Why does junk food make you feel sick?

As per a study in India, 38% of people eat 1 to 3 times junk food per week. And the industry of junk food is increasing rapidly at the rate of 40% per year.

This junk food is full of calories, sugar, and fat, making us ill and sick. When we eat, it tastes good, which makes us eat more and more, but it is a slow poison that makes us sick.

Eating junk food just for five days impacts the body’s ability of their muscles to turn glucose into energy. Over the years, the inability of converting glucose to energy can lead to insulin resistance and diabetes 2.

There are many reasons why it makes us feel sick. So, let’s understand all the ways in detail.

Blood Sugar

Junk food breaks down quickly, causing a rapid rise in the blood sugar due to the refined carbohydrates, no fibre and sugar; this creates insulin surge resulting in the drop of blood sugar.

The sudden rise and fall make people feel lethargic. Until the time you are healthy, your body will take and manage such blood sugar spikes. But in a scenario where the body cannot manage, it might lead to weight gain, type 2 diabetes, and insulin resistance.

High sodium

We need sodium for the efficient movement of the muscles and balance the mineral and water we intake. On average, an individual requires 1500mg of salt, but it might change a bit depending on several factors. But junk food consists of high salt, making you consume more than required.

High sodium invites problems like:

  • Heart diseases
  • Stroke
  • High blood pressure
  • Impacts the bone density
  • Bloating the stomach helps your body retain fluid, which builds up extra fluid.
  • High blood pressure puts pressure on the kidneys to filter out the unwanted salt.
  • It may make you puffy. It may also swell your face, hands, feet, and ankles, known as oedema.
  • You might feel thirsty as it leads to dehydration. Drinking water can neutralize the body’s water from the cells to carry out the required functioning.
  • More sodium makes the body retain more water; hence, you might gain weight.
  • Too much salt consumption can disturb your sleep by causing you restlessness or by making you wake up multiple times throughout the night.
  • You might feel weak as water makes you flush cells to balance out the composition of salt in the blood.
  • It might lead to diarrhoea or stomach cramps. Drinking water might help you replenish the water loss making you feel better.
  • It might lead to enlarged heart muscles, headaches, kidney problems, kidney stones, heart failure, and stomach cancer in the long term.


As per AHA (American Heart Association), only 100-150 added sugar calories are considered okay, but the drinks we consume consist of added sugar, around 12 ounces(39grams), which is approx. 8-9 tablespoons (151calories approx). This added sugar can affect your body in multiple ways:

  • Sugar makes your body release a happy hormone (dopamine) which makes you crave it and makes it hard to resist the feeling.
  • Sugar takes control over your mood and gives you energy, but a sugar crash can lead to jitteriness and anxiousness later on.
  • Sugary drinks and food can harm your teeth enamel and lead to tooth decay if not taken care of properly.
  • Excess sugar increases the chances of rheumatoid arthritis.
  • Excess sugar makes your age skin faster as the sugar gets attached to the protein in your bloodstream, creating AGE’s (advanced glycation end-products), which impacts your skin’s collagen and elasticity, leading to your skin ageing faster.
  • A large amount of fructose/ fructose corn syrup in sugar might affect the liver. It might lead to problems like non-alcoholic fatty liver disease and non-alcoholic steatohepatitis.
  • The extra insulin impacts your arteries as it makes the wall inflamed, thicker and decreases their elasticity which puts pressure on the heart over time, leading to problems like heart failure, heart stroke and heart attacks. People who get 25% of their calories from added sugar have twice the risk of dying as those who get less than 10% of their calories.
  • Sugar impacts the chain events which are required for an erection. A high sugar level in the bloodstream can make men impotent as it impacts the circulatory system, which manages the blood flow in our body and blood flow should be good to get an erection.

Fat and weight gain

Consuming sweetened beverages, candies, or any other high sugar product contributes to increased weight and chronic health diseases like obesity, diabetes, etc.

Increased blood pressure and insulin resistance as well contribute to weight gain. Insulin (hormone) produced by the pancreas moves sugar from the blood to cells to be used as energy. Insulin also helps in storage and forming in which form to store fat or glycogen.

When a person suffers from insulin resistance, their body stops responding to insulin as earlier, leading to increased insulin and sugar levels. High blood pressure impairs cells function by promoting inflammation which further increases insulin resistance.

When your body becomes resistant to insulin, it remains responsive to hormones that help in fat storage, which causes increased fat storage leading to increased fat in the body.

Junk food is rich in sugar and refined carbohydrates but low in protein, making you feel full. Protein is the most fulling micronutrient; it slows down digestion while maintaining sugar levels and regulating hunger hormones.

The lack of protein and other micronutrients make you eat more and more, leading to weight gain.


Scientists have found that our food is linked to the mind and body more intimately than previously thought.

According to a study in Montreal, regular consumption of junk food can cause changes to your brain’s chemical activity, leading to the onset of depression.

“A pro-inflammatory diet can induce systemic inflammation, which might increase the chances of it, and a bad diet further heightens the risk of depression”, said Dr Camille Lassale.

Chronic inflammation can impact mental health by transporting pro-inflammatory molecules to your brain, affecting neurotransmitters (responsible for mood regulation), said Lassale, University of London.

The high composition of fat and sugar leads to inflammation, which impacts the gut and the whole body, known as Systemic Inflammation. Therefore, the impact of a bad diet is somewhat equivalent to smoking, pollution and obesity.

People who regularly eat more sugar and fast food are 51% more likely to develop depression than those who don’t.


According to a new study, fast food may prolong the time taken to become pregnant. On the other hand, fruits helped in speeding up the process.

Less consumption of fruits (1-3 times/month) increases the chances of fertility by 8-12%. As per research by the University of Adelaide, women who ate more fast food realized that fast food boosted their infertility by 8-16%.

If you’re below 35yrs and haven’t conceived after a year, you should probably consult a doctor. In comparison, the women above 35yrs should have a fertility evaluation and consider treatment if they fail even after 6months of unsuccessful trying.

Even male fertility is at risk. As per a recent study in George Washington University, people who consume junk food regularly have higher toxins called phthalates. Phthalates have been linked to male fertility and many endocrine disorders. 

Immunity (Long term effects)

Diets high in fast food and highly processed foods may increase inflammation, gut permeability, and imbalanced gut bacteria. All of them collectively can impact your immune system.

Phthalates can leach into fast food and get into our system. After getting in your body, they can increase the production of inflammatory protein, which might decrease your immunity and cause immune dysregulation.

Studies have shown that sudden, frequent spikes of sugar can suppress your immune system, making you more prone to get sick. You should have colourful veggies and fruits; they will help you improve your immunity and help your body stabilize and regulate its performance.

According to recent research at the University of Bonn, our immune system responds to junk food as it responds to bacterial infections. The study demonstrated that bad food makes the body’s defence aggressive in the long run despite if a person switches to a healthy diet.

Following edibles and beverages, if consumed in excess, have shown harmful effects on your immune system:

  • Soda
  • Alcoholic beverages
  • Processed foods
  • Refined Carbohydrates
  • Tobacco products (not a part of food group still compromise with your immunity)


Food allergies have increased by 200% in the last 20 years.

As per the research of the University of Naples Federico II, children of the age group 6-12years who had food allergies had a higher level of advanced glycation end products (AGEs) under their skin than those who had no allergies.

AGEs are great for flavour but not good for our health. But few researchers say that AGEs are not the only factor that leads to increased allergies; there might be many more factors that increase, which haven’t been found yet.

According to Dr Lakiea Wright, a physician in internal medicine and allergy and immunology at Brigham and Women’s Hospital in Boston and the medical director at Thermo Fisher Scientific following can be the potential factors:

  • Climate change: Climate change can make the crops immunogenic and provoke the immune system, leading to allergies.
  • Dietary patterns: One should reduce processed food intake and focus on healthy and leafy vegetables and fruits.
  • Genes and environment: It just doesn’t include genes but exposure to allergens, pollution, chemicals, etc.

Mental Health

As per research by the journal Nutritional Neuroscience, adults under the age of 30 eat a lot of fast food, resulting in increased perceived mental distress.

The relation between the brain and food stems from the gastrointestinal tract, also known as the second brain, is unique. The bacteria in the tract produce neurotransmitter that carries the message from the gut to the brain.

Good bacteria increase positive neurotransmitters ‘ production when you have good healthy food. On the other hand, consumption of junk food increases inflammation in the body that hampers the production of neurotransmitters.

When your tract has positive neurotransmitters, it sends signals to the brain, and it reflects in your emotions, and when the percentage is low, it makes you feel low.

Sugar particularly spikes in inflammation which feeds the bad bacteria in the tract.

Consuming healthy food makes you less prone to mood fluctuation and increases your ability to focus.


Probably there would be many more ways junk food affects us which haven’t been researched yet. Food is the fuel to our body, till the time the quality of fuel will not be good how can you expect the body to work well in the long run.