Food Reward: a Dominant Factor in Obesity, Part IV

What is Food Reward?

After reading comments on my recent posts, I realized I need to do a better job of defining the term "food reward".  I'm going to take a moment to do that here.  Reward is a psychology term with a specific definition: "a process that reinforces behavior" (1).  Rewarding food is not the same thing as food that tastes good, although they often occur together. 

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Healthy Skeptic Podcast

Chris Kresser has just posted our recent interview/discussion on his blog The Healthy Skeptic.  You can listen to it on Chris's blog here.  The discussion mostly centered around body fat and food reward.  I also answered a few reader questions.  Here are some highlights:

• How does the food reward system work? Why did it evolve?
• Why do certain flavors we don’t initially like become appealing over time?
• How does industrially processed food affect the food reward system?
• What’s the most effective diet used to make rats obese in a research setting? What does this tell us about human diet and weight regulation?
• Do we know why highly rewarding food increases the set point in some people but not in others?
• How does the food reward theory explain the effectiveness of popular fat loss diets?
• Does the food reward theory tell us anything about why traditional cultures are generally lean?
• What does cooking temperature have to do with health?
• Reader question: How does one lose fat?
• Reader question: What do I (Stephan) eat?
• Reader question: Why do many people gain fat with age, especially postmenopausal women?

The podcast is a sneak preview of some of the things I'll be discussing in the near future.  Enjoy!

Fast Food, Weight Gain and Insulin Resistance

CarbSane just posted an interesting new study that fits in nicely with what we're discussing here.  It's part of the US Coronary Artery Risk Development in Young Adults (CARDIA) study, which is a long-term observational study that is publishing many interesting findings.  The new study is titled "Fast-food habits, weight gain, and insulin resistance (the CARDIA study): 15-year prospective analysis" (1).  The results speak for themselves, loud and clear (I've edited some numbers out of the quote for clarity):
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Food Reward: a Dominant Factor in Obesity, Part III

Low-Fat Diets

In 2000, the International Journal of Obesity published a nice review article of low-fat diet trials.  It included data from 16 controlled trials lasting from 2-12 months and enrolling 1,910 participants (1).  What sets this review apart is it only covered studies that did not include instructions to restrict calorie intake (ad libitum diets).  On average, low-fat dieters reduced their fat intake from 37.7 to 27.5 percent of calories.  Here's what they found:
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Clarifications About Carbohydrate and Insulin

My statements about carbohydrate and insulin in the previous post seem to have kicked up some dust!  Some people are even suggesting I've gone low-fat!  I'm going to take this opportunity to be more specific about my positions.

I do not think that post-meal insulin spikes contribute to obesity, and they may even oppose it. Elevated fasting insulin is a separate issue-- that's a marker of insulin resistance.  It's important not to confuse the two.  Does insulin resistance contribute to obesity?  I don't know, but it's hypothetically possible since insulin acts like leptin's kid brother in some ways.  As far as I can tell, starch per se and post-meal insulin spikes do not lead to insulin resistance.
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Stress Weaken Our Endurance

The research discusses the relationship of stress and the immune system known as the body's immune system is getting a lot done. Since the development of science of psychoneuroimmunology is a science that links the relationship between the science of psychology, neuroscience and immunology, the conditions associated with this has been more widely studied.

Psychoneuroimmunology emphasizes the proofs associated with the body's immune system and its relationship to stress that occurs in person. Mentioned, a lot of the impact of stress on the human body's immune system resulting in a person more susceptible to diseases associated with the body's immune system.
Some time ago, when the day of the second world congress of the International College of Psychosomatic Medicine in Seoul, South Korea, speaker Prof. Christopher Coe of the University of Wisconsin, the United States back on psychoneuroimmunology explains in his lecture entitled "All Roads Lead To psychoneuroimmunology"

In his lecture Prof. Coe said that is getting a lot of research and facts that illustrate the involvement of stress in influencing the human immune system. Some diseases are connecting it and emphasized during the lecture is on asthma and fibromyalgia.
Asthma we know as a disturbance of respiratory diseases involving inflammatory cells and immune system in the body. Incurable disease that is (can only be controlled) is strongly associated with the role of the immune system and stress that can trigger an attack.

Fibromyalgia itself is a disease that emphasizes fault conditions on the complaint of pain in various parts of the body and the atmosphere is uncomfortable feeling associated with this condition. Pain disorder is more widely available on these women have recently studied the effects associated with stress and the immune system.
Conditions related to the immune system in patients with fibromyalgia disorders associated with decreased levels of cells called Natural Killer (NK), and Interleukin Sitokon. These conditions are also found in patients with depression.

No wonder the symptoms of depression and anxiety also is one sign of the condition of fibromyalgia. Fibromyalgia itself is known once more to a collection of symptoms (syndrome) involving a variety of complaints. Syndrome conditions is also often overlap with other conditions such as somatoform disorders include (psychosomatic), pain disorder, depressive disorder and disruption of prolonged fatigue (chronic fatigue syndrome).

At the end of his lecture, Professor Coe says there are still many open fields of research in this field and will certainly still more and more knowledge to be gained by studying stress and its relationship to the human body's immune system.

Healthy Skeptic Podcast and Reader Questions

Chris Kresser, Danny Roddy and I just finished recording the podcast that will be released on May 24th.  It went really well, and we think you'll find it informative and maybe even practical!

Unfortunately, we only got around to answering three of the questions I had selected:

1. How does one lose fat?
2. What do I (Stephan) eat?
3. Why do many people gain fat with age, especially postmenopausal women?

I feel guilty about that, so I'm going to answer three more right now.

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Long-Term Stress Make Our Brain Shrink

Reputation of stress as a cause of guard cells in the body becomes sluggish security has long been known. However, the impact of stress to health does not stop there. Stress also causes the brain to shrink a long time.
There are many causes of stress, such as unhappy marriages, jobs less stressful, traumatic events, up to trivial issues such as congestion. If chronic stress is left then the impact is quite harmful to the brain.

When stressed the body releases chemicals. In the long run these chemicals will be toxic to brain tissue, it can even kill brain cells when chemicals called corticosteroids was abundant and long lasting.
Corticosteroids are actually required by the body to increase the speed of reaction to the threat or often called the fight or escape response (fight or flight), by suppressing the immune system and increase the amount of sugar in the blood circulation.

Hippocampus, a part of the brain responsible for memory formation, is the most vulnerable to stress. That's why experts consider stress is closely related to the occurrence of dementia.
The scientists found that smaller brain condition that when they did brain scans of patients suffering from post traumatic stress of 9 / 11 attacks. The smaller size of the hippocampus was almost equal to the size of the brains of elderly patients with dementia.

Even so, experts said the results of this study may be too early to conclude the effects of stress on the brain because the number of respondents is too small.
While some studies have found that war veterans suffering from post traumatic syndrome also suffer from a severe brain disorder.

The study also revealed that the stress experienced by middle age can increase the risk of Alzheimer's. They are often under stress and anxiety are also two times higher risk of suffering from dementia.

Administrative Note

My blog is being mercilessly ripped off by cheesy feed aggregators that are using my material for commercial gain, often without attribution.  I was able to ignore them when there were only one or two, and when they appeared far down the list on Google searches.  But at this point, there are 20+ rip-off sites that ride my coattails under questionable circumstances, and are getting decent Google rankings, so I've had enough.  I'm changing my feed settings so that I only partially syndicate my posts, and I'm adding a short plagiarism warning to each post.

What that means is that if you're using an RSS reader, you'll have to click through to my blog to read my material in full.  I apologize for the inconvenience, but I don't see any other solution.

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Antibiotics Is Not Super Drugs

Several studies have shown, tend to be excessive use of antibiotics and is commonly given to a disease or condition that does not require antibiotics.

Antibiotics are powerful drugs and has saved many lives. But the point is well known, antibiotics are not a cure for all kinds of diseases. Antibiotics can only cure the diseases caused by bacterial infection.
"Use antibiotics appropriately to prevent immune germs," ​​said Prof.. Prahasto Iwan, Professor of the University of Gajah Mada Farmakolgi in the workshop and briefing the media about drug prescribing patterns in Indonesia, especially antibiotics, Saturday (26 /3/2011) on campus University of Indonesia,  Depok,  West Java.

In society, antibiotics are often purchased without a prescription and explanation. Communities often purchased with a prescription antibiotic that had previously gained, taking antibiotics for coughs, fevers and colds.

Furthermore, Iwan explained that the inappropriate use of antibiotics could endanger public health. As a result of bacteria that can be generated is mutated so that it becomes resistant (immune) to antibiotics. Bacteria that are resistant or immune to these difficult attenuated by the usual antibiotics.

Iwan admitted, information about the antibiotic so far has not been evenly distributed to medical personnel. "The unavailability of adequate information about drugs that are neutral is also one big problem for medical practitioners. Meanwhile, the information conveyed directly by the pharmaceutical industry through his envoys is often misleading or misleading," he added.

Dr. Sharad Adhikary, representatives from WHO, confirmed, treatment of infections caused by antibiotic resistant bacteria that normally would be very expensive. This is because what is needed is an antibiotic that is more up to date with the possibility of drug side effects is greater, and longer duration of treatment.
According to Sharad, the problem of antibiotic resistance is not a new problem, but more and more alarming and dangerous. "We can go back to the era before antibiotics," he said.

Why the bacteria can become resistant to antibiotics? Every time someone taking antibiotics, the bacteria that are sensitive will be killed. But the resistant bacteria will continue to live, grow and reproduce.

The use of antibiotics over and over again and not appropriate is a major cause of increasing number of drug-resistant bacteria. So, for those of you who have a cough, flu and fever does not need to consume antibiotics. Because, often taking antibiotics will not make you more healthy, and will not make you better.

Why Does Our Works Make Us Stress?

If you feel unhappy with the work undertaken, you are not alone. At least a quarter of workers around the world feel their jobs have taken away the joy of living. Stress is accumulated over time turned into a depression that is not realized.

In a survey of 1,200 employees in the United States known to only 12 percent who felt optimistic about the job.

Experts say the main cause of the employee's depression is an unstable economy. "The pressure to succeed and achieve higher targets created the concept of avoiding mistakes than the pursuit of success, the report of a survey conducted by management consulting firm.

To understand why the work environment creates a negative mindset, consider the general situation that is often experienced in the workplace.

1. Too results-oriented

The workers feel happy when they are productive and can not feel bad if otherwise. But with such a high target current employees often feel unhappy. Although even the lure of corporate giving rewards to employees whose performance is good but it can not be a source of motivation.

Motivation of employees should be driven by internal satisfaction as a positive reward and social support. Many workers complained they are required to not make the slightest mistake, but rarely get the appreciation for the excellent work already done.

2. Motivated by fear

Difficult economic situation and lack of employment make many employees are afraid to make mistakes and motivated by the fear of being fired if performance is bad.

3. There is no satisfaction

When asked if that makes you stay at work even though salaries are given a small, mostly answering to develop career opportunities, challenging work and exciting, as well as opportunities to improve skills through appropriate training.

Ask Me a Question

On May 13th, I'll be recording a podcast with Chris Kresser of The Healthy Skeptic. Chris interviewed me about a year ago, and I thought it went well. Chris is a good host and asks interesting questions.

This time around, we're going to do things a bit differently. I'll start with a little overview of my current thoughts on obesity, then we'll answer reader questions. The show is going to be mostly about obesity and related matters, but I may answer a couple of questions that aren't related to obesity if they're especially interesting. There are two ways to leave questions: either in the comments section of this post, or the comments section of Chris's post. The show will air on May 24th.
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Food Reward: a Dominant Factor in Obesity, Part II

How to Make a Rat Obese

Rodents are an important model organism for the study of human obesity. To study obesity in rodents, you have to make them fat first. There are many ways to do this, from genetic mutations, to brain lesions, to various diets. However, the most rapid and effective way to make a normal (non-mutant, non-lesioned) rodent obese is the "cafeteria diet." The cafeteria diet first appeared in the medical literature in 1976 (1), and was quickly adopted by other investigators. Here's a description from a recent paper (2):

In this model, animals are allowed free access to standard chow and water while concurrently offered highly palatable, energy dense, unhealthy human foods ad libitum.

In other words, they're given an unlimited amount of human junk food in addition to their whole food-based "standard chow." In this particular paper, the junk foods included Froot Loops, Cocoa Puffs, peanut butter cookies, Reese's Pieces, Hostess Blueberry MiniMuffins, Cheez-its, nacho cheese Doritos, hot dogs, cheese, wedding cake, pork rinds, pepperoni slices and other industrial delicacies. Rats exposed to this food almost completely ignored their healthier, more nutritious and less palatable chow, instead gorging on junk food and rapidly attaining an obese state.

Investigators have known for decades that the cafeteria diet is a highly effective way of producing obesity in rodents, but what was interesting about this particular study from my perspective is that it compared the cafeteria diet to three other commonly used rodent diets: 1) standard, unpurified chow; 2) a purified/refined high-fat diet; 3) a purified/refined low-fat diet designed as a comparator for the high-fat diet. All three of these diets were given as homogeneous pellets, and the textures range from hard and fibrous (chow) to soft and oily like cookie dough (high-fat). The low-fat diet contains a lot of sugar, the high-fat diet contains a modest amount of sugar, and the chow diet contains virtually none. The particular high-fat diet in this paper (Research Diets D12451, 45% fat, which is high for a rat) is commonly used to produce obesity in rats, although it's not always very effective. The 60% fat version is more effective.

Consistent with previous findings, rats on every diet consumed the same number of calories over time... except the cafeteria diet-fed rats, which ate 30% more than any of the other groups. Rats on every diet gained fat compared to the unpurified chow group, but the cafeteria diet group gained much more than any of the others. There was no difference in fat gain between the purified high-fat and low-fat diets.

So in this paper, they compared two refined diets with vastly different carb:fat ratios and different sugar contents, and yet neither equaled the cafeteria diet in its ability to increase food intake and cause fat gain. The fat, starch and sugar content of the cafeteria diet was not able to fully explain its effect on fat gain. However, each diets' ability to cause fat gain correlated with its respective food reward qualities. Refined diets high in fat or sugar caused fat gain in rats relative to unpurified chow, but were surpassed by a diet containing a combination of fat, sugar, starch, salt, free glutamate (umami), interesting textures and pleasant and invariant aromas.

Although the cafeteria diet is the most effective at causing obesity in rodents, it's not commonly used because it's a lot more work than feeding pellets, and it introduces a lot of variability into experiments because each rat eats a different combination of foods.

How to Make an Obese Human Lean

In 1965, the Annals of the New York Academy of Sciences published a very unusual paper (3). Here is the stated goal of the investigators:

The study of food intake in man is fraught with difficulties which result from the enormously complex nature of human eating behavior. In man, in contrast to lower animals, the eating process involves an intricate mixture of physiologic, psychologic, cultural and esthetic considerations. People eat not only to assuage hunger, but because of the enjoyment of the meal ceremony, the pleasures of the palate and often to gratify unconscious needs that are hard to identify. Because of inherent difficulties in studying human food intake in the usual setting, we have attempted to develop a system that would minimize the variables involved and thereby improve the chances of obtaining more reliable and reproducible data.

Here's a photo of their "system":
It's a machine that dispenses bland liquid food through a straw, at the push of a button. They don't give any information on the composition of the liquid diet, beyond remarking that "carbohydrate supplied 50 per cent of the calories, protein 20 per cent and fat 30 per cent. the formula contained vitamins and minerals in amount adequate for daily maintenance."

Volunteers were given access to the machine and allowed to consume as much of the liquid diet as they wanted, but no other food. Since they were in a hospital setting, the investigators could be confident that the volunteers ate nothing else.

The first thing they report is what happened when they fed two lean people using the machine, for 16 or 9 days. Both of them maintained their typical calorie intake (~3,075 and ~4,430 kcal per day) and maintained a very stable weight during this period.

Next, the investigators did the same experiment using two "grossly obese" volunteers. Again, they were asked to "obtain food from the machine whenever hungry." Over the course of the first 18 days, the first (male) volunteer consumed a meager 275 calories per day. The second (female) volunteer consumed a ridiculously low 144 calories per day over the course of 12 days, losing 23 pounds. Without showing data, the investigators remarked that an additional three obese volunteers "showed a similar inhibition of calorie intake when fed by machine."

The first volunteer continued eating bland food from the machine for a total of 70 days, losing approximately 70 pounds. After that, he was sent home with the formula and instructed to drink 400 calories of it per day, which he did for an additional 185 days, after which his total weight loss was 200 lbs. The investigators remarked that "during all this time weight was steadily lost and the patient never complained of hunger or gastrointestinal discomfort." This is truly a starvation-level calorie intake, and to eat it continually for 255 days without hunger suggests that something rather interesting was happening in this man's body.

This machine-feeding regimen was nearly as close as one can get to a diet with no rewarding properties whatsoever. Although it contained carbohydrate and fat, it did not contain any flavor or texture to associate them with, and thus the reward value of the diet was minimized. As one would expect if food reward influences the body fat setpoint, lean volunteers maintained starting weight and a normal calorie intake, while their obese counterparts rapidly lost a massive amount of fat and reduced calorie intake dramatically without hunger. This suggests that obesity is not entirely due to a "broken" metabolism (although that may still contribute), but also at least in part to a heightened sensitivity to food reward in susceptible people. This also implies that obesity may not be a disorder, but rather a normal response to the prevailing dietary environment in affluent nations.

A second study by Dr. Michel Cabanac in 1976 confirmed that reducing food reward (by feeding bland food) lowers the fat mass setpoint in humans, using a clever method that I won't discuss for the sake of brevity (4). I learned about both of these studies through the writing of Dr. Seth Roberts, author of The Shangri-La Diet. I'd also like to thank Dr. Stephen Benoit, a researcher in the food reward field, for talking through these ideas with me to make sure I wasn't misinterpreting them.

I'd like to briefly remark that there's an anatomical basis for the idea of two-way communication between brain regions that determine reward and those that control body fatness. It's well known that the latter influence the former (think about your drive to obtain food after you've just eaten a big meal vs. after you've skipped a meal), but there are also connections from the former to the latter via a brain region called the lateral hypothalamus. The point is that it's anatomically plausible that food reward determines in part the amount of body fat a person carries.

Some people may be inclined to think "well, if food tastes bad, you eat less of it; so what!" Although that may be true to some extent, I don't think it can explain the fact that bland diets affect the calorie intake of lean and obese people differently. To me, that implies that highly rewarding food increases the body fat setpoint in susceptible people, and that food with few rewarding properties allows them to return to a lean state.

In the next few posts, I'll describe how food reward explains the effectiveness of many popular fat loss diets, I'll describe how this hypothesis fits in with the diets and health of non-industrial cultures, and I'll outline new dietary strategies for preventing and treating obesity and certain forms of metabolic dysfunction.

WHO Worried about Antibiotic Misuse

World Health Organization (WHO) warned, drug resistance is partly fueled by irrational use of antibiotics has killed hundreds of thousands of people every year. Therefore, the necessary treatment immediately to resolve the issue.

"We really see the evolution of rapidly increasing in the spread of this problem and the point is faster than solving the problem," said WHO's assistant director general Keiji Fukuda, Thursday (07/04/2011).

Health experts noted, few saj anegara who has a plan to handle the problem of drug resistance, which rose on increased consumption of antibiotics.

"In most countries, there is no plan, no budget, no line of accountability for this very serious problem. The surveillance system is weak, the system did not exist in many places," said Mario Raviglione, WHO officials who led the campaign against of tuberculosis. He added that the quality of antibiotics is questionable in some countries. "Optimal dose is not really a trigger mechanism that develop drug resistance. The use of antibiotics is often not feasible, we call it irrational. It allows the creation of resistance to drugs," he explained. In addition, the use of antibiotics in livestock - in order to promote growth and prevent disease and treat sick animals - also contributes to drug resistance. Any microbes that are resistant to the drugs develops in cattle can move on to humans through the food chain.

Because the microbes will always try to be resistant to the drugs, "this problem will never disappear," Fukuda said.

WHO expose the problem of antibiotic use as a major issue in memeringati World Health Day this year. WHO wants all governments, civil society and the pharmaceutical industry copes with a variety of strategies to deal with drug resistance.