Can Eating Fast Foods Kill Your Good Gut Bacteria?

Research claims eating highly processed foods in huge portions can kill your beneficial gut bacteria. Diets composed of a relatively small number of ingredients, most of which are highly processed, are toxic to these bacteria. In fact, many of them die off within days of beginning such a processed food diet. Changes in the human body’s gut microbe community or microbiome, are likely to be responsible of the obesity epidemic and other chronic diseases such as diabetes, cancer and heart disease.


It is clear that the more diverse your diet, the more diverse your microbes and the better your health would be at any age. As we all are aware, every day we see ourselves become increasingly bewildered about what to eat.


Despite the persistent advice we get from expert dietitians about the dangers of too much fat, sugar, protein and lack of exercise, the problem related to obesity seems not to change at all. In fact, it is getting worse!


Most people probably did not know this yet, but eating highly processed foods and fast foods in huge portions may not do you any favor and can definitely interfere with your weight loss goals. British researchers found that eating fast foods may kill off your beneficial gut bacteria that help burn calories.


After only 4 days of eating fast food continually, the microbes were already suffering. Surprisingly, eating fruits and vegetables again, even after 2 weeks haven’t recovered more than 50% of the loss species.



Your gut bacteria don’t like junk food, even if you do. Keep this in mind. The healthier would be your gut bacteria and immune system, the lesser would be the probability for obesity.


Many people eat junk food on a regular basis and even if they don’t get fat from the calories, the body’s metabolism and immune system are suffering via the effects on the microbes. Binging on fast food could be one of the most effective ways to kill off the gut bacteria that keep you fit, healthy, and happy.


This strong link between the good bacteria, diet and obesity was discovered by researchers who experimented to live on fast food meals for 10 days straight. They lived on eating McDonalds for 10 days straight and found out that eating fast food and junk food kills the stomach bacteria.


A professor along with his enlisted son spent 10 days eating McDonald’s hamburgers, chips, chicken nuggets and Coca Cola. Before his son started the diet, he got about 3,500 bacterial species in his gut, dominated by a type called firmicutes.


Once on the diet, he rapidly lost 1,300 species. In addition, his gut was dominated by a group called bacteriodetes. It simply implied that the fast food diet killed 1,300 of his gut bacteria species.


You should eat meals that are natural and diverse as possible. Most processed food products are depressingly composed of just these four ingredients of corn, soy, wheat, or meat. Ditch the processed foods and start to eat healthy.



Sugar and trans fat

It is the most dangerous drug of all times and can be acquired anywhere, anytime. It is actually a 50-50 mixture of glucose and fructose, sucrose.


A normal 330 ml of cola contains about 140 calories and over 8 spoonfuls of sugar. Everyone likes sugar.


The food industry has skillfully used the word empty calories in referring to sugar, so it will come out as just pure energy rather than a major source of body fat.



Perhaps, the most dangerous kind of food is one that is hidden, and doesn’t appear on the label. More and more packaged foods are sweetened with a baffling array of sugars, which add calories without boosting nutritional value.



How do you get people to crave?

The food industry technicians and chemist set out to learn how to maximize the power of sugar in foods by designing taste tests. The inverted U graph showed that the liking of food rose as the amount of sugar increased to a certain point.


After that peak, adding more sugar was not only a waste, but it had diminished the allure of the food. Recognizing the financial potential, they created a complex of menus in different formulations to suit people of widely divergent needs and taste.


As the sensory intensity increases, consumers first say that they like the product more. Eventually, with a middle level of sweetness, consumers love the product most, which is referred to as the optimum or bliss point.


In the food industry, finding the bliss point for sugar in dinner products like pasta sauce would soon become passe. People love to eat convenient and easily prepared meals.


The food industry had identified exactly what it is about certain foods that takes us to this level of desire. The data not only served as a guide for food manufacturers to make the product alluring, they also shed light on the very underpinnings of the obesity crisis.


This is because what they found is the fact that hunger is a poor driver of cravings, but rather humans are driven to eat by other forces, such as the aroma, appearance, taste, and texture plus the emotional needs. As disparate as these pillars may seem, one ingredient can do it all – sugar!


This means one thing. No sugar, no fat, no sales. Eating a specific food is habit forming.


Fast foods make people acquire bad eating habits by formulating the taste of their products with sugar, salt, and trans fat.


It is easy to fall into a trap of developing poor eating habits. After all, they taste good. Foods that have a long term deleterious effect include those that contain saturated fats, trans fats, excessive sugar or salt and high glycemic foods that increases blood sugar, which is relatively the characteristics of fast foods.


Baked goods can contain excessive amounts of trans fats and sugar and high glycemic foods, which are generally made from refined white flour, sugar, white bread, white potatoes, and white rice.


People prefer to eat what they like rather than what is scientifically good for their health. One of the specific reasons is the environment, where people became accustomed to eating fast foods, which is also, habit forming.



How killing your gut bacteria make you fat?

The fascinating interplay between diet, gut bacteria and the gut hormones can affect the total body fat secreted mainly from the intestinal cells. The gut is not only involved in the pathogenesis of obesity, but is affected by its presence.


Recently, an altered gut microbiota has been suggested to be critical for the development of obesity. The implication has been found in numerous gastrointestinal complications and diseases ranging from GERD to colonic cancer and liver cirrhosis.


When it comes to maintaining a healthy gut, sustainability is the thing. Most diets don’t work because they can’t work. They are simply unsustainable.


Obesity is a condition of disturbed energy balance. Accumulating evidence suggests that bacteria in the intestinal tract play an important role in obesity and its related disease.


These organisms, collectively referred to as the microbiota, influence every aspect of the human health as they perform critical functions that affect immunity, metabolism, and nutritional status.


The incidence of obesity and the metabolic syndrome is assuming epidemic proportions both in developed and developing countries. This is a phenomenon that cannot be attributed to genetic factors anymore, because the human genes have not changed recently.


This simply implies that the digestive process and assimilation from the small intestine play a significant role in the amount of calories that are ultimately available to the body.


Because a major portion of digestion and assimilation of digested food occurs in the small intestine, it is quite natural that the bacteria present in this portion of the gut can impact the energy balance, and obesity.


It is no surprise that the human gut bacteria play a major role in obesity. Recent studies revealed that in obese humans, the predominant gut bacteria are the Firmicutes, which are rich in enzymes that break down hard to digest dietary polysaccharides.


This leads to a better digestion and absorption that makes the host obese. The gut microbiota is currently regarded as responsible for the weight gain and the altered energy metabolism that accompanies the obesity state.


A series of experiments have succeeded in proving the cause and effect. Alterations in the gut bacteria causes a change in the intestinal permeability that contributes to chronic metabolic conditions and especially to the development of nonalcoholic fatty liver disease.


Diet is a paramount factor in shaping the gut ecosystem. People consuming a diet of highly processed foods have been shown to have a less diverse gut flora.



Can too much salt and sugar kill your gut bacteria?

Sugar and other foods with high glycemic index value spike insulin levels and place the immune system on high alert. When blood sugar spikes, you tend to crave more sweets, starch, refined flour goods, salt, and junk food.


More cortisol production causes further inflammation and creates more cravings due to the higher insulin levels. As a result, high insulin levels activate enzymes that raise levels of arachidonic acid in the blood,


Arachidonic acid is a natural fatty acid found in certain foods and is also made in the body. It is the building block of inflammatory hormones so you don’t want it in abundance.


Consuming large amounts of sugar, fructose, artificial sweeteners and low calorie sweeteners, such as sugar alcohols cause your gut bacteria to adapt in a way that interferes with your satiety signals and metabolism.


The sweetener adapted bacteria thrive and become more efficient at processing large amounts of sugars, which result in producing more and more short chain fatty acids. The short chain fatty acids promote inflammation in the lining of the gut.


What is scary is that sometimes inflammation can be present and you will not even know it is there. This type of chronic, low grade inflammation is known as silent inflammation.


Several studies about excess sugar intake is associated with the silent type. To break this cycle, it is imperative to avoid sugar, fructose, artificial sweeteners, low calorie sweeteners, corn syrup, dextrose, pancake syrup, maltose, sorghum, and sucrose.


Too much sugar in the diet makes the body easily converts it into fat and derange the normal bacteria flora of the intestine. It is important that the intestinal bacteria be properly fed (but not overfed), because a new generation occurs about every four hours, and it is the characteristic of all bacteria to develop unsuitable and even virulent strains depending on how they are fed.




Bendich, A., & Deckelbaum, R. J. (2015). Preventive nutrition: The comprehensive guide for health professionals. Switzerland: Springer.

Fammartino, C. A. (2015). The juice lady’s anti-inflammation diet. Lake Mary, Florida: Siloam.

Kazaks, A. G., & Stern, J. S. (2013). Nutrition and obesity: Assessment, management & revolution. Burlington, MA: World Headquarters.

Moss, M. (2013). Salt, sugar, fat: How the food giants hooked us. New York: Random House Publishing.

Roberts, D. C. (2015). Fast food kills gut bacteria that can keep you slim, book claims. PBS Newshour.

Spector, T. (2015). The diet myth: Why the secret to health and weight loss is already in your gut. New York: The Overlook Press.

The Conversation. Your gut bacteria don’t like junk food – even if you do.

Williams, R. J., & Kalita, D. K. (1977). A physician’s handbook on orthomolecular medicine. New York: Pergamon Press.



The variety of species thriving in your gut bacteria are necessary for your body’s healthy functioning. Your diet can either kill or cultivate a healthy gut flora. Scientists are more concerned about modern diets suspected to be the key contributors in maintaining a healthy body weight. If you only eat right, you could have kept a good body shape with a smaller waist.


Look at those who eat primarily fast foods or processed meals, they look fatter with sagging, bulging bellies. The lack of beneficial bacteria is the main contributor to the obesity epidemic. Eating fast foods, processed foods, or junk foods kill the good bacteria in your stomach. The new study says that eating junk food kills the good bacteria responsible in keeping you stay slim.


An imbalance of bacteria in the stomach increases your chance to gain weight and develop debilitating conditions, such as colitis and inflammatory bowel diseases. Changes in the gut microbe can go against your weight loss goals. If you want to stay slim, be consistent with your diet. Eat right and take care of your good gut bacteria. Seriously speaking, you need to include healthy eating in your weight loss program.

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