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How Refrigerators Make us Fat

This article explores the history of probiotic foods, highlighting their origins in accidental fermentation and their evolution as a food preservation technique. The human gut and gut flora have developed a symbiosis with probiotic foods, which may have implications for gut health and weight management. Technological advancements like canning and refrigeration led to a decline in probiotic consumption, potentially contributing to the obesity epidemic. Embracing probiotic-rich foods could help address modern health challenges related to gut health and obesity.

How Refrigerators Make us Fat

A Journey Through the History of Probiotic Foods


Bacteria and yeast are ubiquitous in nature, playing significant roles in various ecosystems, including human nutrition. Over time, humans have harnessed the power of these microorganisms to develop fermented foods that are rich in probiotics. This journey through the history of probiotic foods will explore their origins, evolution, and impact on human health.

The Inadvertent Discovery of Fermentation

In ancient times, people were often unaware of the role microorganisms played in the fermentation process. They likely consumed fermented foods without fully understanding the mechanisms behind their production. As societies evolved, humans gradually began to harness fermentation as a food preservation technique, giving rise to an array of probiotic-rich foods.

Ancient Fermented Foods and Archaeological Evidence

Archaeological evidence suggests that humans have been consuming fermented foods for thousands of years. In 7000 BC, Neolithic communities in the Fertile Crescent were found to be producing and consuming alcoholic beverages made from fermented barley, rice, and honey (McGovern et al., 2004). There is also evidence of fermented dairy products, such as yogurt and cheese, in Mesopotamia and ancient Egypt (Farnworth, 2008).

While archaeological evidence for certain fermented foods is scarce, experts can make informed speculations based on available information. For example, it is believed that the Chinese were fermenting cabbage, cucumbers, and other vegetables as early as 6000 BC (Pérez-Díaz et al., 2017).

Early Food Preservation Techniques

In ancient times, food preservation techniques were limited to methods such as salting, drying, and fermentation. Salting and drying were used to remove moisture from foods, inhibiting the growth of spoilage microorganisms. Fermentation, on the other hand, relied on the activities of beneficial bacteria and yeast to convert sugars into acids, alcohols, and gases, preserving the food while also enhancing its flavor and nutritional value.

The Neolithic Period and the Rise of Deliberate Fermentation

The Neolithic period, marked by the advent of agriculture, saw a significant increase in the production and consumption of fermentable foods. As societies became more reliant on farming, they began to store and preserve larger quantities of grains, fruits, and vegetables. This shift likely led to the intentional development of fermented foods, as people sought ways to prolong the shelf life of their harvests.

Ancient Recipes and Probiotic Diets

The ancient world was rich in fermented foods, many of which are still consumed today. For example, garum, a fermented fish sauce, was a popular condiment in ancient Rome (Grainger, 2006). Other examples include kimchi in Korea, miso in Japan, and sauerkraut in Germany.

The human gut and gut flora have evolved symbiotically with probiotic foods, with evidence suggesting that a significant portion of the ancient diet was probiotic (Sonnenburg & Sonnenburg, 2014). This close relationship between the human gut and probiotic foods has shaped our digestive system and overall health in ways that are still being explored today.

Probiotic Foods Around the World

Throughout history, diverse cultures have developed unique probiotic foods. Some examples include kefir in the Caucasus Mountains, kombucha in China, and tempeh in Indonesia. These foods not only provided essential nutrients but also promoted gut health and overall well-being.

The Decline of Probiotic Consumption and the Obesity Epidemic

The invention of canning in 1809 by Nicolas Appert marked a turning point in food preservation, as it allowed for the long-term storage of foods without the need for fermentation. The widespread adoption of refrigeration in the 1920s further contributed to the decline of probiotic consumption in Western society. These technological advancements, while improving food safety and convenience, inadvertently disrupted the balance of gut flora and its symbiotic relationship with probiotic foods.

Numerous studies have demonstrated a connection between probiotic consumption, gut flora, and obesity (Tilg & Kaser, 2011). It has been theorized that the decline in probiotic consumption due to canning and refrigeration may have contributed significantly to the obesity epidemic that emerged in the 20th and 21st centuries.

The Science of Probiotics, Gut Flora, Inflammation, and Weight

Current research is delving deeper into the role of probiotics, gut flora, inflammation, and weight. Probiotics have been shown to improve gut health by increasing the diversity of beneficial bacteria, promoting a healthy gut barrier, and modulating the immune system (Hill et al., 2014). These effects can reduce chronic inflammation, which has been linked to obesity and related metabolic disorders.

Studies have also demonstrated that altering the gut microbiota through probiotic supplementation can have a positive impact on weight management and metabolic health (Borgeraas et al., 2018). The growing body of evidence supporting the benefits of probiotics is leading to a resurgence of interest in fermented foods and their potential role in addressing the obesity epidemic.


The history of probiotic foods is a testament to the resilience and adaptability of human cultures and their symbiotic relationship with the microbial world. From the inadvertent discovery of fermentation to the deliberate harnessing of its power, the journey of probiotic foods has been marked by innovation and evolution.

As we gain a deeper understanding of the intricate connections between probiotics, gut health, and weight management, it is becoming increasingly clear that returning to our roots and embracing probiotic-rich foods may hold the key to addressing modern health challenges.


Borgeraas, H., Johnson, L. K., Skattebu, J., Hertel, J. K., & Hjelmesaeth, J. (2018). Effects of probiotics on body weight, body mass index, fat mass and fat percentage in subjects with overweight or obesity: a systematic review and meta-analysis of randomized controlled trials. Obesity Reviews, 19(2), 219-232.

Farnworth, E. R. (2008). Handbook of Fermented Functional Foods (2nd ed.). CRC Press.

Grainger, S. (2006). Cooking Apicius: Roman Recipes for Today. Serif.

Hill, C., Guarner, F., Reid, G., Gibson, G. R., Merenstein, D. J., Pot, B., Morelli, L., Canani, R. B., Flint, H. J., Salminen, S., Calder, P. C., & Sanders, M. E. (2014). Expert consensus document: The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology, 11(8), 506-514.

McGovern, P. E., Zhang, J., Tang, J., Zhang, Z., Hall, G. R., Moreau, R. A., Nunez, A., Butrym, E. D., Richards, M. P., Wang, C. S., Cheng, G., Zhao, Z., & Wang, C. (2004). Fermented beverages of pre- and proto-historic China. Proceedings of the National Academy of Sciences, 101(51), 17593-17598.

Pérez-Díaz, I. M., Breidt, A., Buescher, J., & McFeeters, R. F. (2017). Fermented and acidified vegetables. In Compendium of Methods for the Microbiological Examination of Foods (5th ed., pp. 877-884). American Public Health Association.

Sonnenburg, J. L., & Sonnenburg, E. D. (2014). Gut reactions: How the microbiota you inherited shapes your gut microbiome. Science, 346(6211), 1251106.

Tilg, H., & Kaser, A. (2011). Gut microbiome, obesity, and metabolic dysfunction. The Journal of Clinical Investigation, 121(6), 2126-2132.

Further Reading

Cani, P. D. (2018). Human gut microbiome: hopes, threats and promises. Gut, 67(9), 1716-1725.

Marco, M. L., Heeney, D., Binda, S., Cifelli, C. J., Cotter, P. D., Foligné, B., Gänzle, M., Kort, R., Pasin, G., Pihlanto, A., Smid, E. J., & Hutkins, R. (2017). Health benefits of fermented foods: microbiota and beyond. Current Opinion in Biotechnology, 44, 94-102.

Suez, J., Zmora, N., Segal, E., & Elinav, E. (2019). The pros, cons, and many unknowns of probiotics. Nature Medicine, 25(5), 716-729.

These references offer a comprehensive understanding of the history, cultural significance, and health implications of probiotic foods. Delving into the complex relationship between the human gut, gut flora, and obesity, these resources will help you appreciate the importance of probiotics and the potential role they can play in addressing contemporary health issues.


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