The Western Pattern Diet, impact on Human Metabolic Health and Microbiome

The Western Pattern Diet, impact on Human Metabolic Health and Microbiome

The Western Pattern Diet (WPD, also known as Standard American Diet, SAD)  is a modern dietary pattern that is generally characterized by high intakes of processed food meaning: pre-packaged foods, refined grains, processed meat, high-sugar drinks, candy and sweets, fried foods, high-fructose corn syrup... and low intakes of fruits, vegetables, whole grains, pasture-raised animal products, fish, nuts, and seeds.

But what exactly is processed food? For that matter, what is minimally processed food or ultra-processed food?

Unprocessed or minimally processed foods are whole foods in which the vitamins and nutrients are still intact. The food is in its natural (or nearly natural) state. These foods may be minimally altered by removal of inedible parts, drying, crushing, roasting, boiling, freezing, or pasteurization, to make them suitable to store and safe to consume. Unprocessed or minimally processed foods would include carrots, apples, raw chicken, melon, and raw, unsalted nuts.

Processing changes a food from its natural state. Processed foods are essentially made by adding salt, oil, sugar, or other substances. Examples include canned fish or canned vegetables, fruits in syrup, and freshly made breads.

Some foods are highly processed or ultra-processed. They most likely have many added ingredients such as sugar, salt, fat, and artificial colors or preservatives. Ultra-processed foods are made mostly from substances extracted from foods, such as fats, starches, added sugars, and hydrogenated fats. They may also contain additives like artificial colors and flavors or stabilizers. Examples of these foods are frozen processed meals, soft drinks, hot dogs and cold cuts, fast food, packaged cookies, cakes, and salty snacks.

How does (highly) processed food affect our health?

Compared to the "prudent pattern diet", which has higher proportions of "fruit, vegetables, whole grains, and poultry", the Western Pattern Diet (WPD) is associated with higher risks of cardiovascular disease and obesity. Through the course of the last several decades, the rate of obesity has progressively increased and is now one of the leading causes of death worldwide. The World Health Organization reports 1.9 billion adults were overweight in 2016. and 650 million were considered obese.

Several factors have been attributed to this epidemic with the Western Pattern Diet (WPD) considered to be a major contributor to the growing rate of obesity in the modern world. Although current lifestyle trends emphasize the importance of eating healthy, we continue to see processed foods high in added fat and sugar as major components of the Western Pattern Diet (WPD) which has corresponded to the steady rise in obesity. Western dietary habits, which are characterized by high intakes of calories due to high abundance of processed foods and drinks have been linked with higher risk of obesity, diabetes, cancer, and cardiovascular disease.

The typical Western Pattern (Standard American) diet is low in fibers, fruits and vegetables, and usually is defined by large portions, high calories, and excess sugar. Mentioned excess of added sugar accounts for more than 13% of the daily caloric intake with beverages constituting 47% of these added sugars. Other sources include pastry - cookies, cakes, and candy.

Although fruits and vegetables contain non harmful natural sugars, they as well provide beneficial nutrients such as vitamins, minerals, and antioxidants while added sugars only contribute calories. The western diet is also noted to be high in saturated and trans fats.

Potential downsides:

Nowadays, modern societies are exposed to a “Western lifestyle,” which is characterized by an excessive intake of energy-dense foods rich in added sugars and salt and a wide range of processed and ultra-processed foods, along with lack of exercise that promote an inflammatory state. This low grade inflammation may trigger the development of several disorders, such as obesity, metabolic syndrome, cardiovascular diseases, and colorectal cancer.

Abundant saturated and trans fats content not only contribute in more calories consumed; they increase low-density lipoproteins leading to atherosclerosis. There has recently been increasing interest in the effect of dietary patterns on the immune system - western diet leads to higher levels of inflammation resulting in worse health outcomes.

Individuals who are obese or overweight are at a higher risk of developing chronic illnesses such as type 2 diabetes, cardiovascular disease, hypertension, hyperlipidemia, sleep apnea, or cancer. In fact, half of all Americans have a preventable chronic illness. According to the American Heart Association, 81 million American adults have cardiovascular disease which includes coronary artery disease or cerebrovascular disease. One-third of American adults have hypertension and more than 85% of patients with type 2 diabetes are considered overweight.

Microbiota impact:

Next to all mentioned factors, western diet present devastation effect on our gut microbes too. The excess of processed foods and calorie intake characteristic for modern dietary and lifestyle habits has been linked to intestinal dysbiosis, obesity and several metabolic diseases, including diabetes mellitus type II, NAFLD and cardiovascular diseases.

Highly processed diet induces dysbiosis that leads to intestinal barrier alterations. It stimulates the production of SRB (sulphate reducing bacteria). The high concentration of sulfide produced by particular SRB is having a key role in mucus layer stability and mucosal repair - increasing gut inflammation, colitis scores and IBD.

Food and nutrients variety is crucial for microbiota diversity! Every dietary restriction leads to reduced diversity and gut health. It is so even with generally considered healthy plant-based diet! In scientific paper, when English people on a strictly vegetarian diet were studied, their microbiota resembled those of people on a Western diet more than the microbiota of other vegetarian people from different continents - due to consuming dominantly processed vegetarian food, characterized with less variety!


Modern Western Pattern Diet rich in highly/ultra processed food is literally a killing machine. You should avoid it at all costs. When we in Cidrani speak about reccomendations, essential three applicable for everyone would be:

1. avoid highly and ultra-processed food and eat variety of unprocessed or minimally processed food.

2. avoid foods and drinks that cause strong blood sugar spikes (usually but not always highly processed foods and all sugary drinks), or combine ingredients to prevent them (protein and apple cider vinegar in meals are most common tools).

3. improve microbiota diversity - consume fermented daily! But remember, it will not save you if you practice Western Pattern diet, nothing can!