The true causes of obesity are complex and varied.
There is no single solution, because ... factors [1] , both for external internally (our biology) and (environmental).
Not only that, but the combination of factors vary considerably between individuals. What are the causes of obesity in one person may have no effect on the other.
Modern research is increasingly focusing obesity Once the brain plays a role in how our energy (fat) are regulated.
In the video [2] above, Dr. Stephan Guyenet an obesity researcher and one of my absolute favorite bloggers [3] explains how the brain is to regulate energy balance and ... Why is not currently working.
He makes a convincing argument for the brain, especially places of "reward" and a portion of the hypothalamus, are among the main actors of obesity.
If you are interested in nutrition, health and the causes of excess weight, then I suggest you watch this video.
This is to understand an essential part of the puzzle of why certain foods but not others, make people fat.
Caloric intake is increased over the last decades
The numbers are staggering ... 1960-2009, increased obesity from 13 to 34% and extreme obesity (BMI> 40) was increased 1-9%.
Although obesity has slowly sliding along the 20th century, it began in 1980, rising.
This was a massive increase in type 2 diabetes, who often travels to obesity associated.
There are many different theories as to what is the cause of the obesity epidemic, but an inescapable fact that the calorie intake drastically simultaneously (increased 1 ).
In the graph, the blue line the rise in obesity, while the green line shows the increase in caloric intake.
The increase amounts to about 363 calories per day [4] . Sources vary on the exact numbers, but almost everyone agrees that there is a significant increase.
Conclusion: Obesity has increased in recent decades, almost perfect correlation with increased caloric intake in the population.
Increase the calories from packaged, processed foods (and drinks) come
Of course, we are not only to eat more ... eat more foods are processed, commercially prepared foods.
A century ago, ate a simple, home-cooked meals. Today, a large percentage of the food intake of these people is only fast food:
Note that this figure underestimates the true effect, because much of what people eat at home processed foods these days.
Studies have also shown that sugar [5] -sweetened increased beverage consumption, which accounts for about half of the calories increase in population ( 2 ).
The truth is that to go along the western processed foods, soon followed by obesity.
Conclusion: The processed increased caloric intake in recent decades due to an increase and packaged foods and sugary drinks is.
Junk foods affect the brain centers, how much we regulate eating
The human brain is the most complex object in the universe, gram for gram.
Most of it is the outermost layer, the so-called cortex [6] .
This is where most of our "advanced" functions ... performed, such as logic, creativity, language, mathematics, etc.
However, the logic part of the brain is not always in control.
There are other areas of the brain which are responsible for physiological functions such as breathing, heart rate, body temperature, and others.
These physiological functions are controlled subconsciously ... we have to think of it, because everything is on autopilot.
It turns out that the weight of the body is largely dependent on the brain (control 3 ). This is a region of the brain called the hypothalamus [7] , which regulates a variety of hormones and internal functions.
There is also a system called the reward system is activated when we do things that make us happy, such as laughing or eating.
Unfortunately, the cortex of the brain supports (logic and reason) do not really have full control of food intake, which is strongly influenced by other areas of the "primitive" brain.
The cerebral cortex can try ... but there are other parts of the brain is constantly trying to influence to put pressure on us to the steps that we have already decided they are not to be taken in our best interest.
As it turns out, has a direct impact on junk food, some of these brain centers that control and regulate appetite, hunger and body fat.
When the brains of people who tend to gain weight are affected in this way to eat a strong urge to create more physiological (and less burn).
The strength of the cognitive restraint ("Will") is nothing in comparison.
This is one of the main reasons why junk food, but do not collect "real" food ... obesity and perhaps other diseases.
Conclusion: For people who can eat to gain weight, junk food high physiological pressures of the brain to eat more and tend to gain weight.
Junk food can cause causes inflammation in the brain that leptin resistance
The main area in the brain that regulates energy balance is called the hypothalamus.
Detects various signals, including hormones, then we feel either full or hungry.
The brain regulates food intake, both short-term (one meal) and based on a long term basis ( 4 ).
The main hormone involved in the energy balance in the long term called leptin [8] , of the fat cells in the body (produced 5 ).
Fat cells produce more leptin ... and functions as a signal to the brain that we have saved a lot of energy and does not need to eat.
When we lose weight, the fat cells get smaller and start to make less leptin. This is interpreted by the brain as hunger, if we become hungry and start to burn fewer calories.
Conversely, if we gain excess fat, then the fat cells secrete more leptin, which recognize our brain that makes us have to eat, so that you feel full and calories at a normal pace to burn.
So the brain "defends" its fat mass and intended to prevent starvation or becoming fat, both to survive a negative impact on our ability in nature.
The problem is this ... very sophisticated system that is along the development of the control energy balance has been designed broken because the brain does not recognize the signal leptin.
This is called leptin resistance and is one of the causes of obesity.
If the brain does not "see" leptin from fat cells, which do not see, the fat cells are full of fat. In other words, the brain thinks that we are hungry, even if we have saved a lot of fat.
But if leptin resistance is one of the main factors for overweight, then what motivated the resistance to leptin?
According to Dr. Guyenet can inflammation in the hypothalamus, what is causing the brain to become resistant to leptin.
His laboratory was fed to rats, where a standard diet (rat), were fed with a fattening diet for 7 days mice mice studied in comparison. The results were astounding:
The green and red colors are bright spots that focus on inflammatory cells in the brain. As you can see, the number, size and activity increases dramatically eating diet for only 7 days.
But it goes beyond that ... some rodents also showed that there is probably also a low-level inflammation in the brains of obese people (occurring 6 ).
Also, studies show that rodents have no inflammatory reaction not leptin resistant, gives further support for this hypothesis has become.
Interestingly, this is not in a normal diet fed mice the case when the mice ... and a finishing diet were switching to a healthy diet, these changes can be entirely reversible.
This shows that the process is reversible, even if you follow a healthy diet in humans, based on real food.
But this leads to another problem ... actually to avoid the administrative or eat less unhealthy foods in the modern environment, foods become addictive.
Conclusion: The consumption of highly processed junk food can cause inflammation in the brain's hypothalamus, which leptin resistance. This makes the brain thinks the body is starving.
Junk food is very rewarding, it can cause addiction in some people
Another problem with junk food is that they are very rewarding. They give us joy.
What we perceive as pleasure is actually a flood of dopamine [9] in the reward system of the brain.
This acts as a signal to the brain that is good this behavior, and the brain is wired to behaviors that find stimulate the release of dopamine.
While this system has worked in the area of natural food, modern junk food as "super stimulated." They cause intense dopamine release, similar to drug abuse, such as cocaine work.
In fact, numerous studies have shown that processed junk activate the same brain areas such as substance abuse ( 7 , 8 ).
For people who are sensitive, can lead to outright addiction [10] , where people completely lose control over their consumption.
Studies show that junk food, several symptoms that are almost exactly the same as the symptoms of addiction (lead are 9 , 10 , 11 ).
In other words, the rewarding effects of junk food hyper "deviation" of the pathways in the brain that are designed to help us look for behaviors that we bring joy and are good for our survival.
But even people who do not "hooked" on junk food, many experience various addictions like symptoms [11] , such as anxiety and obsessive thoughts about food, the increased supply leads to energy gain and fat ( 12 ).
Food companies are aware that everything ... and with all sorts of tricks [12] for food as his "reward" as possible.
Home message
If you want to dive into the science behind it, then Dr. Guyenet [13] wrote a detailed seven-part series on her blog ( Part I [14] , II , III [15] , IV , V , VI , VII [16] ).
I recommend you to read it.
Although the causes of obesity are complex and varied, the evidence clearly points to problems in the brain are among the main causes.
The best thing you can do for yourself, is a diet that live on the true food and a healthy life [17] , which is not suitable for low-grade inflammation.
Avoid processed foods [18] with high sugar, refined grains, vegetable oils [19] and trans-fatty acids [20] , and replace them with real food is a good place to start.
Bad food makes you fat and sick ... but the only whole food ingredient is the key to good health. Period.
Credentials
- ^ several factors (authoritynutrition.com)
- ^ Video (www.youtube.com)
- ^ Blogger (wholehealthsource.blogspot.com)
- ^ calories per day (authoritynutrition.com)
- ^ sugar (authoritynutrition.com)
- ^ cortex (en.wikipedia.org)
- ^ hypothalamus (en.wikipedia.org)
- ^ leptin (en.wikipedia.org)
- ^ dopamine (en.wikipedia.org)
- ^ downright addictive (authoritynutrition.com)
- ^ symptoms (authoritynutrition.com)
- ^ all sorts of things (authoritynutrition.com)
- ^ Dr. Guyenet (twitter.com)
- ^ Part I (wholehealthsource.blogspot.com)
- ^ III (wholehealthsource.blogspot.com)
- ^ VII (wholehealthsource.blogspot.com)
- ^ healthy lifestyle (authoritynutrition.com)
- ^ processed foods (authoritynutrition.com)
- ^ vegetable oils (authoritynutrition.com)
- ^ Trans fats (authoritynutrition.com)
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