Ultra-Processed Foods Are Making Us Fat and Unhealthy

In a previous post, I talked about what inspired me to do my thesis on food and cooking.  Now that it’s done and turned in, I thought I’d adapt some portions of my writing and focus on them here. One of the first, and most significant topics when talking about our food, is that of food processing. 

Scientists, doctors, nutritionists and health organizations all acknowledge that the production and consumption of processed food and drinks are important causes in the current pandemic of obesity and related chronic diseases.1

As food writer Michael Pollan so eloquently puts it, big food corporations “cook very differently from how people do (which is why we usually call what they do ‘food processing’ instead of cooking). They tend to use much more sugar, fat and salt than people cooking for people do; they also deploy novel chemical ingredients seldom found in pantries in order to make their food last longer and look fresher that it really is”.2

These novel techniques and ingredients, along with excessive amounts of sugar, fat and salt, create a diet that health professionals describe as “intrinsically nutritionally unbalanced and intrinsically harmful to health”.3

Shall I go on? OK, I will…

Carlos A. Monteiro, Director of the Center for Epidemiological Studies in Health and Nutrition at the University of Sao Paulo, proposes that the amount of processing our food undergoes is what determines how healthy or unhealthy it will be, not the food itself, nor its nutrient parts.

Across the globe, government food recommendations do not recognize this difference, and as a result, food like whole fresh fruit, fruit canned in sugary syrup and reconstituted sugary fruit beverages all get classified as “fruit”.4

Side note: A 2010 study found that the diets of nearly the entire US population did not fall within federal dietary recommendations. So, even with sugary fruit beverages being classified as fruits, we still do not meet the recommended amounts of fruits and vegetables.

Monteiro argues that most food today has some degree of processing and that there is little use in classifying food into only processed and unprocessed groups. Instead, he proposes three levels to describe the drastic differences in processing that occur between, for instance, pre-washed fruit and a gummy fruit snack.

The three categories are:

Group 1: Unprocessed and minimally processed foods:
No processing, or mostly physical processes used to make single whole foods more durable, accessible, convenient, palatable or safe.
Group 2: Processed culinary or food industry ingredients:
Extraction and purification of components of single whole foods, resulting in producing ingredients used in the preparation and cooking of dishes and meals made from Group 1 foods in homes and traditional restaurants, or else in the formulation by manufacturers of Group 3 foods.
Group 3: Ultra-processed food products:
Processing of a mix of Group 2 ingredients and Group 1 foodstuffs in order to create durable, accessible, convenient, and palatable ready-to-eat or to-heat food products liable to be consumed as snacks or desserts or replace home-prepared dishes.

The groups are described more thoroughly below (from Monteiro’s research) but it’s easy to see that foods like cookies, snacks, pre-prepared meals, processed meat like chicken nuggets and burgers all belong in Group 3.6

Montiero- food classifications
From “Food classifications based on the extent and purpose of industrial processing”. by C. Monteiro, 2010, Cadernos de saude publia, 26, p. 2042. Copyright 2010 by Carlos Monteiro.


He does not propose that healthy diets are made up of entirely unprocessed/minimally processed foods, but rather a healthy balance of the three groups.

The problem is, that across countries like Brazil, the UK and the US, we seem to completely lack the ability to maintain this balance.

In Brazil, ultra-processed (Group 3) foods made up 20% of consumed calories. As income increased, so too did the presence of these ultra-processed foods. In the households with the highest income, nearly one-third of all calories came from ultra-processed foods.7

In the UK, ultra-processed foods made up 45% caloric intake.8

In the United States, the five most commonly consumed foods were all considered Group 3 foods: sodas, cakes and pastries, burgers, pizza and potato chips. These five foods alone made up 20% of the total calories consumed in the United States.9

A similar study in Canada showed that 61.7% of dietary energy consumed came from ultra-processed foods and that 80% of the Canadian population had diets consisting of more than 50% of ultra-processed foods in terms of caloric intake.10

Yeah? So what does that mean?

Monteiro’s claim that the act of processing food is a culprit in our rapid decline in health is being confirmed more specifically in subsequent studies. One recent study showed a link between two commonly used emulsifiers and the development of metabolic syndrome and low-grade inflammation in the gastrointestinal tract of mice.11

Emulsifiers can be found in nearly all processed food and are used to prevent ingredients like fats and oils from separating. They go by many names, but some of the common ones are: polysorbate 80, lecithin, carrageenan, polyglycerols and xanthan gum. The “metabolic syndrome” that these items are linked to is a term used to describe a group of risk factors, including high levels of cholesterol, high blood pressure and high blood sugar, as well as obesity. Someone with metabolic syndrome is more likely to develop more serious health issues like type 2 diabetes and cardiovascular problems like heart attacks and strokes.12

The addition of emulsifiers is by no means the only cause of obesity, but the inflammation that it causes in the gastrointestinal tract appears to interfere with the feeling of “being full” while eating.13 Not feeling full often leads to overeating and, in turn, the development of more fat.

So what can I do about it?

Simple! First, decrease, limit and/or eliminate ultra-processed foods from what you eat. It has clear benefits in preventing disease and promoting general well being, Monteiro says.14

Second, even with the downward trend of cooking, more than two-thirds of caloric intake for adults in the US still occurs in the home.15 Therefore, the most good can be done by focusing on food and meals we consume at home.

I think these point to a clear path forward: cut down on processed foods by cooking more at home. It is one of the easiest daily acts we can do to improve our health.

Numerous studies have the same conclusion, one even suggesting that, “Efforts to boost the healthfulness of the US diet should focus on promoting the preparation of healthy foods at home while incorporating limits on time available for cooking”.16

An increase in cooking at home has been shown to relate directly to a decrease in Body Mass Index (BMI),17 and lower BMI decreases the risk other health issues like diabetes, hypertension, coronary artery disease and many types of cancer.18

So what are you waiting for? Put down the fast food and the pre-packaged meals and make your next meal from simple, fresh ingredients.

If you want to read my Masters Thesis in its entirety, you can download it in the Download section. You can also see a shorter slide show here. Enjoy!


1,3,4,14 Monteiro, C. A. (2009). Nutrition and health. The issue is not food, nor nutrients, so much as processing. Public health nutrition, 12(05), 729-731.

2 Pollan, M. (2013). Cooked: A natural history of transformation. Penguin UK.

5,15,16 Smith, S. M. K., Guenther, P. M., Subar, A. F., Kirkpatrick, S. I., & Dodd, K. W. (2010). Americans do not meet federal dietary recommendations. The Journal of nutrition, jn-110.

6,7,8,9 Monteiro, C. A., Levy, R. B., Claro, R. M., Castro, I. R. R. D., & Cannon, G. (2010). A new classification of foods based on the extent and purpose of their processing. Cadernos de saude publica, 26(11), 2039-2049.

10 Moubarac, J. C., Martins, A. P. B., Claro, R. M., Levy, R. B., Cannon, G., & Monteiro, C. A. (2013). Consumption of ultra-processed foods and likely impact on human health. Evidence from Canada. Public health nutrition, 16(12), 2240-2248.

11 Chassaing, B., Koren, O., Goodrich, J., Poole, A., Srinivasan, S., Ley, R., & Gewirtz, A. (2015). Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Nature, doi:10.1038/nature14232

12,13 Grossman, E. (2015, February 25). How Emulsifiers Are Messing with Out Guts (and Making Us Fat). Civileats.com.

17 Kolodinsky, J. M., & Goldstein, A. B. (2011). Time use and food pattern influences on obesity. Obesity, 19(12), 2327-2335.

18 Willett, W. C., Koplan, J. P., Nugent, R., Dusenbury, C., Puska, P., & Gaziano, T. A. (2006). Prevention of chronic disease by means of diet and lifestyle changes.