Junk food diet makes you lazy


April 4, 2014
Brain & Behavior, Health

A new UCLA psychology study provides evidence that being overweight makes people tired and sedentary — not the other way around.

Life scientists led by UCLA’s Aaron Blaisdell placed 32 female rats on one of two diets for six months. The first, a standard rat’s diet, consisted of relatively unprocessed foods like ground corn and fish meal. The ingredients in the second were highly processed, of lower quality and included substantially more sugar — a proxy for a junk food diet.

After just three months, the researchers observed a significant difference in the amount of weight the rats had gained, with the 16 on the junk food diet having become noticeably fatter.

“One diet led to obesity, the other didn’t,” said Blaisdell, a professor of psychology in the UCLA College of Letters and Science and a member of UCLA’s Brain Research Institute.

The experiments the researchers performed, Blaisdell said, also suggest that fatigue may result from a junk food diet.

As part of the study, the rats were given a task in which they were required to press a lever to receive a food or water reward. The rats on the junk food diet demonstrated impaired performance, taking substantially longer breaks than the lean rats before returning to the task. In a 30-minute session, the overweight rats took breaks that were nearly twice as long as the lean ones.

The research is currently online and is scheduled for publication in the April 10 print edition of the journal Physiology and Behavior.

After six months, the rats’ diets were switched, and the overweight rats were given the more nutritious diet for nine days. This change, however, didn’t help reduce their weight or improve their lever responses.

The reverse was also true: Placing the lean rats on the junk food diet for nine days didn’t increase their weight noticeably or result in any reduction in their motivation on the lever task. These findings suggest that a pattern of consuming junk food, not just the occasional binge, is responsible for obesity and cognitive impairments, Blaisdell said.

“There’s no quick fix,” he noted.

What are the implications for humans? Do people who are overweight become less healthy or do less healthy people become overweight?

“Overweight people often get stigmatized as lazy and lacking discipline,” Blaisdell said. “We interpret our results as suggesting that the idea commonly portrayed in the media that people become fat because they are lazy is wrong. Our data suggest that diet-induced obesity is a cause, rather than an effect, of laziness. Either the highly processed diet causes fatigue or the diet causes obesity, which causes fatigue.”

Blaisdell believes the findings are very likely to apply to humans, whose physiological systems are similar to rats’. Junk food diets make humans — and rats — hungrier, he said.

In addition, the researchers found that the rats on the junk food diet grew large numbers of tumors throughout their bodies by the end of the study. Those on the more nutritious diet had fewer and small tumors that were not as widespread.

Blaisdell, 45, changed his diet more than five years ago to eat “what our human ancestors ate.” He avoids processed food, bread, pasta, grains and food with added sugar. He eats meats, seafood, eggs, vegetables and fruits, and he has seen dramatic improvements in his health, both physically and mentally.

“I’ve noticed a big improvement in my cognition,” he said. “I’m full of energy throughout the day, and my thoughts are clear and focused.”

An expert in animal cognition, Blaisdell conducts research that addresses the relationship between health and lifestyle (diet and exercise) and the relationship between a junk food diet and cognitive impairments it may induce.

“We are living in an environment with sedentary lifestyles, poor-quality diet and highly processed foods that is very different from the one we are adapted to through human evolution,” he said. “It is that difference that leads to many of the chronic diseases that we see today, such as obesity and diabetes.”




Junk food diet makes you lazy

16 Responses to Junk food diet makes you lazy

  1. 14391482 May 4, 2014 at 9:26 am #

    When thinking of food, humans should take into consideration the reason for food, in their day to day lives, in the first place. Are the foods we eat just based on supressing hunger pains, a growling stomach, or are they truly living up to their purpose of fuelling our bodies and the systems which allow our bodies to not just function, but to function at an optimum level, with longevity and disease prevention as side effects?
    An excess in junk food consumption and sugar consumption, which is closely related, not only causes the rate of obesity to rise rapidly having a direct influence on the diseases that are a result of obesity, but also influence the well-being of the person indulging. Inevitably, people that are overweight with unbalanced diets and a lack of exercise will feel lethargic, lazy and lack focus. Increased body mass results in an uncomfortable and unnatural amount of energy needed for normal bodily functions to occur and any exercise over and above that. The strain on the heart due to a large amount of body fat has a detrimental effect on ones bodily functions. Not only does junk food promote obesity, but there is a lack of valuable nutrients in these meals which is a fundamental problem when looking at the nutrients the body needs for muscle recovery, energy, focus, memory, improving eye sight, preventing diseases, promoting healthy skin, transporting nutrients around the body, building a strong immune system etc. These meals are filled with unbelievable amounts of unhealthy fats and carbohydrates that leave the body feeling overly full and lethargic. They do not sufficiently energize one’s body for a decent amount of time before causing inconsistent sugar level spikes/decreases, and that is why people are in fact “lazy” when continuously indulging in these meals.

    – Correction

  2. u14391482 May 4, 2014 at 9:06 am #

    When thinking of food, humans should take into consideration the reason for food, in their day to day lives, in the first place. Are the foods we eat just based on supressing hunger pains, a growling stomache, or are they truely living up to their purpose of fueling our bodies and the systems which allow our bodies to not just function, but to function at an optimum level, with longevity and disease prevention as side effects?

    An excess in junk food consumption and sugar consumption, which is closely related, not only causes the rate of obesity to rise rapidly having a direct influence on the diseases that are a result of obesity, but also influence the well being of the person indulging. Inevitably, people that are overweight with unbalanced diets and a lack of exercise will feel lethargic, lazy and lack focus. Increased body mass ressults in an uncomfortable and unatural ability for the body to provide sufficient energy for bodily functions and any exercise over and above that. The strain on the heart due to a large amount of body fat has a detrimental effect on ones bodily functions. Not only does junk food promote obesity, but there is a lack of valuable nutrients in these meals which is a fundamental problem when looking at the nutrients the body needs for muscle recovery, energy, focus, memory, improving eye sight, preventing diseases, promoting healthy skin, transporting nutrients around the body, building a strong immune system etc. These meals are filled with unbelievable amounts of unhealthy fats and carbohydrates that leave the body feeling overly full and lethargic. They do not sufficiently energize one’s body for a decent amount of time before causing incosistent sugar level spikes/decreases, and that is why people are in fact “lazy” when continuously indulging in these meals.

  3. nempheni s 14038308 May 4, 2014 at 4:24 am #

    I agree with the statement that says “Junk food makes u lazy” because you may find that processed food is easy and fast to prepare and also delicious and for people to leave something like that would be difficult so I think for one to look after their health they just have to find their motivation and decide how and what they want in order to stay healthy

  4. u14090024 May 4, 2014 at 3:03 am #

    This is a very interesting article and I agree with it one hundred percent. Junk food does have cognitive effects and also takes a toll on one’s metabolic functions and rates. That junk food may taste delicious but it doesn’t have all the nutrients needed to stay healthy because it is just filled with mostly fat and that could be why you may feel chronically fatigued too.

  5. Siobhan Marnewick (u14096422) May 2, 2014 at 10:27 pm #

    As they say your health is 70% diet and 30% exercise and good exercise can’t change a bad diet. The human body can’t survive on a junk food diet , because it has too much excess oil , fat and sugar which the body won’t be able to work through. Your body wants the healthy nutrients from healthy food , it’s good to have some junk food now and then just to give your body that shock , but not every day or every week.

    Living on a junk food diet will make you lazy , because your brain and body won’t be able to function on those bad sugars , fats and oil it might give you energy for 2 hours , but it won’t give you enough energy for the whole day. A good balanced diet is very important as it stimulates the brain giving it the necessary nutrients resulting in better concentration , a healthier body and better health , it also lowers your risk for obesity , high cholesterol , increased body mass , heart diseases , cancer , lack of energy etc.

  6. Obadiah, 14008247 May 1, 2014 at 6:10 am #

    The concept that junk food makes you lazy is one i definitely agree with. however on the other hand, as commented by u14244137,the trait of being lazy can also be an affect of genes and the environment.

    In this age, most of our food are not as fresh and healthy as in the past. Food is highly processed and although one might say; “I abstain from junk food” , the real question is what does the effect our normal day to day food diet have on us. In the past we may have been able to say with confidence “I abstain from junk food’ , but now due to our busy days, most of us pop into to grab a packet of chips or burger for lunch, which in essence can also be considered junk food. Although junk food may not play as major a role in causing fatigue in leaner people who exercise often, it still has an affect on our health.

  7. u14244137 May 1, 2014 at 1:40 am #

    Junk food can’t be seen as the only reason people are getting lazier either though, Yes it contributes greatly to a very lethargic and all around lazy feeling but even healthy foods can do that too if taken in excess. I agree that junk food can be seen as part of an all round balanced diet but only if taken in moderation. Another problem we need to start taking note of is what we classify as healthy food and as junk food, sometimes these lines get blurred by great marketing tools and fancy packagings.

    We all need to become more educated in what we are really putting in to our bodies and if we are to eat junk food we need to compensate for the added unneccassary calories elsewhere, whether it be by increasing exercise or decreasing the total amount of food we eat at later meals, I don’t believe we’ve gotten lazier to an extent that leads to the epidemic of increased weight gain we face today. Its a combination of things.

  8. 14120692 April 30, 2014 at 11:25 pm #

    Food plays an important role in one’s mood. In this article they refer to junk food being a cause for laziness. I agree with this notion, as junk food has many negative effects on our health. It is justifiable that a junk food diet makes one lazier, since it lacks all the necessary nutrients such as carbohydrates and proteins and thus does not strengthen one’s body through the increase in energy levels, thus leading to the deterioration in one’s health. Even though one feels highly satisfied and full when eating junk food, the lack of nutrients causes a lowering in the energy levels and impairs one to perform their activities for the day as efficiently as possible.

    An unhealthy diet, one filled with junk food, can lead to a variety of chronic diseases such as diabetes and obesity as mentioned above. This is because junk food is predominantly composed of sugar which when digesting, causes tension on one’s metabolism. It affects the organs involved in the control of glucose-levels in the blood, such as the pancreas, and thus could lead to diabetes. I agree with the previous comment by Mothuba (2014), obesity is caused by an excessive increase in body mass. Junk food increases the body mass, by converting the sugar that is digested into fat and thus it accumulates to increase the body mass. One becomes ‘lazy’ as the junk food intake increases. This leads to the decrease in energy levels and an increase in body mass and thus it becomes harder for one to move.

    People are becoming lazier due to more than just the increase of intake in junk food. It was mentioned in the article that when our ancestors were alive they ate much healthier and were more active; this is because technology was not as advanced as it is today. Technology also plays a vital role in the activity we carry out. Devices are being created that allows one to do tasks with little to no effort. The less one does, the lazier one becomes.

  9. Simone' 13250427 April 30, 2014 at 1:28 pm #

    Most of us know that junk food is unhealthy. It is calorie-dense and nutrient poor and almost all junk food is processed which is also not good. Although junk food make us gain weight it also causes health problems such as : high cholesterol, diabetes and heart diseases.Junk food make us tired and makes us less able to pay attention in class and tests. Most junk foods contain too much saturated fat, sodium or sugar. We should rather eliminate junk food from our diet and replace it with nutrient-dense foods that supply the vitamins and minerals we need for good health.

    A healthy body is a healthy life
    13250427

  10. Thulani(14301963) April 30, 2014 at 2:31 am #

    are there any good sides of junk food? ,because this article is biased on the bad sides of junk food.in the article it is said that the junk food has a lot of Carbohydrates and fats in them, and these are the essentials for the growth of all organisms. They contain a lot of sugar,and sugar is the main source of energy which gives you the go. i believe that with the right amount of junk taken, obesity and diabetes will be reduced and this junk will give people the stamina to do more things and not feel exhausted at all. In my opinion,rather than saying that junk food is unhealthy,it should be the person taking them who’s irresponsible and people should take a mix of these diet.Hence people do not need to stop eating what they love but to check the limit they are taking.

  11. HM Oosthuizen (14053952) April 29, 2014 at 6:40 am #

    Fast food and junk food is high in fat, sodium and sugar. Eating too much of this can lead to a range of health problems.

    Junk food contains large amounts of fat, which will cause you to gain weight- this can lead to serious health risks such as heart diseases, hypertension and high cholesterol, just to name a few.

    Junk food does not contain the correct amounts of protein, good carbohydrates and other nutrients that our bodies need. As a result of this, your blood sugar level will drop suddenly after eating junk food- leaving you feeling moody, tired and craving more sugar.

    Furthermore, added fats and oil are hard for the body to digest. As a result of this, bloodflow moves away from the arms and legs, straight to the gut to help with digestion, making you not want to move.

    Thus, junk food does not only cause health problems, it can also make you lazy.

  12. u14244137 April 26, 2014 at 10:48 am #

    The notion that a junk-food diet leads to a person being lazy is one that i agree with, to an extent. Food alone is not to blame for one’s level of activity. Laziness, like many traits, has a certain level of dependance on both genetics and environment. Everyone knows at least one person who seems to eat the same amount of junk food (if not more) but manages to stay super active and lean while everything seems to be a mission for them, who may bigger. This shows how your weight (much could be due to a hereditary predisposition) plays a role in sedentary levels.

    If something is more difficult for someone to do than it is for someone else, the person who finds it more difficult is more likely to take a break sooner or stop completely. So when the idea of physical labour (even if not that strenuous) retches up thoughts of difficulty the likely hood for that person to do that task isn’t as great as for the person who finds it easier. People can still be active and eat junk food diets they will just not necessarily be the healthiest.

  13. Annie u14228212 April 24, 2014 at 11:00 pm #

    There are many reasons why junk food is bad for us. I believe unhealthy foods can make you fat as well as decrease your motivation. The reason why junk food causes a person to be fatigue is because junk food often only make you full, but they do not have the essential nutrients to keep a person healthy. Causing a decrease in energy level. Junk food can lead to depression, because an unhealthy diet causes hormonal imbalances in a person, especially teenagers. This depression can cause the person to be unproductive. The high amount of refined sugar in junk foods are responsible for creating stress in a person’s metabolism. The sudden drop of blood sugar can make a person feel irritable and hence the reason why that person become “lazy” or don’t feel like doing any work. Junk food can also trigger memory impairment, slowing down a person’s learning ability which causes the person to feel demotivated. We must all try to eat healthier foods!

  14. Christiaan Schoeman April 13, 2014 at 1:36 am #

    Another interesting view of what food you eat and where your body gets the energy from is going back to the basics of cave men. Currently our bodies are used to getting energy from carbs and that is what most fast food consist of and that is all HI-GI. The idea of LO-GI is that the energy sources last a bit longer because the body takes time to break them down.

    The idea of eating like cave men is to cut out most carbs and therefore all processed foods like bread and pasta, and change your body to the original way of it getting energy from fat reserves. Fat is a better energy source than carbs in the sense that it takes a lot longer to break down and therefore your have energy for a longer time period which will sustain you to the next meal without even snacking in between.

    I know it feels so wrong to eat bacon and all those fatty foods, but that is exactly what we need for sustained energy.

  15. Michaela 14012384 April 5, 2014 at 12:40 pm #

    Most processed foods are not good for long lasting energy meaning that individuals who eat processed foods eat more and on a regular basis to get the required energy but this is not a sustainable lifestyle. Junk food is as processed as food gets so taking in large amounts is bound to lead to weight gain. Gaining weight means you need more energy, but most individuals who gain weight try to cut back on food resulting in tired people. Weight gains also lead to day-to-day task becoming a lot of effort thus leading to people being lazy.

  16. keorapetse motuba April 5, 2014 at 5:11 am #

    junk food is often high in carbohydrated which are nessesary sourseof of energy for the the body. bearing this in mind they are all so extreamy heavy and have a tendancy to build up and form layers of fat if unused this my acuse obesity and thus lack of energy due to increased body mass

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