Debunking Some Food and Diet Myths

See also: Positive Body Image

Over the last few years, it seems that almost everything we thought we knew about food and diet has been proved wrong. Work from groups and organizations like ZOE have given us new insights into the role of our gut microbiome, why some people never seem to gain weight and others simply can’t lose it, and the link between diet and aging. However, many myths about food and diet have persisted despite new evidence.

This page explores some of the most common—and persistent—food- and drink-based myths. The idea is to show you that these myths are just that: myths. It aims to help you to understand the evidence, and be better able to make up your own mind about your food choices, knowing the science behind them.

Myth 1. Exercise helps you to lose weight

One of the longest-standing myths in the diet world is that if you want to lose weight, you need to exercise more.

Unfortunately, it’s completely untrue.

That’s not to say that taking exercise is bad: quite the opposite. Exercise has huge benefits for both mental and physical health. It will help you to feel better, cope with stress, and reduce your risk of developing various chronic conditions such as heart disease or stroke. However, it doesn’t help you to lose weight.

This is because the energy that you use to exercise is actually a very small proportion of your overall energy use. You actually use far more energy just staying alive than exercising. The second problem is that when you exercise, you are likely to develop muscle, and muscle weighs more than fat. Your body weight may therefore increase slightly, even if you are actually healthier.

You therefore do need to exercise—but not as a strategy for weight loss.

Our pages on Dieting for Weight Loss and The Importance of Exercise provide more information.

Myth 2. Counting calories is the best way to lose weight

For some reason, dieting for weight loss is one of the areas that attracts many of the most pernicious food-based myths.

This one is also persistent, based on the idea that to lose weight, you need to make sure that you take in less energy (fewer calories) than you use each day.

There is an element of truth in this, but the theory also has many flaws, including:

  • The number of calories in any given food is only part of the story. The structure of food has a huge effect on whether we can access the calories that it contains. For example, you will obtain far more of the energy from ground nuts than from whole nuts. However, they have the same nominal calorie count.

  • We digest foods differently based on how we eat them. Food is not just a list of ingredients or nutrients. How those nutrients are combined changes our ability to absorb the nutrients, and also how we digest the food. There is growing evidence that, eating, say, a cheese sandwich does not have the same effect on our digestive system as eating a piece of bread and some cheese.

  • We all deal with different foods differently. Thanks to our unique gut microbiomes, we all digest foods slightly differently from each other. Even identical twins do not have exactly the same reactions to foods.

The bottom line is that a calorie cannot really be considered a standard ‘thing’—and that’s before we get into whether calorie counts are accurate.

Our pages Dieting for Weight Loss and Calorie Counting and Food Labelling provide more information on this thorny issue. You may also be interested to read our page on Understanding and Improving Your Gut Microbiome for more about the influence of our gut microbes on what we can eat.

Myth 3. You should take a multi-vitamin supplement just in case you are deficient in something

Billions of us are now popping vitamin pills and other supplements every day—but why?

For most people, a balanced diet should provide more than enough for all our nutritional needs.

There seems to be a general feeling that we might be short, and therefore should take a supplement. There also seems to be a feeling that ‘it won’t hurt’ to have more. After all, vitamins are good for you, so more must surely be better.

Unfortunately, no. More is not better in this case.

The real problem is that taking a supplement is basically like dosing yourself with a chemical—and that’s not the same as eating foods containing that chemical.

There is absolutely NO evidence that taking supplements does any good. There is also a very real danger of overdosing on some of the fat-soluble vitamins in particular thanks to the number of foods that are already fortified.

Our page on Dietary Supplements explains more.

Myth 4. There are standard ‘food rules’ that work for everyone

We are used to seeing dietary guidelines that tell us to eat less fat or sugar, or no more than a certain amount of salt in a day or week.

These guidelines suggest that there is a set of ‘food rules’ that work for everyone.

Unfortunately, this too is just not true.

We are all individuals, and this is perhaps more true in how we digest food than in almost anything else. This process is hugely dependent on the bacteria and other microorganisms that live in our gut: our gut microbiome.

Your gut microbiome is unique to you. Even identical twins have very different gut microbiomes—and therefore different reactions to different food substances. Your reaction to food, and how you digest different types of food, is therefore highly personal.

There is more about this in our page on Understanding and Improving Your Gut Microbiome.

Myth 5. There’s no such thing as food intolerances and allergies

“When I was a child, nobody was allergic to peanuts! It’s all made up for attention!”

How is it that so many people (around one in five) now have food allergies and intolerances?

Are we just more aware of the issues? Or is it, as some would have you believe, just attention-seeking?

All the evidence suggests that allergies and intolerances are real. It also seems that the number of people with genuine food allergies and intolerances really is increasing—and doctors don’t really know why.

You can find out more about this in our page on Food Intolerances and Allergies.

Myth 6. Fats are bad (and/or low fat foods are better for you)

Over many years, we have been receiving messages that fats were bad for us. We were encouraged to reduce the fat that we ate as a way to improve our heart health.

Many people therefore shifted to ‘low fat’ alternatives.

The problem with this is twofold:

  • There is absolutely no evidence that dietary fat is bad for you. In fact, some studies have found that people who ate more fat lived longer than people who ate less.

  • Low fat alternatives are often more highly processed than the foods they replace. If we can be confident about one thing, it is that we are better off eating foods that have undergone less processing and are closer to their natural state, rather than choosing highly processed alternatives.

Highly processed fats are certainly bad for your health. However, the more natural alternatives, especially extra virgin olive oil, contain substances that are extremely good for our health. If anything, we should be trying to eat more of those.

It’s really a question of the processing, not the fat.

You can find out more about fats in our page What is Fat? You may also be interested to read our page on Ultra-Processed Food.

Myth 7. Organic food is just a more expensive option with no benefits

Organic food is expensive—or at least more expensive than the alternatives. Why would you pay more for what is effectively the same thing?

The real question here is whether you are paying more for the same thing, or whether there are some genuine health advantages to buying and eating organic produce.

The key argument is whether the pesticides used in non-organic production are safe. Standards for non-organic farming vary around the world, and some countries allow far more aggressive use of pesticides and herbicides. It is hard to know what residual levels may be left.

There is also a question about whether these chemicals have a harmful effect. The evidence to date suggests that they may be damaging your gut microbiome. Over time, this may have important effects on how you digest various foods, and may even lead to food intolerances.

It is therefore likely that there are some health benefits from eating organic foods—and also that there are some foods to prioritise if your budget is limited.

There is more about why you might want to switch to some organic options if your budget allows—and which options to prioritise—in our page on Organic Food.

Myth 8. A vegan diet is always the healthiest option

Many people are now switching to vegan and plant-based diets, citing three main reasons:

  • Veganism avoids exploiting any animals, or using any cruel or inhumane farming practices;

  • A plant-based diet is more sustainable and better for the planet than one containing meat or fish; and

  • A plant-based diet is better for your health.

The first two claims definitely stack up. However, the third does not, for one simple reason: it depends what plant-based foods you choose to eat.

A plant-based diet can be more healthy, if you eat a wide range of fresh fruit and vegetables, and avoid too much ultra-processed food. However, ‘fake meat’ and vegan cheese are both ultra-processed foods—and those are not good for your health.

There is more about this in our page on Veganism and Plant-Based Diets. You may also be interested in our page on Ultra-Processed Foods.

Myth 9. Drinking coffee is bad for you

We all know the stories that coffee is bad for you: it stops you sleeping, it gives you the ‘jitters’, it raises your blood pressure...

Coffee certainly gets a bad press—but this bad press is almost certainly unjustified.

Yes, coffee does contain caffeine, and caffeine is a stimulant, which is why coffee wakes you up. Some people definitely find that drinking coffee raises their heart rate. However, on balance, most studies find that coffee drinkers tend to live longer on average than non-coffee drinkers. Coffee seems to provide important polyphenols that help to reduce inflammation, and it is also a reasonably source of soluble forms of fibre.

If the caffeine is a problem, you get most of the same benefits from decaffeinated coffee—it’s the coffee, not the caffeine per se, that’s good for you.

You can learn more about the benefits of coffee in our page on Coffee and Health.

Myth 10. Alcohol is good for you, provided you don’t drink too much

We’ve all read about the studies saying that a glass of red wine every day is good for your heart.

Red wine contains polyphenols, which are good for our gut microbiota, and may have an anti-inflammatory effect. However, the studies about red wine tend to be used to justify drinking other forms of alcohol as well, and in far higher quantities.

Unfortunately, the evidence really doesn’t stack up.

The problem is that alcohol affects far more than your heart.

In particular, drinking alcohol is a leading cause of several different types of cancer. What’s more, many of the cancers attributable to drinking alcohol were associated with drinking at a light to moderate level. There might conceivably be a level of red wine intake where the benefits from the polyphenols counterbalance the increased risk of cancer. However, it is likely to be very low—and may only apply to some people.

You can find out more about why the World Health Organization Europe has advised that there is ‘no safe level of alcohol consumption’ in our page on Alcohol and Health.