7 Top Diet Myths Debunked

January 29, 2020
Ann Louise Gittleman, PhD, CNS

Ann Louise Gittleman, PhD, CNS

Award-winning nutritionist and New York Times bestselling author.

It’s really confusing out there on the dietary landscape, now so more than ever. And, diet myths don’t help.

Over the course of my career, I’ve seen diet myths come and go, and every new trend simply rehashed and repackaged from days gone by (witness the latest Keto diet rage which is really just phase one of the Atkins Diet). As a consumer, it can get downright frustrating as you navigate the weight loss waters, desperately trying to figure out what to believe and what really works. In fact, typical food and health surveys reveal that 8 out of 10 participants are confused on what foods to avoid or eat.

It’s high time to look beyond the latest trends, crazes and fads and get to the truth. And, I’m here to help — I’ve done the research and discerned fact from harmful fiction and it’s time to debunk 7 top diet myths once and for all.

Diet Myth #1: All Omega 6 Fats Cause Inflammation

This is one of the most pervasive and persistent diet myths in the nutrition world. Even today, very well known and respected Functional Medicine doctors are spreading the myth that all omega-6 fats are inflammatory. Their opinion is based on one large study called the Lyon Diet Heart Study, which found that decreasing dietary omega-6 fats while increasing omega-3 fats reduced heart attacks by 70 percent, was cancer protective, and lowered mortality rates.

The problem with this study is that it didn’t differentiate between the toxic omega-6 fats so prevalent in commercial use today (think corn oil, soybean oil and canola oil) and the health promoting ones (hemp seed oil, pine nut oil, sesame oil and supplements like CLA and GLA).

Americans are far too reliant on processed foods, which are loaded with the overheated, hexane-embedded, ultra-refined, toxic omega-6 oils like soybean, canola, “vegetable,” and corn oils. Once these oils enter your digestive system, your body takes them up and inserts these chemically adulterated fats into your cell membranes, causing inflammation and weakening its protective function, leaving the cell vulnerable to disease.

On the other side of the coin, the right omega-6s are membrane medicine and support the very structure of the cell membrane itself, allowing the right nutrients to get in and the toxins to get out. It protects the cell from outside viruses, bacteria and parasites.

To rebuild health at the cellular level, you ideally need healthy omega-6 fats in a ratio of 4:1 with omega-3 fats. Organic nuts and seeds, and their cold-pressed oils are the best sources of these essential fats, with hemp hearts and hemp seed oil being close to ideal with a 3:1 ratio of omega-6 to omega-3. When you avoid the toxic omega-6s so common in processed foods, and focus on health-promoting sources, your risk of heart disease and cancer goes down, not up.

For more therapeutic benefits, consider CLA (conjugated linoleic acid) to get rid of tummy fat and GLA (gamma linolenic acid) to support healthy skin and avoid bagging and sagging as you tone and lose weight.

Diet Myth #2: Eating Fat Makes You Fat

It’s shocking to me how many people still believe this diet myth, even with the popularity and success of higher fat diets that are all the rage right now. The latest research makes it clear – it’s refined sugar and toxicity that makes us fat. Think about the most common diet recommendation from the last fifty years – low fat, high carbohydrate. This is the exact opposite of what we should have been doing, so it’s no surprise that obesity, diabetes, heart disease, and many other chronic illnesses are now raging out of control.

Fears about fat started way back in the 1950s when researcher Ancel Keys, in his Seven Countries Study, cherry-picked data to support his theory that saturated fat consumption caused cardiovascular disease. The media picked it up and ran with it, and by 1961, even the American Heart Association had jumped on board and issued anti-fat guidelines. It wasn’t long before food producers created processed wonders that lowered the fat while loading up the sugars to “save us” from the horrible foods that supposedly clogged up our parents’ arteries and shortened their life spans. Sadly, these low fat, high carb diets have led millions to an early grave, and ill-informed health professionals still cling to these health-damaging beliefs.

The truth is, your body can’t make healthy cells without dietary fat. Your body needs fats for proper hormone production, cell messaging, keeping inflammation at bay, and so much more. Fats are crucial to the functioning of your heart, brain, and nervous system. Your body was built to run primarily on fats – not sugar – and fats fuel your metabolism, balance your blood sugar and insulin levels, starve cancer cells, and melt off body fat. That’s right – you need to eat fat to lose fat. But, don’t forget that it’s important to be sure you’re eating healthy fats and avoiding toxic fats as discussed in Diet Myth #1.

Diet Myth #3: You Can’t Have Too Much Protein in Your Diet

When you go on a low carb diet like Keto or Paleo, it’s easy to eat a lot of protein. But, each of us has a “sweet spot” for protein intake. If you eat too much, it’s hard on the kidneys and liver, which must work overtime to metabolize it into glucose and store it as body fat. If you eat too little protein, it can slow down your metabolism, and cause weight gain, loss of muscle mass, unstable blood sugars, insomnia, fatigue, mood swings, and impaired immune function.

The problems with protein consumption don’t end there. Many of us may be taking in enough protein, but it isn’t good quality, so our bodies can’t use it. If you are getting your protein from processed foods and toxic factory-farmed animals, they are too low quality for your body to use them and they become inflammatory and disease-promoting. The best approach is a clean, whole food-based diet with a wide variety of organic and grassfed and/or pastured protein sources.

Each of us has a unique protein “sweet spot,” determined by our age, gender, body weight, activity level, and overall health. The latest research suggests that anywhere from 20-30 g of protein per meal is ideal for most people. If you’re over 60 and find that you’re losing muscle, are recovering from surgery or an accident, you may want to aim for at least 100 g per day total. Build meals around lean protein sources, like lean grassfed beef, pastured chicken, turkey and eggs, and supplement with whey protein or pea and rice protein for an extra boost.

Diet Myth #4: All Soy Products are Bad for You

We’ve had a love-hate relationship with soy for years. Soybean oil is included in the list of toxic omega-6 fats (shared in Diet Myth #1) and promotes inflammation and disease. Some soy products are also goitrogens, decreasing thyroid function and contributing to the thyroid disease epidemic. Soy baby formulas have been implicated in women struggling with infertility later in life. And soy products can be estrogenic, which is a double-edged sword, depending on your health history and genetics. Some nutritionists add all of this up and decide that all soy products should be avoided – which simply isn’t true.

Keep in mind that for years soy was not grown as an edible crop but rather as part of a plant-rotation process to add nitrogen to the soil. And today, more than half the soybeans grown in the United States are genetically-engineered (GMO) and treated with pesticides that increase the amount of hormone-disruptive isoflavones. The bad news continues when you consider that:

  • as many as 1 in 5 people are allergic to soy
  • unfermented soy contains phytates, which bind to essential minerals, preventing absorption of those minerals
  • genistein can prevent normal brain function by inhibiting at least three metabolic pathways
  • there are protease inhibitors in unfermented soy that may prevent pancreatic enzymes from digesting protein effectively

But, on the other hand, the right soy products can reduce cholesterol – especially harmful LDL levels. Isoflavones found in soy can be a menopausal woman’s best friend, alleviating hot flashes and other problematic symptoms. Fermented soy products lower circulating estrogen levels, act as an adaptogen to help your body deal with stress, are considered probiotics, and have anti-cancer and anti-inflammatory effects.

Every health-promoting effect I’ve listed can be found in tempeh and miso. Both of these soy products are fermented. Fermentation breaks down goitrogens and difficult-to-digest compounds, releasing the nutrients and making them more digestible. Miso adds “umami” flavor to foods, and is added after cooking and before eating in tablespoon amounts. Tempeh is an excellent vegetarian protein source and can be used to make the main dish in your heartiest meals. As always, choose clean, organic sources, like South River Miso.

Diet Myth #5: Salt Drives Up Blood Pressure and Increases Heart Attack Risk

According to the DASH Study published in 1997, salt is the villain behind high blood pressure and associated heart attacks – but this information is one of those diet myths that should literally be taken with a grain of salt. Numerous studies have been done in more recent years showing salt isn’t actually to blame for your blood pressure rising. A study published by the Boston University School of Medicine in 2017 showed that over a 16-year period, participants from the Framingham Offspring Study who consumed less than 2500 mg of sodium had higher blood pressure than the participants who consumed higher amounts of sodium.

The truth is, salt is an essential nutrient in your body. It is not only used to balance fluids in the blood and maintain a healthy blood pressure, your nerves and muscles also need it to function properly. Sodium is so crucial to your body that if you go low enough, you can slip right from confusion and dementia-type symptoms into a coma and even death!

A recent study showed a diet high in sea salt actually increases metabolism. So don’t be afraid to salt your food with real sea salt, rich in a variety of minerals, not the laboratory-concocted sodium chloride table salt.

Diet Myth #6: Only People with Celiac Disease Need to Give Up Gluten

Gluten is found in wheat, barley, rye, and a few other grains, and is one of the most heavily consumed proteins in the world. The most serious gluten-related condition is Celiac Disease, an autoimmune disorder that affects about one percent of the world’s population. If you have Celiac and you ingest gluten, the damage starts in your small intestine and eventually causes widespread nutrient deficiencies, neurological problems, osteoporosis, gallbladder disease, and even cancer. But Celiac isn’t the only reason to completely eliminate gluten from your diet.

Everyone, to some extent, is sensitive to gluten. That’s because every food you eat has some sort of protective mechanism to keep it from being eaten. In gluten’s case, the first thing it does is increase intestinal permeability in everyone who eats it. If you are sensitive to gluten, not only will it increase your intestinal permeability, it will increase inflammation, which weakens your intestinal walls and further increases permeability, allowing whole proteins to pass through and wreak havoc throughout your body.

Once the whole gluten protein is circulating in your body, it can travel anywhere. When it gets to the thyroid, it’s particularly problematic. Gluten contains the protein gliadin, which is closely related in structure to your thyroid tissue. Your body mounts a defense against gliadin and attacks it, but also attacks its own thyroid tissue because it can’t tell the difference. So gluten literally turns your body against its own thyroid gland, which can lead to autoimmune thyroid disease.

Whether you are gluten sensitive, have thyroid disease, Celiac disease, or other gluten-related issues, it isn’t enough to just cut back on gluten. You must eliminate it completely, with no cheating or indulging at all. Depending on the study you read, it can take up to 18 months for gluten to completely clear your body, and even one “cheat meal” starts the clock all over and undoes all your hard work.

If you’re aiming to go gluten-free, be aware that many “gluten-free” foods on the market also contain lots of sugar, grains and starchy potatoes which are especially not ideal for those on a low-carb diet. Furthermore, too much rice can add excess arsenic to your daily regimen. For those going gluten- AND grain-free I suggest almond flour, coconut flour, tiger-nut flour, Jerusalem artichoke flour and even sweet potato flour as well as chickpea flour!

Diet Myth #7:   Your DNA Rules Your Destiny

We used to think our genes controlled our destiny when it comes to metabolism, body mass and overall health. But the science of epigenetics has turned that model on its head. Our genes are actually malleable!

Simply stated, epigenetics is the study of the changes produced by variations in gene expression, rather than from alterations of the genetic code itself. These changes affect how your cells interpret your genetic blueprint. Think of your DNA as the operating system and your epigenome as the apps–which get updated on a daily or even hourly basis.

Epigenetic changes occur when genes are flipped on and off in response to a variety of conditions. These changes are triggered by such factors as diet and lifestyle habits, environmental stimuli, and even thoughts and emotions. Basically, everything you do affects your genetic expression–eating, sleeping, exercising, laughing, crying, loving, raging. The field of epigenetics has provided new insights into everything from weight-loss resistance to heart disease to mental health.

Armed with this knowledge, you no longer have to accept your weight loss struggles as simply “fate.”  The right diet, daily lifestyle habits and even thoughts and emotions can help you finally flip the switch to reset your metabolic circuit breaker for good!

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Ann Louise Gittleman, PhD, CNS, is an award-winning New York Times bestselling author of more than thirty books including The Fat Flush Plan series and her latest book, Radical Metabolism. She’s been rewriting the rules of nutrition for more than 40 years and is internationally recognized as a pioneer in the field of diet, detox and women’s health issues. 

For a FREE daily dose of tips and strategies for maintaining healthy weight, conquering insomnia, and much more…check out my Radical Health Tips.

I’d like to meet and greet you on my Facebook groups, so won’t you check us out at the Radical Metabolism RevolutionFat Flush Nation, or my Inner Circle!


  1. Tracy

    This is such an important article to help sort through the chaotic myths out there!! Thank You!!

  2. Barbara

    I really learned a lot from your article. I’ve been fooled by these myths for years.


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