Nutrition affects everyone, and there are many approaches and beliefs about what’s best.

Even with evidence to support them, mainstream and alternative practitioners often disagree on best practices.

However, some people hold beliefs about nutrition that have no scientific support.

This article looks at some of the myths that people sometimes share in the field of alternative nutrition.

Sugar occurs naturally in many foods, especially fruits and vegetables. However, it’s also a popular additive.

There’s plenty of evidence that adding too much sugar to food is harmful. Scientists have linked it with obesity, insulin resistance, increases in belly fat and liver fat, and diseases such as type 2 diabetes and heart disease (1, 2, 3, 4, 5, 6).

However, avoiding added sugar can be difficult. One reason is that manufacturers add it to many premade foods, including savory sauces and fast foods.

In addition, some people experience cravings for foods that are high in sugar.

This has led some experts to believe that sugar and the foods that contain it have addictive properties.

There’s evidence to support this in both animals and humans. Sugar can activate the same areas in the brain as recreational drugs, and it can cause similar behavioral symptoms (7, 8).

Some go as far as to claim that sugar is eight times more addictive than cocaine.

This claim stems from a study that found that rats preferred water sweetened with sugar or saccharin over intravenous cocaine (9).

It was a striking result but didn’t prove that sugar has an eightfold addictive lure for humans, compared to cocaine.

Sugar can trigger health problems, and it may be addictive. However, it’s unlikely to be more addictive than cocaine.

SummarySugar can be unhealthy and may be addictive, but it’s unlikely to be eight times as addictive as cocaine.

Some people think that calories are all that matter for weight loss.

Others say that you can lose weight no matter how many calories you eat, as long as you choose the right foods. They consider calories irrelevant.

The truth is somewhere in between.

Eating certain foods can help support weight loss by, for example:

  • boosting metabolism, which increases the number of calories you burn
  • reducing appetite, which decreases the number of calories you consume

Many people can lose weight without counting calories.

However, it’s a fact that if you lose weight, more calories are leaving your body than entering it.

While some foods may help you lose weight more than others, calories will always affect weight loss and weight gain.

This doesn’t mean that you need to count calories to lose weight.

Changing your diet so that weight loss happens on autopilot can be just as effective, if not better.

Summary Some people believe that calories make no difference to weight loss or gain. Calorie counting isn’t always necessary, but calories still count.

Extra virgin olive oil is one of the healthiest fats available. It contains heart-healthy monounsaturated fats and powerful antioxidants (10, 11).

However, many people believe it’s unhealthy to use it for cooking.

Fats and antioxidants are sensitive to heat. When you apply heat, harmful compounds may form.

However, this mainly applies to oils that are high in polyunsaturated fatty acids, such as soybean and corn oils (12).

The polyunsaturated fat content of olive oil is only 10–11%. This is low, compared with most other plant oils (13).

Indeed, studies have shown that olive oil maintains some of its healthful properties, even at high heat.

Although there may be a loss of antioxidants, vitamin E, and flavor, olive oil retains most of its nutritional properties when heated (14, 15, 16).

Olive oil is a healthy choice of oil, whether raw or in cooking.

Summary Olive oil can be a suitable choice for cooking. Studies show that it can withstand cooking temperatures, even for long periods of time.

Heating food in a microwave oven is fast and highly convenient, but some people believe this comes at a cost.

They claim that microwaves produce harmful radiation and can damage the nutrients in food. However, there doesn’t appear to be any published evidence to support this.

Microwave ovens use radiation, but their design prevents this from escaping (17).

In fact, research suggests that microwave cooking may be better for preserving nutrients than other cooking methods, such as boiling or frying (18, 19, 20).

There’s no scientific evidence that microwave cooking is harmful.

Summary No published studies show that microwave ovens are harmful. On the contrary, some research suggests they may help preserve nutrients that other cooking methods destroy.

Nutritionists often disagree on the effect of saturated fats and dietary cholesterol.

Mainstream organizations, such as the American Heart Association (AHA), recommend limiting the intake of saturated fats to 5–6% of calories, while the 2015–2020 Dietary Guidelines for Americans recommend a maximum of 10% for the general population (21, 22)

Meanwhile, some evidence suggests that eating foods that are high in cholesterol and saturated fats may not increase your risk of heart disease (23, 24, 25, 26).

As of 2015, the U.S. Department of Agriculture's (USDA's) Dietary Guidelines no longer contain advice on limiting cholesterol intake to 300 mg a day. However, they still recommend eating as little dietary cholesterol as possible while following a healthy diet (27).

However, some people have misunderstood this and believe that blood cholesterol levels are also unimportant.

Having high levels of cholesterol in your blood can increase your cardiovascular disease and other health conditions. You shouldn’t disregard them.

Following a healthful lifestyle — including a diet that’s rich in fresh fruits and vegetables and low in processed foods, fat, and sugar — can help you maintain suitable cholesterol levels.

Summary Cholesterol and saturated fat in foods may be harmless, but cholesterol levels in your bloodstream can affect your heart disease risk.

Mycotoxins are harmful compounds that come from mold (28).

They’re present in many popular foods.

There’s a myth that most coffee contains dangerous levels of mycotoxins.

However, this is unlikely. There are strict regulations controlling mycotoxin levels in foods. If a crop exceeds the safety limit, the producer must discard it (29).

Both molds and mycotoxins are common environmental compounds. In some places, almost every person has detectable levels of mycotoxins in their blood (30).

Studies show that if you drink 4 cups (945 mL) of coffee a day, you would consume only 2% of the maximum safe mycotoxin intake. These levels are well within the safety margin (31).

There’s no need to fear coffee due to mycotoxins.

Summary Mycotoxins are harmful compounds that are fairly ubiquitous, but the levels in coffee are well within safety limits.

Some people follow an alkaline diet.

They argue:

  • Foods have either an acidic or an alkaline effect on the body.
  • Acidic foods lower the pH value of the blood, making it more acidic.
  • Cancer cells only grow in an acidic environment.

However, research doesn’t support this view. The truth is, your body regulates your blood’s pH value, regardless of your diet. It only changes significantly if you has severe poisoning or a health condition like chronic kidney disease (32, 33).

Your blood is slightly alkaline by default, and cancer can also grow in an alkaline environment (34).

People who support the diet recommend avoiding meat, dairy, and grains, which they deem acidic. “Alkaline” foods are said to be mostly plant-based foods, such as vegetables and fruit.

The alkaline diet may provide benefits, but that’s because it’s based on healthy, whole foods. Whether these foods are “alkaline” or “acidic” is unlikely to have an effect.

Summary Foods cannot change the pH value (acidity) of the blood in healthy people. There’s no convincing evidence to support the alkaline diet.

Another myth states that dairy causes osteoporosis. This is an extension of the alkaline diet myth.

Supporters claim that dairy protein makes your blood acidic and that your body takes calcium out of your bones to neutralize this acidity.

In reality, several properties in dairy products support bone health.

They’re a good source of calcium and phosphorus, the main building blocks of bones. They also contain vitamin K2, which may contribute to bone formation (35, 36, 37).

Furthermore, they're a good source of protein, which aids bone health (38, 39).

Controlled, human studies indicate that dairy products can improve bone health in all age groups by increasing bone density and lowering your risk of fractures (40, 41, 42, 43).

While dairy isn’t essential for bone health, it can be highly beneficial.

Summary Some people claim that dairy products can harm bone health, but most studies show the opposite.

Low-carb diets have numerous benefits.

Studies show they can help people lose weight and improve various health markers, especially for metabolic syndrome and type 2 diabetes (44, 45, 46, 47, 48).

If lowering carbs can help treat certain health problems, some people believe that carbs must have caused the problem in the first place.

As a result, many low carb advocates demonize all high carb foods, including those that offer a range of benefits, such as potatoes, apples, and carrots.

It’s true that refined carbs, including added sugars and refined grains, can contribute to weight gain and metabolic disease (49, 50, 51).

However, this isn't true for whole carb sources.

If you have a metabolic condition, such as obesity or type 2 diabetes, a low carb diet can help. However, that doesn't mean that carbs caused these health problems.

Many people remain in excellent health while eating plenty of unprocessed high carb foods, such as whole grains.

A low carb diet is a healthy option for some people, but it’s not necessary or suitable for everyone.

Summary Low carb diets can help some people, but this doesn’t mean that carbs are unhealthy — especially those that are whole and unprocessed.

The health food market has expanded rapidly in recent years, but not all of its products are healthy.

One example is the sweetener agave nectar.

Added sugars can cause health problems, and one reason is their high fructose content.

Your liver can only metabolize certain amounts of fructose. If there’s too much fructose, your liver starts turning it into fat (52, 53).

Experts believe this may be a key driver of many common diseases (54).

Agave nectar has a higher fructose content than both regular sugar and high fructose corn syrup. While sugar contains 50% glucose and 50% fructose, agave nectar is 85% fructose (55).

This may make agave nectar one of the least healthy sweeteners on the market.

Summary Agave nectar is high in fructose, which can be difficult for your liver to metabolize. It's better to avoid sweeteners and added sugar where possible.

Myths abound in the world of alternative nutrition. You may have heard some of these claims on social media or blog posts, or simply from friends and family.

Nonetheless, many of these assertions don't stand up to scientific scrutiny. For example, studies have disproven the notions that carbs are always harmful, that you shouldn't microwave your foods, and that agave nectar is a healthy sweetener.

While it's great to take your health into your own hands, you should always be on the lookout for dubious claims. Remember that a significant number of wellness and nutrition tips are evidence-based.