On any given day, an estimated 36.6% of the U.S adults or 84.8 million consume junk food (1). Fast food is greasy, high in calories, abundant in salt, and poses a huge threat to your health. Greasy foods seem to be omnipresent and their appeal lies primarily in a convenient price and ease of preparation. 

Reasons to avoid junk food, particularly fried and cooked with excess oils are numerous. While French fries, cheeseburgers, onion rings, and other similar foods may seem affordable and delicious, you need to avoid them in order to protect your health and quality of life. In this post, you’re going to learn more about all the negative effects of greasy food.

Weight Gain and Obesity

According to the CDC, the age-adjusted prevalence of obesity in U.S. adults was 42.4% (2) and there is no huge difference between men and women. The rates of overweight and obesity increase with a sedentary lifestyle and Western diet. The term Western diet refers to a modern dietary pattern that includes a high intake of pre-packaged, fried, and other fast and unhealthy foods as well as processed meat. This eating pattern has no nutritional value. It doesn’t supply the body with nutrients it needs to function properly. 

Unhealthy food preparation methods such as deep-frying make you eat too many calories without even realizing it at first. For instance, 3.5oz (100g) of baked potato contains 93 calories and 0.1g of fat (3) while the same amount of French fries delivers 312 calories and 15g of fat (4). As you can see, the difference in calorie load between the same amounts of potatoes, prepared in a different way, is massive.

Since greasy foods are high in calories they may lead to weight gain if you consume them on a regular basis. You see, weight gain happens when you consume more calories than you burn. The relationship between greasy food and weight gain is scientifically proven. Children (5) and adults (6, 7) alike are prone to gaining weight when they consume fast and fried foods. The more you eat these types of food, the higher the risk of overweight and obesity. On the other hand, decreasing the intake of greasy foods can promote weight loss (8).

When we’re talking about greasy foods, it’s important to clarify one thing – not all dietary fat is equal. Some types of fat are, actually, healthy for you while others are not. Trans fats are mainly present in fast food and they can wreak havoc on your health. The chemical in vegetable oils that keeps them solid at room temperature forms trans fats. These unhealthy fats are inexpensive and easy to obtain, which is exactly why companies use them all the time. 

By avoiding greasy foods, especially trans fats, you’ll be able to slim down or maintain weight in a healthy range. 

Nutritional Deficiencies

A nutritional deficiency happens when the body fails to absorb the necessary amount of a certain nutrient or more of them. The body needs a wide range of vitamins, minerals, amino acids, and other nutrients to function properly. Deficiencies lead to various health problems, but they’re avoidable. 

Consumption of greasy and fast foods is associated with an excessive intake of undesirable nutrients such as too much sodium, sugar, saturated, and trans fats. At the same time, it deprives the body of desirable nutrients like vitamins and minerals (9).

A common misconception is that eating fruits and vegetables is enough to obtain the nutrients they have. But it all comes down to how you prepare them. Unhealthy cooking methods such as frying and using too much oil decrease the nutritional value of produce. As a result, you’re at a higher risk of nutritional deficiencies and the dangers they carry. 

Faster Aging Process

Aging is an inevitable process, but some factors accelerate it. An unhealthy lifestyle is the main culprit for faster aging and diet plays a major role here. Foods you eat have a direct impact on the functions of cells and the skin. A diet abundant in oils, fats, sugars, and starches ages you more quickly. Eating three or more servings of these foods a day is associated with shorter telomeres, chromosome structures that mark your biological age (10). 

This isn’t just about your skin, but cells, tissues, and organs that are more likely to experience age-related problems. 

Since it’s human nature to look for a way to slow down the aging process, it would be difficult or even impossible to achieve it with greasy food consumption. 

Gastrointestinal Problems

Did you know that fat is the most slowly digested macronutrient (11)? It takes a lot longer for the body to break down fat compared to other macronutrients such as carbohydrates and protein. This is exactly why fat is so complex and you need to be careful about how much you consume, especially if you eat unhealthy greasy foods.

Since greasy foods are laden in fat, they may slow down the emptying of your stomach. As a result, you’re more prone to gastrointestinal problems such as nausea, abdominal pain, and bloating (12).

The problem becomes even worse for people with digestive complaints such as irritable bowel syndrome (IBS). Evidence shows that the avoidance of fatty foods is one of the most frequent approaches for the treatment of IBS. Grease or fat in foods inhibits small bowel motility, impairs intestinal gas clearance, and induces gas retention and bloating (13). 

In a nutshell, greasy foods can worsen symptoms of digestive problems including diarrhea, abdominal cramps, and pain. Even if you don’t have IBS, you can still experience bloating or even constipation due to the damaging effects of too much fat on your digestive system.

Impaired Gut Microbiome

The term gut microbiome refers to microorganisms, viruses, bacteria, and other material present in your gastrointestinal tract. Your health depends on the balance of these microorganisms in gut microbiota. In fact, the gut microbiome takes part in various important functions including metabolism, weight regulation, heart health, gut health, mental health, and immune system. 

Both good and bad bacteria are present in your gut. Their balance maintains the function of the immune system and keeps you healthy. However, greasy foods impair this balance by harming good bacteria. As a result, the number of bad bacteria increases (14). The imbalance of gut bacteria can contribute to obesity and chronic diseases. 


Depression is not just a feeling of sadness, it’s a mood disorder with physical and psychological symptoms that affect every aspect of your life. The exact cause of depression is unknown, but various factors could play a role including neurotransmitters, hormones, and inherited traits. Although millions of people have depression, this condition still requires further research. Evidence shows that depressive symptoms are strongly associated with the tendency to consume greasy foods (15). 

The link between the two isn’t exactly clear, but the role of nutrients stands out here as well. Just like the body, the brain also needs a wide range of nutrients to function properly. Consumption of greasy foods fails to deliver those nutrients which may contribute to depression. Also, greasy foods cause weight gain which is linked with negative body image and decreased confidence; both of which can only worsen your mental health.

Heart Disease and Stroke Risk

Greasy food is bad news for your heart and the entire cardiovascular system. Let’s start with the already established link between these foods and weight gain. Being overweight or obese puts you at a higher risk of heart disease and stroke. At the same time, an imbalance of gut microbiota can also put your heart health in jeopardy. 

Plus, fried foods that basically swim in oil and grease can raise blood pressure (16) and decrease levels of HDL (good) cholesterol, thereby making you more susceptible to heart disease and cardiovascular events such as heart attack and stroke. Additionally, greasy foods can contribute to diabetes (17) which can also aggravate heart health. 

Everyone’s favorite snack, potato chips, increases inflammation and may contribute to atherosclerosis (18). Atherosclerosis is a condition wherein plaque builds up inside blood vessels and it can lead to a heart attack or stroke. When talking about stroke, an observational study of 6000 people from 22 countries found that the consumption of fast food, including fried foods, increased the risk of stroke by 16% (19).

Type 2 Diabetes Risk

Type 2 diabetes is a lifelong condition that affects the way the body metabolizes sugar or blood glucose. Although prevalent, type 2 diabetes is preventable because its development has a lot to do with an unhealthy lifestyle. Of course, this also includes the food you eat. Greasy foods make you more susceptible to the development of type 2 diabetes (20). 

Why does that happen? Greasy foods are high in calories, contribute to weight gain, increase inflammation, and impair blood sugar control. The combination of all these factors leads to the development of type 2 diabetes. It’s also helpful to mention that weight gain linked with greasy foods also impairs insulin sensitivity. This may lead to insulin resistance and pave the way to metabolic disorders and eventually this lifelong condition. 


Acne is troublesome, not just for adolescents, but adults too. Although acne is usually connected with hormonal changes, lifestyle factors can influence these breakouts. Diet is one of those factors. This subject requires further research, but 51% of Americans attribute acne to greasy foods (21). The exact mechanism is unclear. However, greasy, unhealthy foods don’t deliver the nutrients your skin needs to function properly. Also, they contribute to weight gain. Being overweight or obese changes your hormones structure which may ultimately manifest itself through acne breakouts.

Let’s not forget that greasy food, and junk food in general for that matter, contain high levels of Omega-6 fatty acids, which increase inflammation that is also involved in acne formation.

Of course, further studies on this subject are important. 

Brain Function Problems

As mentioned above in this post, the brain needs a wide spectrum of nutrients to function properly. Unhealthy, greasy foods aren’t the best sources of vitamins and minerals. Negative effects of greasy food on the brain happen due to hypertension, weight gain, and metabolic syndrome; all of which develop due to an unhealthy diet. These factors harm the structure of the brain alongside brain tissues (22) and its activity. Consumption of fried and greasy foods can contribute to cognitive decline, decreased learning ability, increased inflammation, and impaired memory (23, 24).

Other Effects of Greasy Foods

Besides the above-mentioned effects of greasy and unhealthy foods, there are many other problems that may occur. Greasy foods can also contribute to:

  • Fatigue and daytime sleepiness
  • Increased risk of certain cancers 
  • Cravings for unhealthy foods
  • Difficulty losing weight
  • Stress and anxiety 

How to Avoid Greasy Foods

Eating greasy foods harms your health in more ways than one. But, it’s not just about fast food, it’s also about the way you cook at home. Using too much oil is never a good thing.

By avoiding greasy foods, you can improve your health and lower the risk of the health conditions mentioned above. The first step to making this happen is to opt for healthier cooking methods. Instead of deep-frying, you may want to try grilling, steaming, air-frying, or oven-frying your food.

Nowadays, there are many other ways for you to eat delicious food without too much hassle. To get inspiration, you can look for healthy food recipes online or experiment with different ingredients and cooking methods. 

Yet another important thing you can do is to replace greasy and unhealthy foods with healthier alternatives. Instead of fast food burgers, you can opt to make your own, which are far healthier. Also, instead of “regular” French fries, you can bake them in the oven. You can do the same with chips and other similar snacks. Healthier alternatives are even more delicious and they decrease the risk of the above-mentioned problems.


Greasy foods seem delicious and convenient. They take a few minutes to prepare or cost less than other foods. Their convenience and price make greasy foods a popular choice for many. However, these benefits come with a price – a higher risk of various health problems. In this post, we went through the most common problems associated with greasy food. You can lower the risk of diabetes, heart disease, and overweight or obesity by decreasing the intake of greasy foods. Experiment with different cooking methods and ingredients to discover all the beauty of a healthy diet.


  1. https://edition.cnn.com/2018/10/03/health/fast-food-consumption-cdc-study/index.html
  2. https://www.cdc.gov/nchs/products/databriefs/db360.htm
  3. https://fdc.nal.usda.gov/fdc-app.html#/food-details/170093/nutrients
  4. https://fdc.nal.usda.gov/fdc-app.html#/food-details/170698/nutrients
  5. https://pubmed.ncbi.nlm.nih.gov/29212483/
  6. https://pubmed.ncbi.nlm.nih.gov/17616781/
  7. https://pubmed.ncbi.nlm.nih.gov/21824755/
  8. https://pubmed.ncbi.nlm.nih.gov/10889789/
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1987329/#:~:text=Moreover%2C%20fast%20food%20consumption%20tends,vegetables%2C%20calcium%2C%20fiber).
  10. https://www.insider.com/processed-foods-could-speed-up-cell-aging-according-to-science-2020-9#:~:text=A%20diet%20high%20in%20ultra,that%20mark%20your%20biological%20age.
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5593462/
  12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6327730/
  13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5467063/
  14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4578152/
  15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3062726/
  16. https://pubmed.ncbi.nlm.nih.gov/14668269/
  17. https://academic.oup.com/ajcn/article/100/2/667/4576562
  18. https://academic.oup.com/ajcn/article/89/3/773/4596697
  19. https://pubmed.ncbi.nlm.nih.gov/20561675/
  20. https://pubmed.ncbi.nlm.nih.gov/28424256/
  21. https://www.yalescientific.org/2011/11/does-greasy-food-cause-acne/
  22. https://pubmed.ncbi.nlm.nih.gov/25919926/
  23. https://pubmed.ncbi.nlm.nih.gov/27752305/
  24. https://pubmed.ncbi.nlm.nih.gov/26874911/

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