Junk Foods Are Harmful For Health And They Cause Obesity

In the below-given video, Dr. Stephan Guyenet explains how obese conditions develop and become a menace. (It is worth watching the entire video… possibly twice or thrice, as you find time for it. After all, there is no greater wealth than your good health.)

Someone who is obese always tries to seek the reasons for their obesity.

Most of us usually blame the person’s food habits for the overweight….generally junk foods or fast foods.

The obese condition cannot be pinned down to a very specific reason, but among the many reasons, one of them, like the harmful effects of processed junk foods, could be the main cause.

Many factors lead to an individual’s obesity conditions of an individual… from food habits to hereditary factors.

Some become obese because of certain diseases over which they have no control.

But in general, obesity is caused by combinations of various factors specific to the particular individual.

It so happens that even the children of the same parents living under the same conditions show a difference in body weight.

Obesity is a condition where the body begins to store an excess amount of fat in the fat cells.

Normally the brain, with the help of leptin and insulin hormones, can maintain a healthy balance of fat in the body.

Modern health researchers say that the inability of the brain to regulate fat storage in the body makes a person obese.

One of the best obesity researchers of our time is Dr. Stephan Guyenet, who has made great efforts to explain the brain’s role in regulating the body’s energy balances.

To put it in a nutshell, two specific parts of the brain … the .hypothalamus and the “Reward Center”…. play a crucial role in deciding the obesity conditions of an individual.

Dr. Stephan Guyenet also explains in his video and blog that some foods are more conducive to promoting obesity conditions in an individual than natural foods, which are not.

Changing Food Habits And Obesity Issues Of World Population

In human history, obesity and diabetes were not major health issues before 70 or 80 years.

In the last 50 years, obesity has increased from 13 to 34% and severe obesity (BMI=40+) increased from 1 to 9%.

That is to say, before the 1970s, obesity issues were less than 13% of the world population. Among these, most obesity issues were in regions specific to North America and Europe.

The obesity epidemic has arrived at an astonishing speed. People in 1000s of years of evolutionary history lived without the flab… but in the last 50 years, waistlines have ballooned exponentially.

As per some estimations, over 69% of the American population is currently overweight.

During the last 20 years, there has also been a massive increase in Type2 Diabetes and Heart Ailments in conjunction with the increase in obesity health conditions.

The number one reason for this massive increase over the last few decades is attributed to the changes in the food habits and lifestyles of the people.

The diet of people in general mostly consists of high calories foods. The daily intake of calories increased by an average of 360 calories per day.

Let us look at changing the food habits of people at length to see how they have altered the health conditions of the people living today.

Homemade Healthy Foods Of The Past Are Replaced With High Calories Processed Foods

The hustle and bustle of modern life have left people with little time for preparing traditional homemade foods.

People have gotten used to the highly processed foods commercially made for convenience’s sake.

Common folk mostly eat energy-dense, highly palatable, refined foods and red meats that are cheaper per calorie. Most people do not care to buy vegetables, fruits, and fish (much more costlier), which are healthy foods with essential nutrients and low calories.

Over the past decades, there was a steady increase in the intake of high-calorie food (mostly junk foods) among the American population over the past decades as income levels of the people rose.


Simple and tasty home-cooked meals of the past are replaced with fast foods. The pizzas and burgers will be delivered to your doorsteps just a few minutes after a phone call or order is made online.

It is estimated that about 48% of Americans do not prepare regular meals at home; they prefer to have ready-to-eat processed foods or meals at restaurants.

Soda and sweetened beverages consumption among most children and adults have become regular at an all-time high. They are drinking a lot of unhealthy empty calories daily.

The quickly spreading obesity epidemic among American children mostly contributes to the increasing consumption of beverages and processed and packaged foods.

Junk Foods Alters The Functions Of the Hypothalamus And Reward Centers In The Brain

Everyone will agree that the human brain is an unfathomable complexity hard to understand.

The main part of the brain is the cerebral cortex, where all higher-level functions of the brain take place, including reasoning, calculation, and creativity.

The other parts of the brain are mostly utilized for taking care of the various functions in the body; hundreds of functions, from the heartbeat to the slightest movement in the tip of a finger, are done on auto-pilot.

The hypothalamus is the specific part of the brain that controls the energy level balance in the body in unison with hormones like Leptin, insulin, etc.

The “reward center” in the brain is also at the hypothalamus. The ‘reward center’ regulates pleasures derived from tasty food, laughter, sensory pleasures, etc.

It would have been easy for us to manage our body weight by willingly denying unhealthy foods with the help of reasoning and the logical powers of the brain. Unfortunately, the brain cortex cannot control our eating habits, appetite, and satiation.

However, other parts of the brain pressurize us to make the right decisions based on our previous knowledge of what is good for the body.

Junk foods gradually alter the natural functioning of the brain centers that regulate appetite, satiation, energy level maintenance, etc.

The reward centers (aka Pleasure Centers) in the brain upgrade the rewards for junk foods….which creates an insatiable liking for the palatable taste of those foods and a strong psychological drive to eat more and more of them.

Brain centers easily develop and maintain a strong food addiction tendency towards junk foods. This makes junk foods to be a major reason for abetting obesity.

Junk Foods Promote Weight Gain In Several Ways

Health Risks Of Junk Foods

As we have seen in the above paragraphs, the hypothalamus regulates the body’s food requirements. This part of the brain is consistent and tries to ensure the energy balance is maintained in the body.

The hypothalamus can access the body’s fat storage levels (energy) from the signals sent by the leptin hormone and produces feelings of appetite and satiation accordingly.

The production of the leptin hormone increases with more body fat in the body…it indicates to the brain that the body has sufficient long-term energy storage already in stock.

When you have not taken sufficient foods, the fat storage level gradually decreases, and a lesser amount of leptin hormone is produced accordingly. The brain sees this situation as a shortage of energy deposits and quickly makes us feel hungry.

The leptin hormone level also can drop quickly when the body burns a lot of stored fat to produce energy. At the same time, we engage in energetic physical activities like jogging, running or any physical work.

The sudden drop in energy levels makes us feel tired and hungry…it’s an instant reaction by the hypothalamus in the brain.

In the case of an increase in energy storage, a higher amount of Leptin is released as a number as all fat cells are full of fat….the hypothalamus reacts to it by suppressing appetite and increasing the level of calories burned as well.[16]

When these coordinated functions between the brain and the leptin hormone are normal and healthy, a person neither starves nor becomes overweight due to excess fat storage.

Overweight issues happen when the brain gradually fails to detect the leptin levels in the blood. This particular health issue is called ‘leptin resistance,’ one of the main causes of obesity.

The fat cells in the body might be filled with a lot of fat storage… but the brain thinks it is empty because of leptin resistance.

It is good to understand the reasons that cause leptin resistance, as it is the main culprit for obesity.

Suppose you have already watched the video at the beginning of this article. In that case, you can see Dr. Guyenet mentions one of the reasons for leptin resistance is inflammation in the brain.

He explains this from the results of his trial studies conducted on rats; the eating of high calories foods gave rise to inflammatory cells in the brains of the rats.

According to the study results, the inflammation in the brain cells of the rats increased when fatty foods were served to the rats for seven consecutive days.

This same kind of cell inflammation also can gradually creep into the human brain cells in the hypothalamus when regularly consuming extremely high calories junk foods and processed foods.

The inflammatory brain cells lose the ability to sense the leptin release level in the blood; this leads to overeating and further aggravation of obesity.

Dr. Guyenet also tried to feed the rats with inflammatory brains cell with non-fatty foods…. gradually reversing inflammatory effects.

The mice fed on healthy diets showed no signs of brain cell inflammation.

This study also indicates the possibility of reversal of brain cell inflammation in human beings. It is possible to correct leptin resistance by adopting strictly healthy food habits.

Most obese people cannot shed weight and get back to normalcy as they are incorrigibly addicted to certain foods… especially junk foods and fast foods that have many harmful health effects.

Studies have exposed the bad effects of junk foods on the health of the body and brain. The inflammatory brain cells in the hypothalamus result from the regular consumption of high calories in processed food. This brain cell inflammation results in leptin resistance and increased possibility of stroke.

Junk Food Influences The Reward Centers In The Brain In Developing Food Addiction

We tend to obtain higher pleasures of taste when we eat our favorite foods. These foods positively stimulate dopamine (a neurotransmitter substance) in the ‘reward centers’ of the brain…higher rewards are assigned to such foods.

Junk foods receive higher rewards of pleasure at the ‘reward centers’ of the brain. This makes the person addicted to processed junk foods that derive higher pleasure.

This same principle applies to all substance abusers and alcohol addicts.

Any food that gives higher stimulation for dopamine release is considered good behavior in the ‘reward centers’ of the brain. This natural system developed is to gain better satisfaction from certain foods we eat and ensure our survival in the natural environment.

The problem with packaged foods is that they have selective ingredients that induce increased dopamine release.

It is also found that most processed junk foods have additives that influence the same area of the brain as in the case of drug abusers.

Children can get very fast addicted to junk foods because their brain is more susceptible to addictive substances.

The extraordinarily high rewarding characteristics of junk foods quickly influence the brain to accept them as the ‘good behavior’ that gives greater pleasure.

Some studies say that even the excessive craving for food in thoughts can make people eat more every time and get fatter…even though they are not addicted to any particular food.

Various study results on this subject, which are actually done to help people to lose weight, are exploited by the food manufacturing companies to add the right ingredients that will derive more pleasure from the processed food they make and sell.

Final Thought

Dr.Guyenet has given detailed information on why people get addicted to junk foods and how they affect our health in many ways.

He successfully establishes the roles played by our brain in developing obesity conditions.

First, junk foods cause inflammation in the brain cells, eventually leading to leptin resistance.

Secondly, junk foods have chemically manipulated ingredients that influence the reward centers in the brain to reward them with higher pleasures. They also work like addictive substances to make us addicted to those foods.

The healthiest food for anyone is the natural foods used by our forefathers for centuries. They are low in calories, healthy, and nutritious with no side effects like junk foods.

Natural foods hardly develop inflammation in the brain cells, and they do not alter the natural functioning of the reward centers in the brain.