If you want to be fat, tired, depressed and die early from cancer, heart disease or another crippling illness, eat processed foods.
Is that scaremongering? I wish it was.
Unfortunately, science has proven that most processed foods are nasty, nasty things that shouldn’t go anywhere near are mouths.
And virtually all of us eat them every day.
Often without realising it.
“You are what you eat” is one of the most profound statements that you’ll hear.
Unfortunately, many people don’t realise how important nutrition is to our health.
If you want to live a happy, healthy life you need to pay attention to what you eat and drink.
Food is extremely powerful and eating foods we evolved to eat will make a MASSIVE difference to your life.
A proper, balanced diet has potent, drug-like effects.
In fact, if a pharmaceutical company were to produce a pill that had equivalent benefits it would transform the world’s health.
Now, there are some big, bold statements in this intro so I need to back them up…
Let’s start by looking at the problem with processed foods.
Sure, you don’t live in a cave (I may be presumptuous here!) but genetically-speaking we are still cavemen1.
We evolved over millions of years eating particular foods.
About 10,000 years ago the agricultural revolution began and the our diet changed radically.
From an evolutionary perspective 10,000 years is the blink of an eye and certainly not sufficient time for us to evolve to cope with a drastically changed diet.
Before the agricultural revolution we were hunter-gatherers eating foods that could be hunted or fished (meat, fish, shellfish, etc) and foods that could be gathered (vegetables, fruit, nuts, seeds, eggs, mushrooms, herbs, spices, etc).
These were, of course, all wild and organic so were full of nutrients and free from chemicals.
During the agricultural revolution we began to rear animals for meat and to grow various crops, including grains.
This is where the problems began.
Things got worse during the industrial revolution when foods were processed and refined and the use of chemical fertilisers and pesticides became prevalent.
In the today’s world our diet is very different from the diet of our ancestors.
In the US, the acronym “S.A.D.” has been coined; it stands for Standard American Diet!
It isn’t just a US issue though.
The food eaten in most countries has changed dramatically, even over the last 200 years.
For example, food used to be fresh and grown locally but these days much of it is processed, contains excessive amounts of sugar together with toxic fats and chemical additives.
The result of this is inflammation that slowly damages our bodies and causes a host of chronic diseases.
Of course, virtually all food is processed in some way before we eat it so let’s be 100% clear on what we mean.
What I am talking about here is overly processed foods that have been highly refined with the result that their intrinsic nutritional value has been removed and/or chemicals (preservatives, flavourings, colourings, etc) have been added.
Problem is, our brains LOVE processed foods.
As we talked about in our post 14 Science-backed hacks to lose weight fast (without even trying), we evolved from times when food could be scarce and so calorie dense foods were a great aid to survival.
Highly processed foods tend to be packed with fat and sugar which means they are very calorie dense but our brains haven’t evolved to recognise that we are no longer in a struggle for survival.
So, we crave them. This often leads to overconsumption2 and can lead to addiction3.
Our love of processed foods is a problem because they are often high in refined carbohydrates, low in nutrients, high in calories, low in fiber, high in trans fats and packed with chemicals.
Each of these causes health issues.
There are not that many studies on the health effects of “processed foods” as a category because the constituents differ substantially.
Instead researchers have looked into the effect of specific ingredients. We’ll look at these below.
In the studies that have been done, processed foods have been linked with an increased risk of cancer4, asthma, eczema and severe allergic reactions5.
Sugar – the sneaky ingredient hidden in processed foods
Sugar is bad for you.
But you probably already know that! What you may not know is that it is often sneaked in to processed foods.
I’m not talking about the natural sugars that are found in fruit and vegetables here. I’m talking about the stuff that has been heavily processed and refined.
The problems come from the fact that we are simply not designed to process large amounts of sugar.
We can’t deal with it efficiently because we haven’t evolved to do so.
But it gets worse.
Over the years the amount of sugar we eat has increased dramatically.
One study, for example, showed that in 1700 the average sugar consumption per year was 1.8kg (4lbs) but by 2007 had reached over 67kg (147lbs) per year6!
So, what is the consequence of this massive increase?
Well it’s not great for our teeth7 but that’s a minor issue in the scheme of things.
Excessive sugar intake has been shown to cause liver damage8, diabetes9, obesity10, cancer11 12 13 and heart disease14.
To make matters even worse, it is highly addictive15.
It is not just sucrose – the most common form of sugar – that is the problem; sugar comes in many forms and is often hidden in products.
Various names are used to describe it. Here are the most common:
And it’s not just these “pure” forms of sugar that cause problems.
Refined carbs are not much better.
Refined carbs are carbohydrates that have been heavily processed so that the fibre and nutrition has been removed. Most often they come from grains like wheat.
Common examples of refined carbs include bread, pasta, rice, white flour, foods containing white flour and white potatoes.
By removing the fibre, we’re losing a key substance that protects against heart disease, obesity, type 2 diabetes and cancer16 17 18.
But, not only do we lose something that has a protective effect, refined carbs in themselves actually increase our risk of obesity19, heart disease20, diabetes21, depression22 and cancer23.
You can download our checklist “How to avoid processed foods” for a quick and easy guide to identify processed foods below.
Gluten is another nasty ingredient that is often hidden in processed foods.
It is found in many grains (including wheat, barley, rye, semolina, and couscous but not buckwheat, quinoa, rice, corn or millet) and contains chemicals called lechtins.
These are the grains’ self-defensive mechanism against being eaten.
The problem with gluten is that we have not evolved with the stomach enzymes necessary to digest it properly.
When we eat gluten inflammatory particles are released into our bloodstream and transported around our body.
The consequence can then be gluten sensitivity and Celiac disease (an extreme reaction to gluten) which have in turn been linked with irritable bowel syndrome, cancer, fatigue24, schizophrenia25, depression26 and dementia27.
Gluten consumption has also been linked with increased risk of dying early.
For example, a study28 of nearly 30,000 patients over 40 years looked at death rates of people with Celiac disease and gluten sensitivity.
The researchers found a 39% increased risk of dying early in patients with Celiac disease, a 72% increased risk in those with gut inflammation related to gluten and a 35% increased risk in those with gluten sensitivity but no Celiac disease.
Make no mistake, eating gluten is an issue.
What makes things worse is that gluten issues are difficult to test for.
So, whilst around 0.5-1%29 of people have been found to have Celiac disease, it is estimated that 29%30 of us experience issues with gluten.
One study31 suggests that the numbers are actually increasing rapidly: comparing blood tests taken from a group of people between 1948 and 1954 and tests from people 50 years later researchers found a 400% increase in the incidence of Celiac disease!
Omega 6, omega 3’s dangerous cousin
Processed foods often contain high levels of oils and fats that have been produced using heavy chemical processes.
These oils are unlike anything we have been exposed to throughout evolution.
This isn’t a compliment to human ingenuity as they are extremely damaging to our health.
The first problem is trans fats.
I’m not going to cover them here except to say that they are so damaging to our health that I’ve included them in their own section.
Another problem is the type of fats contained in refined oils.
You have probably heard of omega 3 fats and the health benefits of consuming them.
Fewer people will have heard of omega 6 fats.
In themselves there is nothing wrong with omega 6 fats; they are known as an “essential” fat meaning that our body can’t produce them itself. We have to get them from our food.
The issues arise when the balance between omega 6 and omega 3 intake gets out of kilter.
As humans evolved, we typically consumed a 1:1 ratio of omega 6s to omega 3s32.
Today the ratio is around 16:133!
The position is even more skewed than this ratio suggests because these fats compete with each other so the more omega 6s we eat the more omega 3s we need34.
So, what’s the problem?
When the ratio is out of kilter omega 6s cause chronic inflammation and chronic inflammation is linked to numerous diseases.
For example, excessive omega 6 intake has been linked with heart disease35, asthma36, cancer37 and depression38.
Nasty, nasty trans fats
Trans fats are bad news and should be avoided by everyone.
End of story.
Trans fats are a specific type of heavily processed oil that has been linked with a host of health problems including brain deterioration39, diabetes40, obesity41, Alzheimer’s disease42, depression and heart disease43.
They have also been shown to increase the chance of dying early from any cause by 34%44!
Trans fats are cheap and have a long shelf life so are widely used.
They are so damaging to health that some countries have effectively banned their use.
Processed foods supersize you
It’s probably no surprise given the sections on sugar and oils that many of us eat too many calories.
These are not the only causes however; increased food availability and more aggressive marketing have also been blamed.
Various studies have estimated how much calorie intake has increased over the years with one study45 suggesting that adults eat an additional 500 calories per day.
It is interesting to note that levels of obesity have increased alongside the caloric increase46.
Let’s start by getting one thing straight: wild and organic meat reared in the way nature intended and eaten in moderation is not the issue here.
The issue is meat from animals that have been raised in artificial conditions, fed foods they do not naturally eat, given drugs to keep them free of disease and, in some countries, given hormones to speed up growth.
This is the type of meat most often found in processed foods.
Take beef as an example.
Nature intended for cattle to roam pastures and graze on grass.
They are not intended to be intensively reared, kept in a confined cowshed, be fed a grain-based diet and receive antibiotics, growth hormones and other drugs.
Cattle reared in this way produces very different meat to cattle raised naturally.
And the difference is not a good one.
Unfortunately, the vast majority of beef is now produced in this way. In the US it is known as “feedlot”.
The saying “you are what you eat” is again very relevant here.
By eating meat raised in an unnatural way we ourselves are eating food that we are not by evolution designed to eat.
And guess what?
This can lead to health problems.
You have no doubt seen news headlines that report on studies that proclaim red meat causes various illnesses.
One of the things that these studies don’t do is differentiate between naturally reared meat and intensively reared meat.
Naturally reared meat is a very different beast (pun intended!).
However, the results of these studies are still valid because the vast majority of red meat consumed is intensively reared.
On the other hand, using beef again as the example, naturally raised, grass-fed beef has been shown to have:
Rather than causing health issues, grass-fed beef is good for us.
Whilst the example above refers specifically to beef, the position is similar with other naturally reared meats52 53 54 55 56.
So, that’s red meat.
What about processed meat?
By processed meat, I mean meat that has been processed through salting, curing, fermentation, smoking or any other process used to enhance flavour or improve preservation.
Examples include hotdogs, ham, sausages, bacon, corn beef, jerky, canned meat and meat found in processed food.
Here, the position is clear:
The World Health Organisation has stated unequivocally that processed meat causes certain types of cancer.
They have classified it as carcinogenic to humans. In fact, just one hot dog or a few slices of bacon a day increases colorectal cancer risk by 18%57.
The World Cancer Research Fund and the American Institute for Cancer Research share the same view58:
“the evidence on processed meat and cancer is clear cut”
One study59 found that eating just 50g (less than 2oz) of processed meat a day causes an 8% increased risk of dying from cancer and increases your chances of getting the following illnesses:
Death from heart disease
Another study60 of 200,000+ women found that eating less than half a hot dog (20g or less than 1oz) increases your chances of getting breast cancer by 21%.
But, eating processed meat doesn’t just increase our risk of cancer.
Another massive study61 found that eating too much processed meat was linked to an increase in our chances of getting heart disease, suffering a stroke and developing type 2 diabetes.
In fact, it concluded that eating processed meat was tied to 57,766 deaths in the US in 2012.
So, how do we avoid processed foods?
It’s not easy.
Many of the ingredients we’ve talked about are hidden away using different names.
One option is to cross-check every ingredient for each thing we buy but who has the time to do that?!
Instead, here are some simple hacks to help you avoid processed foods:
It’s also helpful to know which everyday things are actually processed foods so here are the 32 most common:
Bread and baked goods
Dried fruit (unless organic)
Food with added sugar
Gluten-free junk foods
Low-carb junk foods
Margarine and butter substitutes
Processed meats, including bacon, hot dogs, sausages and deli meat
Ready-made sauces, including ketchup and salad dressing
Refined oils, including canola oil, corn oil, soybean oil, “vegetable” oil, peanut oil, groundnut oil, sunflower oil, safflower oil, cottonseed oil, grapeseed oil
Sweetened coffee drinks
Processed foods are dangerous.
2 Common cellular and molecular mechanisms in obesity and drug addiction. Nat Rev Neurosci. 2011 Oct 20;12(11):638-51
3 From Passive Overeating to “Food Addiction”: A Spectrum of Compulsion and Severity. ISRN Obesity Volume 2013 (2013), Article ID 435027
4 Processed meat and colorectal cancer: a review of epidemiologic and experimental evidence. Nutr Cancer. 2008; 60(2): 131–144
5 Do fast foods cause asthma, rhinoconjunctivitis and eczema? Global findings from the International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three. Thorax. 2013 Apr;68(4):351-60
6 Potential role of sugar (fructose) in the epidemic of hypertension, obesity and the metabolic syndrome, diabetes, kidney disease, and cardiovascular disease. Am J Clin Nutr October 2007 vol. 86 no. 4 899-906
7 Sugars and dental caries. Am J Clin Nutr October 2003 vol. 78 no. 4 881S-892S
8 Long term nutritional intake and the risk for non-alcoholic fatty liver disease (NAFLD): A population based study. J Hepatol. 2007 Nov;47(5):711-7
9 Sugar-Sweetened Beverages, Weight Gain, and Incidence of Type 2 Diabetes in Young and Middle-Aged Women. JAMA. 2004;292(8):927-934
10 Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity. Am J Clin Nutr April 2004 vol. 79 no. 4 537-543
11 Diet and breast cancer: The possible connection with sugar consumption. Medical Hypotheses Volume 11, Issue 3, July 1983, Pages 319-327
12 Sugar, meat, and fat intake, and non-dietary risk factors for colon cancer incidence in Iowa women (United States). Cancer Causes & Control January 1994, Volume 5, Issue 1, pp 38–52
13 Dietary sugar and colon cancer. Cancer Epidemiology Biomarkers and Prevention. September 1997 Volume 6, Issue 9
14 Sweetened beverage consumption and risk of coronary heart disease in women. Am J Clin Nutr April 2009 vol. 89 no. 4 1037-1042
15 From Passive Overeating to “Food Addiction”: A Spectrum of Compulsion and Severity. ISRN Obesity Volume 2013 (2013), Article ID 435027
16 Health benefits of dietary fiber. Nutr Rev. 2009 Apr;67(4):188-205
17 Dietary fiber–adequate intake and effects on metabolism health. Arq Bras Endocrinol Metabol. 2013 Aug;57(6):397-405
18 Position of the American Dietetic Association: health implications of dietary fiber. J Am Diet Assoc. 2002 Jul;102(7):993-1000
19 Excessive refined carbohydrates and scarce micronutrients intakes increase inflammatory mediators and insulin resistance in prepubertal and pubertal obese children independently of obesity. Mediators Inflamm. 2014;2014:849031
20 Dietary carbohydrates, refined grains, glycemic load, and risk of coronary heart disease in Chinese adults. Am J Epidemiol. 2013 Nov 15;178(10):1542-9
21 Increased consumption of refined carbohydrates and the epidemic of type 2 diabetes in the United States: an ecologic assessment. Am J Clin Nutr. 2004 May;79(5):774-9
22 High glycemic index diet as a risk factor for depression: analyses from the Women’s Health Initiative. Am J Clin Nutr. 2015 Aug; 102(2): 454–463
23 Dietary glycemic index and glycemic load and risk of colorectal cancer: results from the EPIC-Italy study. Int J Cancer. 2015 Jun 15;136(12):2923-31
24 Celiac disease and recurrent aphthous stomatitis: a report and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002;94(4):474-478
25 Coeliac disease and risk of schizophrenia and other psychosis: a general population cohort study. Scand J Gastroenterol. 2007 Feb;42(2):179-85
26 Coeliac disease and risk of mood disorders–a general population-based cohort study. J Affect Disord. 2007 Apr;99(1-3):117-26. Epub 2006 Oct 6
27 Cognitive impairment and celiac disease. Arch Neurol. 2006 Oct;63(10):1440-6
28 Small-intestinal histopathology and mortality risk in celiac disease. JAMA. 2009 Sep 16;302(11):1171-8
29 NIH Consensus Development Conference on Celiac Disease. NIH Consensus and State of the Science Statements. 2004;21:1–23
31 Increased prevalence and mortality in undiagnosed celiac disease. Gastroenterology 2009 Jul;137(1):88-93
32 Polyunsaturated fatty acids in the food chain in the United States. Am J Clin Nutr January 2000 vol. 71 no. 1 179S-188S
33 The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomedicine & Pharmacotherapy Volume 56, Issue 8, October 2002, Pages 365–379
34 Healthy intakes of n−3 and n−6 fatty acids: estimations considering worldwide diversity. Am J Clin Nutr June 2006 vol. 83 no. 6 S1483-1493S
35 Corn Oil in Treatment of Ischaemic Heart Disease. Br Med J. 1965 Jun 12; 1(5449): 1531–1533
36 Breast milk fatty acids and allergic disease in preschool children: The Prevention and Incidence of Asthma and Mite Allergy birth cohort study. J Allergy Clin Immunol. 2006 Feb;117(2):440-7
37 Opposing effects of dietary n-3 and n-6 fatty acids on mammary carcinogenesis: The Singapore Chinese Health Study. Br J Cancer. 2003 Nov 3;89(9):1686-92
38 Depressive Symptoms, omega-6:omega-3 Fatty Acids, and Inflammation in Older Adults. Psychosomatic Medicine: April 2007 – Volume 69 – Issue 3 – pp 217-224
39 A Fat to Forget: Trans Fat Consumption and Memory. PLoS ONE 10: e0128129
40 Diet and risk of Type II diabetes: the role of types of fat and carbohydrate. Diabetologia 44 (7): 805–817
41 Why fast foods are bad, even in moderation. New Scientist. 9 January 2007
42 Dietary fats and the risk of incident Alzheimer disease. Arch Neurol 60 (2): 194–200
43 Trans fatty acids: are the effects only marginal? American Journal of Public Health 85 (3): 411–412
44 Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies. BMJ 2015; 351
45 Estimating the changes in energy flux that characterize the rise in obesity prevalence. Am J Clin Nutr. 2009 Jun;89(6):1723-8
46 Mean body weight, height, and body mass index: United States 1960-2002. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics, 2004
47 A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutr J. 2010; 9: 10
48 Conjugated linoleic acid. A powerful anticarcinogen from animal fat sources. Cancer. 1994 Aug 1;74(3 Suppl):1050-4
49 A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutr J. 2010; 9: 10
50 A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutr J. 2010; 9: 10
51 Effects of conventional and grass-feeding systems on the nutrient composition of beef. Journal of Animal Science 2008 86: 12: 3575-3585
52 Effect of ewe feeding system (grass v. concentrate) on intramuscular fatty acids of lambs raised exclusively on maternal milk. Animal Science, Volume 81, Issue 3, December 2005, pp. 431-436
53 Effect of grass vs. concentrate feeding on the fatty acid profile of different fat depots in lambs. Eur. J. Lipid Sci. Technol., 107: 737–745
54 Pasture-based systems for poultry production: Implications and perspectives. World’s Poultry Science Journal 67(01):47 – 58 • March 2011
55 Influence of finishing diet on fatty acid profiles of intramuscular lipids, triglycerides and phospholipids in muscles of the Iberian pig. Meat Science, Volume 45, Issue 2, February 1997, Pages 263-270
57 IARC Monographs evaluate consumption of red meat and processed meat. International Agency for Research on Cancer, World Health Organisation, Press Release No 240, 26 October 2015
58 Limit red and processed meat. World Cancer Research Fund and the American Institute for Cancer Research Recommendations
59 Potential health hazards of eating red meat. J Intern Med. 2017 Feb;281(2):106-122
60 Red and processed meat consumption and breast cancer: UK Biobank cohort study and meta-analysis. Eur J Cancer. 2018 Feb;90:73-82
61 Association Between Dietary Factors and Mortality From Heart Disease, Stroke, and Type 2 Diabetes in the United States. JAMA. 2017 Mar 7;317(9):912-924