The term “fast food” generally refers to food that people intend to consume quickly, either on- or off-site. There is plenty of well-researched evidence demonstrating the various negative health effects of eating and overeating fast food, in both the short- and long-term.
Fast food is typically very poor in terms of nutrition. Fast food tends to contain various substances that are generally unhealthful. It is high in sugar, salt, and saturated or trans fats, as well as many processed preservatives and ingredients. It is also low in beneficial nutrients.
People are consuming an extra 650 calories every day, compared with what we were eating 50 years ago. That is the equivalent of a burger, fries and a soft drink.
Not all fast food is bad, and a person can make an informed choice by doing research to find out the nutritional content of particular fast food items. These are available on the websites of most major restaurants. However, even the more healthful fast food items are generally high in sugar, salt, saturated fats and trans fats.
Because fast food is typically high in sugar, salt, and saturated or trans fats, looking at the short-term effects of these nutrients can help determine what happens in the short-term when a person eats fast food.
Eating foods with more sugar as the first meal of the day could make a person feel hungrier at their next meal than if they ate a low-sugar meal. This is because sugary foods are worse at providing satiety, or a sense of fullness.
Also, high-carbohydrate foods increase the body’s demand for insulin, which also promotes more hunger within a shorter amount of time after the meal. The more hungry a person is before their next meal, the more likely they are to eat more calories than necessary.
Consuming high levels of salt could have an immediate impact on the proper functioning of a person’s blood vessels. Excess sodium intake also has links to fluid retention.
Fast food is also often very low in fresh fruit and vegetables, which makes it hard for people to reach their recommended daily intake of at least 5 servings.
It may also be hard for them to reach their ideal fiber intake, which is at least 25 grams per day. Fast food is highly palatable, meaning that it is very quickly broken down in the mouth, does not require much chewing, and activates the reward centers in the brain rapidly.
This combination trains the palate to prefer these highly processed, highly stimulating foods. This reduces someone’s desire for whole, fresh foods.
There is plenty of well-researched evidence showing that regularly eating fast food can harm a person’s health. This is because most fast food is high in sugar, salt, saturated fat and trans fats, processed ingredients, and calories, and low in antioxidants, fiber, and many other nutrients.
Many fast food meals are very low in fiber. A low-fiber diet is associated with a higher risk of digestive conditions such as constipation and diverticular disease, as well as reductions in healthy gut bacteria. Irreparable effects of eating fast food on a person’s health include obesity, insulin resistance, type 2 diabetes, and various cardiovascular conditions.
A Western diet can lead to higher inflammation, lower control of infection, higher cancer rates, and higher risk of allergic and autoinflammatory disease. A study in the journal Thorax establishes a link between fast food consumption in teenagers and children and an increase in asthma, rhinoconjunctivitis, and eczema.
A study in the journal Appetite also suggests that there is a causal link between a diet high in saturated fat and simple carbohydrates, typical of much fast food, and a lower capacity for memory and learning. This sort of diet may also raise the risk of Alzheimer’s disease and Parkinson’s disease.
A diet high in salt often increases a person’s blood pressure, which means that a person is more likely to have a heart attack, stroke, kidney disease, or heart disease. A diet high in trans fats raises the amount of low-density lipoprotein, or “bad,” cholesterol and lowers the amount of high-density lipoprotein, or “good,” cholesterol. This means that a person is more likely to develop heart disease.
Typical fast food contains a very high number of calories. If a person eats more calories than they are burning during each day, they will put on weight, which may lead to obesity.
Obesity increases a person’s risk of developing a range of serious health conditions. Another consequence of younger people regularly eating fast food is their uninentional lack of understanding of basic meal preparation, cooking, and healthful eating.
Over time, this perpetuates a dependence on fast food, and people may not learn how to prepare healthful, balanced food in the home. Consuming such meals can support a person’s long-term health throughout their lifespan.
Lower Academic Achievement
Fast food consumption, has a negative effect on student achievement. The amount of fast food children eat may also influence their academic growth. There has been much debate over the marketing of fast food to children, with many experts claiming it encourages unhealthy eating.
Children who consumed fast food four to six times a week or every day scored up to 20% lower on math, reading and science tests than those who did not eat any fast food.
Fast Food Shrinks Our Brains
It can get you high. The brain has a reward system that hardwires us to want to engage in behaviours that we find pleasurable – like eating tasty foods. When we eat fast foods the reward circuits within our brains activate and release the chemical dopamine.
Our brains can become overwhelmed by the pleasure from these rewarding foods and in response, the brain adapts and makes more receptors for dopamine. This means a greater amount of fast food is needed to get the same “kick”, making us eat more, in the same way that an addict develops a tolerance to drugs.
So, our brains are hardwired to seek out and want rewarding foods, making us crave and desire sweet and fatty foods.
It grabs our attention and make us impulsive. We rapidly learn that these fatty, sugary fast foods are delicious and our attention is drawn to them when we see them. To resist the temptation we need the major control centre in the brain – the prefrontal cortex.
This area doesn’t mature until our early 20’s, which is a reason why teenagers can sometimes act impulsively. Recent research has also shown that consuming lots of sugary drinks when you are young could alter brain development.
It can also inflame your brain. It is highly refined and contains very high levels of sugars and fats, more than many natural foods. In the same way as eating food you are allergic to can inflame your mouth; fast foods can cause a similar reaction in the brain.
This is called neuroinflammation, and it sets off a self-perpetuating series of events leading to more inflammation that can damage brain cells called neurons.
It shrinks the brain’s learning capabilities. The hippocampus is the memory centre of the brain and researchers have found that people who eat lots of fast food don’t perform as well as those who eat healthy diets in simple memory tests.
It reduces the generation of new neurons. The birth of new neurons, or neurogenesis, happens throughout life in the hippocampus. These new neurons have high levels of neuroplasticity, meaning they are very easily activated by environmental events and are essential for forming new memories.
Reductions in the population of young neurons have been related to mental health disorders including depression, which brings us back to the notion of self-perpetuating cycles – fast food can make us feel pleasure when we are sad, so we eat more, which makes us sadder.