13 Nutrition Mistakes That Can Harm Health


A Surprised Looking Woman.Nutrition can be very confusing.

For instance, pick up a newspaper in the morning, and you may read about how eggs are good for you.

And then just as you’re getting started on your omelet for dinner, you see a TV segment warning viewers to avoid egg yolks and dietary cholesterol.

It’s no wonder people don’t know what they’re supposed to be eating; the media can’t get their story straight.

This article looks at dietary myths and misconceptions, and some of the most common nutrition mistakes that harm health.

Mistake 1: Not Eating Enough Dietary Fat

Not getting enough fat in your diet is one of the most typical nutrition mistakes.

There are two main reasons why people don’t eat enough dietary fat.

  • One reason is the widespread fear that eating fat makes you become fat. Of course, this isn’t true at all, and studies show that low carb diets result in comparable or better weight loss than low-fat diets (1, 2, 3, 4).
  • Secondly, there’s a prevalent view that we should limit fat, especially saturated, to protect our heart.

But again, there’s not much truth in this, and several large-scale studies show no association between saturated fats and cardiovascular disease (CVD) (5, 6, 7).

Additionally, here are the results of a major new study investigating nutrition and CVD:

The take-home points:

  • There are steep rises in cardiovascular risk with carbohydrate levels at over 40% of total energy.
  • Higher fat consumption is preventive.
  • Saturated fat intake appears to be neutral, and possibly even beneficial.
Key Point: There’s no need to fear dietary fat – much of the latest research shows it’s either neutral or beneficial for health.

Mistake 2: Getting Nutrients From Supplements Instead of Real Food

Gelatin Capsule Dietary Supplements Spilling Out of Their Tub.First, supplements can be useful for people dealing with certain medical conditions. However, they should never replace real food.

One of the most common dietary mistakes people make is to believe a synthetically produced vitamin is the same as a nutrient in a whole food.

There is sufficient evidence to suggest that our body doesn’t treat some synthetic and natural vitamins in the same way.

One good example of this is vitamin B9; natural and synthetic sources differ in both absorption rate and bioavailability.

Furthermore, uptake of the synthetic form (folic acid) cannot be regulated by the body in the same way as the natural version found in food can.

Therefore, there’s a risk of consuming excess doses of folic acid (89).

Another key point is that there’s no such thing as a magic pill. Despite this, many people believe multivitamins can make up for an unhealthy diet; it’s a frequent nutrition mistake, and it just doesn’t work.

Key Point: Supplements have their place, but they shouldn’t replace real food.

Mistake 3: Eating Healthy Foods in Excessive Amounts

A Picture of a Piece of Broccoli.Just because something is healthy doesn’t mean we should eat huge amounts of it.

If we look at plant foods, then many contain anti-nutrients. These compounds help protect the plant by discouraging pests and insects from eating it (10).

Additionally, anti-nutrients can cause a variety of harm to our body. But the key point is that the dose makes the poison.

A side of spinach or kale with your meal? No problem at all. On the other hand, the trend for pulverizing a few pounds of raw green vegetables every day might not be the best option.

Specifically, many raw vegetables contain significant amounts of goitrogens, which are substances that can impair thyroid function (11, 12).

Key Point: There shouldn’t be free license to eat ‘healthy’ foods in unlimited amounts, and it’s better to eat most food in sensible quantities.

Mistake 4. Not Prioritizing Real, Whole Foods

Meat, Onions and Tomatoes On a White Background.There’s a train of thought in bodybuilding and weight loss circles known as IIFYM.

This acronym stands for ‘If It Fits Your Macros,’ and the general idea is that the most important part of a diet is the macronutrient ratio and calories you consume.

For carefully controlled weight loss or muscle gain, this is likely true if people stick to it (in the short-term at least). However, it is not a healthy way to think about nutrition.

Some people following IIFYM plans do emphasize high-quality, nutritious foods, and they just like to be precise with counting calories. That’s no problem.

But others use this idea of IIFYM to eat anything they want, as long as it ‘fits their macros.’ Again, for weight purposes, this may well work (in the short-term), but over the long-term, it’s putting people’s health at risk.

Foods such as sugar, refined carbohydrates, and industrial vegetable oils have links to a wide range of chronic diseases, and they don’t belong in a healthy diet — whether they fit someone’s macros or not (13, 14, 15).

Key Point: Over-emphasis on calories and macronutrients is an everyday nutrition mistake that many people make. Food quality is important.

Mistake 5: Fearing and Avoiding Red Meat

Steak With a Sprig of Rosemary On a White Background.Red meat is “high in artery-clogging saturated fat.”

Apparently, it also “causes cancer.”

At least that’s what you can regularly hear companies (who make products full of low-fat junk) spouting in their commercials.

It’s also a message that frequently comes from dietitians and dietetic associations (often sponsored by said junk food companies – not that I’m implying anything).

And it’s a message that is wrong; fearing red meat is a recurrent nutrition blunder based on poor science.

As we discussed earlier, there’s no proof that saturated fat is not bad for us.

But What About Red Meat and Cancer?

Regarding cancer and red meat, epidemiological studies (based on food frequency questionnaires) do show a link. However, you have to question what sources of red meat people are commonly eating.

However, you have to question what sources of red meat people are commonly eating.

A slow-cooked joint of roast beef alongside a few veggies? Or a McDonald’s burger served alongside some cola and vegetable oil-nuked fries?

Judging by the fact that ultra-processed foods make up 60% of the calories people are eating, I’m betting on the latter. And in that case, is it the meat that’s causing the problem, or is it the ‘ultra-processing’ part of the equation?

And in that case, is it the meat that’s causing the problem, or is it the ‘ultra-processing’ part of the equation?

People call randomized-controlled trials (RCTs) the ‘gold standard’ of science. So, how many of these RCTS show red meat causes chronic disease? Not one.

Key Point: There’s very little evidence to suggest that unprocessed red meat is harmful – and avoiding it means restricting one of the most nutrient-dense foods.

Mistake 6: Believing Whole Grains Have Magical Health Properties

A big oversight people make is to believe that whole grains are necessary for fiber. This belief is largely an industry-driven message that isn’t true at all.

For example, let’s look at the fiber content of some typical foods:

Fiber Content of Vegetables Compared To the Fiber Content of Grains.

As you can see, 160 calories of avocado get you 7 grams of dietary fiber. In contrast, you need 247 calories of whole wheat bread to provide the same amount (16, 17).

And 111 calories of brown rice only contains a meager 1.8 grams of fiber, but broccoli provides 2.6 grams from only 34 calories worth (18, 19).

Truth be told, grains are a poor source of dietary fiber when we compare them to fruits and veggies.

Also, when it comes to fiber, more isn’t always better. Fiber is a bit of a mixed bag; there are studies showing benefit, but also others that show potential harm in excess.

As most people have likely heard the favorable sides already, here’s an article explaining the potential pitfalls of fiber on Mark’s Daily Apple.

Essential “food groups” don’t exist – essential nutrients do.

Key Point: Whole grains are far from a magical food, and fruits and vegetables provide a better source of fiber.

Mistake 7: Eating Meals Every Few Hours 

A Dietitian Holding a Meal Plan In Her Hands.We often hear the message that eating small meals throughout the day is important for our metabolism.

The truth is that it’s not necessary to eat so much food–and continuous feeding is not a natural state for our body.

Throughout human evolution, we ate what we could — when we could. We certainly didn’t plan for six small meals per day. Of course, just because we did something in the past doesn’t make it right for us now.

That said, research shows that periods of caloric restriction and fasting can vastly improve health markers. Specifically, there are improvements in insulin sensitivity, blood lipids, and metabolic function (20, 21).

Personally, I like to eat two meals per day; a big breakfast, and a medium-sized dinner in the early evening. But this is not for everyone, and all people have a different situation and preference.

The key message is that your body is not a machine that requires food at regular intervals. Eat when you want, but science suggests that a lesser frequency could be beneficial for metabolic health.

Key Point: One of the most common nutrition mistakes is to believe that we have to eat at regular intervals.

Mistake 8: Using Sugar and Other High Carb Foods For Energy

An Illustration of a Woman Running Away From Junk Food.The idea that we should use sugary food, soda, and candy for energy is rife.

The truth is that snacking throughout the day is normal – but only because it’s normalized by our society. And it really shouldn’t be.

Sugar and processed carbohydrates are not just empty calories; they are metabolically harmful:

  • Refined carbohydrates cause rapid spikes and drops in blood sugar levels, and can lead to intense food cravings and encourage binge eating (22, 23).
  • Studies show that these foods increase the risk of type 2 diabetes and cardiovascular disease independently of weight gain and other risk factors (24, 25).

A regular lack of energy is not a cue to eat sugar; it’s a sign to think about lifestyle improvements.

In this situation, it’s more important to ensure you’re eating a diet full of nutritious foods and getting sufficient sleep.

Key Point: Using lack of energy as an excuse to eat sugary snacks is a typical nutrition blunder. Instead, focus on improving your lifestyle.

Mistake 9: Strictly Restricting Sodium

A Salt Shaker Full of Salt.Is salt bad for us, and should we restrict it to improve our health?

If I ask that question to people, more than 50% agree that salt is indeed harmful.

But this simply isn’t true. 

In fact, sodium is an essential nutrient for every cell in our body and restricting salt too much may cause significant health problems.

Despite this fact, many people make the dietary miscalculation of strictly limiting salt intake.

Although it’s true that excessive amounts of sodium can cause harm, low sodium intake may also be a risk factor for heart disease (26, 27, 28).

Overall, there’s a delicate balance with salt and aiming for somewhere between 3 and 5 grams per day seems about right.

Key Point: Restricting salt too much is one of the most common nutrition mistakes. Salt is not bad for you – but insufficient or excessive amounts are.

Mistake 10: Avoiding Egg Yolks and Dietary Cholesterol

Two Hands Breaking An Egg On a White Background.Due to sub-optimal dietary guidelines, the belief that dietary cholesterol is harmful has persisted for years.

As a result, many people make the mistake of avoiding cholesterol-rich foods. And unfortunately, most of these high cholesterol foods are among the most nutrient-dense of all.

For example, here are just a few:

  • Beef liver
  • Cheese
  • Eggs
  • Salmon
  • Shellfish

Sadly, many people still make an error by believing these foods are damaging to health. On the contrary, avoiding them is much more harmful as people are missing out on a range of beneficial nutrients – especially choline (29).

Over recent years more and more research has come to light showing that dietary cholesterol intake has little effect on plasma cholesterol (30, 31).

But if you need further convincing, even the official US dietary guidelines finally changed their stance in 2015. After years of demonizing cholesterol, they simply stated that “dietary cholesterol is no longer a nutrient of concern.”

Key Point: Avoiding egg yolks is still a dietary mistake that’s very common. But if you throw away the yolks, you’re missing out on the best part.

Mistake 11: Drinking Fruit Juice

A Young Woman Drinking a Glass of Orange Juice.Most people agree that fruit is healthy and–providing you don’t binge on it–I agree.

This is particularly the case for fruits high in polyphenols such as blueberries, and avocados and olives are great too for their monounsaturated fat and mineral content.

However, fruit juice is a little bit different. And one of the most common nutrition mistakes is thinking that a glass of juice is the same as a piece of fruit.

Let’s take orange juice for example. While it does contain some nutrients such as potassium and vitamin C, processing removes all the fiber present in the whole fruit form.

Additionally, the fructose content of oranges is present in unrealistic amounts. Eating one piece of fruit provides a relatively small amount of fructose, but a big glass of juice may contain equivalent to 3 or 4 pieces – in one quick drink.

And as the naturally occurring fiber isn’t present, there is nothing to blunt the release of this fructose.

Although it’s only an association study, research involving 71,346 participants shows fruit consumption lowers diabetes risk. However, fruit juice appears to increase this risk (32).

Key Point: Preferably stick to whole fruit rather than fruit juice. It’s a much healthier choice.

Mistake 12: Thinking Calories In vs. Out Is All That Matters

A Hand Scribbling "How Many Calories?" With a Board Marker.You can’t outrun a bad diet.

Maybe you can do in terms of your weight – but you can’t regarding your metabolic health.

And contrary to what many people believe, being slim doesn’t mean that someone is healthy on the inside.

Being ‘skinny fat’ is a common phenomenon. This situation refers to someone who is slim and healthy in appearance but broken inside.

These metabolically obese individuals are very common and have a much higher chance of developing diseases like type 2 diabetes and cardiovascular disease (33).

So, “burning” the calories you consume may help you keep in shape, but it doesn’t mean you will be healthy.

Key Point: Exercise should be an addition to a healthy eating plan and not something to repair the damage of a bad diet.

Mistake 13: Thinking Calories Don’t Matter

A Basket Containing Lots of Nuts.

While some people believe counting calories is the single most important thing for health, others believe calories don’t matter.

For me, I think the truth lies somewhere in between.

Here’s an example: nuts and avocados are two of the healthiest foods you can eat. They’re full of monounsaturated fat and contain tons of beneficial nutrients. That said, if you eat them in massive amounts, then you will gain weight.

This is one of the common nutrition mistakes people make on a low-carb diet. Some people put huge sticks of butter in their coffee in addition to excessive amounts of fat at every meal, and then wonder why they aren’t losing weight.

In short; calories do matter, but the quality of those calories is the most important thing for optimal health.

Key Point: Counting calories isn’t important for the average person, but total food consumption still matters.

Final Thoughts

Understanding nutrition and planning a perfect diet can be very stressful.

However, being aware of some of these common nutrition mistakes can help guide you in the right direction.

And if you only remember one thing; one of the most important things you can do for your overall health is to focus on nutrient-dense real foods.

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