are higher in plants and lower in animals release fewer greenhouse gases and use less land and nitrogen (but they may use more water than animals). These “sustainable” plant-rich diets also reduce the risks of diabetes, cancer, and heart disease. And you don’t have to go fully vegan or vegetarian to realize these benefits.
• In fact, there is growing evidence that eating a diet similar to the “MIND diet” that focuses on whole grains, vegetables, fruit, nuts, and beans, with small amounts of poultry and seafood) is linked to reduced risks of Alzheimer’s symptoms. Also, a 2021 review of 153 studies showed that eating a nutrient-dense diet with a lot of plants can reduce your risk of premature death from any cause.
• Oh, and one more thing. The more plants you eat the more fibre you get, so this feeds your friendly gut microbes which are linked with better physical and mental health (see #1 above).

*Want to share the study that found “a beneficial association between the MIND diet with global cognitive function and dementia risk” with your audience, along with the 10 “brain healthy” and 5 “not so brain healthy” food groups, and tips with placeholders to link to your recipes, etc. to help your audience start implementing more brain-healthy dietary choices?

Check out the customizable done-for-you article here.

3 – Can you get enough of all essential nutrients from plants alone?

• Short answer: Yep! (But there are a few strategies you need to use to make sure this happens.)
• Long answer: There are 7 principles for healthy vegetarian and vegan dietary patterns including:

• • Choose a variety (of unprocessed and minimally processed plant foods)
  • Focus on produce (by including a colourful variety of vegetables and fruits)
  • Consume protein regularly (ensuring protein-rich plant foods at each meal)
  • Focus on fibre (e.g., whole grains)
  • Choose unsaturated fats (e.g., nuts, seeds, avocados, and plant-based oils)
  • Ensure adequate intake of nutrients that might be limited (e.g., vitamin B12, D, calcium, iron, iodine, and choline)
  • Balance energy intake (sufficient calories without excess)

*Want to share these 7 principles of plant-based nutrition with your audience, along with examples and tips on how to easily meet this goal? Check out the customizable done-for-you article here.

4 – Do happier people lead healthier lifestyles or do healthier lifestyles increase happiness?

• Short answer: Healthier lifestyles—including better nutrition—can lead to more happiness. (The lifestyle comes first!)
• Long answer: The first study of its kind tried to determine what comes first: healthier lifestyles or happiness? Also, a clinical study found that 12 weeks of eating a Mediterranean-style diet reduced symptoms in one-third of people who already had depression. This research shows pretty promising evidence that starting a healthier lifestyle often leads to more happiness and mental health.

5 – Are high-protein diets *good* for your bones (or not)?

• Short answer: Protein is good for your bones! Protein is an essential component of your bone structure and helps to strengthen them. So, where did the myth that protein leaches calcium from your bones come from?
• Long answer: Decades ago it was found that after eating a high-protein meal there’s more calcium excreted in the urine. The question was: Where did this calcium come from? One hypothesis was that it came from the bones. But we also knew that people who ate more protein tended to have stronger bones, so that hypothesis needed to be tested. Mre studies were done to find out where this extra urinary calcium comes from, and in 2004 we learned that it comes from the meal itself—not your bones! This is because when we eat a high protein meal, our body absorbs more calcium from that meal. So, if it’s more than we need at the time, our kidneys excrete the excess in the urine (as they do for water-soluble vitamins and minerals).

6 – How many steps are needed each day for good health? 7,000? 10,000?

• Short answer: As little as 7,000 steps per day help reduce premature death.
• Long answer: Don’t get me wrong: physical activity is amazing for your health! Activity helps with physical health and mental health. That’s not debated. There isn’t a universally agreed-to “magic” number of steps to take per day, but at least some studies show that as few as 7,000 steps per day is just as good at reducing premature death as 10,000 steps per day.

7 – It really is hard to “bounce back” into fitness after having a baby

• Short answer: True! If this is you, you’re 100% right that it’s hard.
• Long answer: It can take some of the fittest people—active-duty soldiers—months or even years to regain the core strength and cardiovascular endurance they had before pregnancy. In other words, it’s definitely doable, it just takes some time.

8 – Are we 50% microbes or 90% microbes?

• Short answer: We are 1/2 microbes (50%)!
• Long answer: Back in 1977, the first estimate of how many microbes lived in our guts was published, but there was some skepticism. In 2016 a much more accurate measurement was made and the best information we have now is that we’re about 50% microbe (not 90%, unlike some of the attention-getting headlines). Basically, this means that for every human cell we have (e.g., skin cells, brain cells, muscle cells), we have about the same number of tiny microbes living in us. In other words, for every two cells in our body, one is our own cell and one is a microbial cell.

9 – Probiotic supplements reduce gut issues from antibiotics

• Short answer: Very few have proof of this. Most supplement companies have not spent the time or money to test this nutrition claim on their specific products, so this has only been proven with one probiotic (that I know of).
• Long answer: If gut issues are a concern when taking antibiotics, stick with those probiotic supplements who have the clinical evidence that their product works. One example is Bio-K+ (and no, I’m not an affiliate – they just really stand head and shoulders above all other probiotic companies as far as evidence is concerned). Here’s their approved label claim (see the “Recommended use or purpose”).

10 – How many glasses of water each day do we need to drink to stay healthy? 8? More?

• Short answer: As many as you need to satisfy your thirst. In other words, there is no magic number that applies to everyone equally.
• Long answer about how much water to drink: If you’re healthy, your body can self-regulate its hydration and you only need to drink to thirst. Note that this doesn’t apply to children, older adults, athletes, or people prone to kidney stones or urinary tract infections—if this is you, you probably need to drink more than just to thirst.
• What if you drink coffee? Coffee can count toward your fluid intake for most people. As long as you stick to moderate doses (up to 300mg of caffeine) and your body is used to regular caffeine intake, the caffeine doesn’t impact hydration (but, excessive amounts can start becoming dehydrating).

11 – The best drink when you’re thirsty is . . .

• Short answer: Other than specifically formulated oral rehydration solutions (ORS) which are the best at hydrating (more on them below), the most hydrating beverages according to the Beverage Hydration Index (BHI) are skim milk (yep, skim milk), full-fat milk, and orange juice. These are all more hydrating than plain water.
• What’s an ORS? These are electrolyte products specially formulated to help replenish fluids lost due to severe dehydration (intense diarrhea or vomiting). These are available under brand names like Pedialyte and HydraRescue/HydraRestore.
• When should you choose ORS/electrolytes? Oral rehydration drinks can be very helpful to replenish electrolytes/minerals lost due to excessive dehydration, but most people don’t need them most of the time. If you’ve been experiencing severe gastrointestinal issues (intense vomiting or diarrhea) or if you’ve been sweating a ton, then you may need to replenish lost electrolytes. Here’s a resource on how to make your own ORS, but know that ORSs won’t stop the fluid loss, they will help replenish lost fluids and electrolytes.
• What about coffee and tea? Coffee and tea are slightly less hydrating than plain water, but still are considered hydrating (not dehydrating) (see #10 above).

12 – Is coffee healthy . . . or not?

• Short answer: Overall, coffee is healthy!
• Long answer: About 3-4 cups of coffee per day is healthy in most people. People who drink more coffee tend to have lower risks for or improvements in: heart disease, diabetes, depression, obesity, neurodegenerative diseases, and liver diseases including liver cancer.
• Coffee isn’t without its risks, though. Look out for high blood pressure, palpitations/arrhythmia, insomnia, and headaches. Plus, for women, coffee may increase your risks of fracture and, during pregnancy, low birth weight and preterm labour.
• When it comes to cancer risks, impossibly huge amounts of one substance found in many roasted foods/drinks (including coffee) can cause cancer in rodents.

13 – Alcohol and beer increase your risk of cancer and are poor sources of nutrients

• Short answer: True! Alcohol-containing beverages are not health foods.
• Long answer: There is pretty convincing evidence that people who drink more alcohol tend to get more cancers of the: mouth, pharynx, larynx, esophagus, stomach, liver, colorectal, and breast. But, they do have lower risks of kidney cancer.
• What about beer? Beer has tiny amounts of some B-vitamins, but unlike eating the whole grains (beer ingredient) themselves, beer is a pretty bad source of any vitamins. Plus, it contains alcohol which is very strongly linked to some cancers.

14 – Melatonin supplements are safe and effective

• Short answer: Sort of (but they’re not for everyone).
• Long answer: Melatonin supplements have a lot of contraindications (see Risk Information) that you should know about before taking them. Also note the recommended dosages and whether the melatonin is to be taken orally (swallowed) or sublingually (under the tongue).

15 – Do multivitamins have health benefits beyond simply producing “expensive pee”?

• Short answer: Multivitamins have some health benefits for some people, but multivitamins don’t guarantee great nutrition or long-term health.
• Long answer: Multivitamins are safe and can help fill nutrition gaps. The “expensive pee” claims are due to the fact that when your body has enough of many water soluble vitamins and minerals, it pees out the excess (note this doesn’t apply to fat-soluble vitamins that can be toxic at high doses such as A, D, E and K or minerals like iron). A just published (Jan 2026) review of 19 studies that includes a total of 5,535,426 participants confirmed correlations between some people who take multivitamins and lower risks of heart disease and some cancers. Clinical trials show benefits on cognition, infection, and blood pressure (but no benefits on mortality) for those people who take multivitamins. When it comes to pregnancy, multivitamin use reduces the risk of pediatric cancer.
• What about maternal multivitamins/folic acid supplementation? Folic acid (vitamin B9) is known to support DNA methylation and neurodevelopment. It’s been long known that folic acid supplementing during pregnancy reduces the risk of neural tube defects (spina bifida) in newborns. A recent review of over 3 million mother-offspring pairs found that taking multivitamins during pregnancy was also associated with a 30% reduced risk of autism spectrum disorder.

16 – How healthy is turmeric, really? (And what’s the difference between turmeric and curcumin?)

• Short answer: Most of the health benefits of turmeric (the food) are exaggerated because they’re actually benefits of higher-dose curcumin supplements.
• Long answer: This is a classic case of foods vs. supplements. Turmeric is delicious, but only about 5-7 percent of it is the “active ingredient” curcumin. This means you need a whole helluva lot of turmeric to come close to what’s in a curcumin supplement. A 2025 review of 25 studies found that “curcumin has potentially positive effects on lipid profiles, blood pressure, inflammatory markers and oxidative stress, musculoskeletal diseases, emotional and cognitive function, ulcerative colitis, liver and kidney function, primary dysmenorrhea or premenstrual syndrome, rheumatoid arthritis, COVID-19, painful statues, and HR-QOL.”

17 – Are there documented nutrient deficiencies in Canada or does everyone get enough nutrition all of the time?

• Short answer: Maybe not full-fledged “deficiencies” per se, but yes, many people have inadequate intakes and insufficient levels of several nutrients.
• Long answer: A 2021 study found that many Canadians tend to be low in essential nutrients, such as vitamin A (47% of Cdns are low), vitamin D (94% are low), vitamin C (29% of nonsmokers and 59% of smokers are low), magnesium (45% are low), and calcium (44% are low). Many Canadians are also not getting enough fibre (75% are low) and potassium (60% are low). One more nutrient intake was concerning: sodium (48% of females and 75% of males get too much).

18 – Canada and the US have very different dairy farming practices and standards—Canada has no huge CAFO (concentrated animal feeding operation) dairy farms and doesn’t allow growth hormones

• Short answer: Correct! Canada does not have CAFOs like the US does, nor do we allow growth hormones in our dairy.
• Long answer: Here is some info on dairy farms in Ontario, from a dairy farmer I met and references that I found that verified what he said.

19 – Should I get multiple x-rays for potential broken bones?

• Short answer: Yes, if the benefits outweigh the risks.
• Long answer: Exposure to lots of x-rays at a young age can increase the risk of some cancers, but it depends on a lot of factors. Plus, there are reasonable steps you can take to reduce overexposure, including insisting on ALARA (As Low As Reasonably Achievable) and tracking your exposures.

Why are there so many contradictory nutrition claims?

For one thing, hype sells. Having clickbaity headlines about novel studies that stoke fear, disgust, and surprise spread very, very easily online. The same thing goes when trying to sell courses, books, and documentaries. It’s a simple psychology trick that gets all of us at one time or another because we’ve evolved to survive and warn others about threats to our survival. It’s an innate gut reaction. Our emotions make us persuadable.

It’s also easy (and dare I say, lazy) to read a study or two (or a book/blog post/documentary or two) and present it to the world as though it’s the truth that explains everything. We know that the human body is infinitely complex, so that’s why we often hold off until there are many, many studies looking at the same thing in different ways before we can be confident how it’s going to help (or hurt) our physiology and biochemistry.

There are elements of truth almost everywhere. There are studies that support almost every position. The key thing is that without looking at the “big picture” (i.e., many studies done over time) on one topic and understanding the strength of each type of study, it’s so frustratingly confusing.

For me, I’m not “married” to any particular diet or lifestyle. I understand that our knowledge keeps getting deeper and broader as more and more research is done to understand our health and nutrition claims.

I’ll never say that I’m 100 percent objective, even though that’s what I strive for (everyone is human!). My university education taught me how to be objective and understand study design and results. And THIS IS EXACTLY WHY I am very careful to share how strong a study is when I talk about it or to cite several high-quality resources in every single pre-written done-for-you health article that you can purchase for your blog or program.

We can all update our knowledge with better, more recent or applicable studies (they’re published daily!) and reliable resources. I’ve changed my position before, based on new evidence, and that’s a great thing!

Conclusion

There are so many popular nutrition claims that are correct and so, so many that are false. As more and more high-quality studies are published, they continue to help us get closer to really understanding the complexity of the human body.

Signing off and toasting: To finding out which nutrition claims are true!

Over to you

Are you curious if other popular nutrition claims are BS? What kinds of claims motivate you to look them up yourself? How do you go about finding the credibility of these nutrition claims?

I’d love to know (in the comments below)!

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Originally published Jan 2020; updated with even more awesomeness Feb 2022 and Jan 2026.