DiSH Research in a Special Feature on Informing Policy Initiatives!

“Psychology has so much to offer policymakers, so I’m beyond excited to be part of this super exciting lineup designed to read like Memos to the President.” – Dr. T.

This week, Perspectives on Psychological Science published a special section on “Council of Psychological Science Advisors”. A selection of papers (including one from Dr. T & DiSH collaborators Dr. Andrew Ward and Dr. Traci Mann) that use psychological research to make policy suggestions are included in this special section of the journal. In the first article of the section, “Memos to the President From a ‘Council of Psychological Science Advisers'” (Teachman, Norton, & Spellman, 2015), authors explain that communication between researchers and policymakers is vital in order for psychological research to benefit humanity.

We couldn’t agree more, and Dr. T, Dr. Andrew Ward, and Dr. Traci Mann’s article “Promoting Public Health in the Context of the ‘Obesity Epidemic’: False Starts and Promising New Directions” (2015) clearly outlines some of the misconceptions about obesity that have prevented policy initiatives from being fully effective at promoting health. They also provide suggestions for how to better promote public health, such as making environmental changes that encourage people to engage in healthy behaviors. Read the full article here! 

Research that Changed Research: Anti-Fat Bias Among Obesity Specialists

In honor of the fact that Dr. T, Angela, and Laura traveled to  Atlanta last week to attend the Obesity Society’s Annual meeting at Obesity Week 2013, today’s article covers a study performed there over a decade ago.

Weight bias and discrimination has been found in many professional settings, especially with regards to employment, salary, and promotion decisions. However, the prevalence of weight bias among health professionals in medical care institutions is a growing concern.  If weight bias exists in health professionals, then is the increase in obesity-related health problems associated with the reluctance of obese patients to seek health care and poor treatment adherence and outcomes?

Back in 2000, Dr. Marlene B. Schwartz and Dr. Kelly Brownell and their colleagues administered the Implicit Associations Test (IAT) and a self-report questionnaire of explicit attitudes to 389 clinicians and researchers who were present at the international obesity conference in 2001. Research has confirmed that the IAT is a valid measure to predict prejudice behaviors towards a particular group.  This word classification task is a timed procedure where subjects are given a list of words and asked to sort them into a good or bad category. In this situation, the subjects were given words that corresponded to thin or fat people (See Figure 1 below). Participants then completed measures of explicit bias, indicating how positively or negatively they felt in general toward overweight and thin people respectively.

Figure 1

The results indicated that the obesity specialists in study exhibited a significant implicit anti-fat bias. The passage below is from the original article:

“Health professionals exhibited a significant pro thin, anti-fat implicit bias on the IAT. In addition, the subjects significantly endorsed the implicit stereotypes of lazy, stupid, and worthless using the IAT…Characteristics significantly predictive of lower levels of implicit anti-fat bias include being male, older, having positive emotional outlook on life, weighing more, having friends who are obese, and indicating an understanding of the experience of obesity.”

So what brought the DiSH Lab to Obesity Week? We wanted to find out whether how the prevalence has changed over the past ten years since the original iteration of this study using the exact same procedure among the same population of individuals. Is weight bias among obesity specialists increasing, or is this one domain where weight stigma may not be flourishing? Stay tuned for results of our 10-year follow-up study. 

Research that Changed Research: Is Food is the New Drug?

Since Halloween just past, I’m sure many of us are now struggling with an over-active (or re-instated) sweet tooth. But why is it that even not close to Halloween, when we have cravings, we usually prefer foods that are sugary, high in fat, and salty?

Davis and colleagues were wondering the same thing! But, they were more interested in why eating behaviors, namely overeating, produces addictive-like qualities in obese individuals. Coincidentally, sugary foods with high levels of fructose enhance physiological properties that are similar to those of addictive drugs. When large amounts of fructose are consumed, possible biological changes may actually promote overconsumption of food and cause problematic health issues.

In their study, Davis and colleagues recruited seventy-two obese participants between the ages of twenty-five and forty-six years old. Participants were measured in three areas: (1) clinical, (2) personality, and (3) eating behavior. Clinical measures include assessments on food addiction, binge eating disorder, depression severity, and ADHD symptoms. Personality measures include assessments on impulsivity, and addictive personality traits. Eating behavior measures include assessments on binge eating, hedonic eating, emotional eating and externally driven eating, food cravings, and snacking on sweets.  Participants were allowed to take the questionnaires home and return the package when completed.

The original passage below shows the results of the study:

“The powerful urges and cravings that compel drug seeking behaviours – often against the individual’s better judgement – are cardinal features of all addiction disorders (Garavan, 2010). As expected, the food addicts reported stronger food cravings than the non-FA group…we also expected, and found, that food addicts were more sensitive and responsive to the pleasurable properties of palatable foods as indicated by higher scores on a measure of the hedonic impact of food, and by more frequent snacking on sweets. Similar to the preliminary validation research by Gearhardt et al. (2009), we found that food addicts reported more overeating in response to emotional triggers like depression and anxiety, and were more likely to self-soothe with food compared to control participants…”

The results demonstrated a strong association between food and substance abuse within the group of participants involved in the study. This is strong evidence that maybe food addiction and drug addiction are two sides of these same coin. The study also suggests that there are different subtypes of obesity and that each may be vulnerable to distinctive threat factors in the environment, and a more personalized treatment approach might have better outcome for those who are struggling with obesity. The DiSH Lab couldn’t agree more with this last point! As our research has shown that diets fail more than they work, we are in full support of an approach to obesity that doesn’t blame a failed diet on the individual.

Research that Changed Research: Who will live longest: Underweight, Overweight, or Obese?

The prevalence of obesity and its association with health issues has been a growing concern in the United States. Many people are aware that obesity and overweight increases the risk of cardiovascular diseases and disabilities. However, is the hype about obesity distracting us from health outcomes at other BMI levels?

Katherine M. Flegal, Ph.D, and her colleagues looked further into the association of body weight and excess mortality through reports from the National Health and Nutrition Examination Survey (NHANES) conducted by the National Center for Health Statistics. By using baseline data from past surveys, researchers were able to estimate the deaths of U.S. individuals who are classified as underweight, overweight, and obese according to their Body Mass Index (BMI) levels. Body mass index was calculated as weight in kilograms divided by the square of height in meters. The BMI categories are as follows: underweight (BMI <18.5), overweight (BMI 25 to <30), and obesity (BMI ≥30).

The table below shows the risk of mortality at each BMI level broken down by age groups.

Screen Shot 2013-10-18 at 9.27.57 PM

Dr. Flegal found that underweight and obesity increase the likelihood of mortality compared to those with normal BMI levels. However, improvements in medical care and cardiovascular treatment has led to a decrease in morality rates of obese individuals. These results are consistent with the increase in life expectancy in the United States. The passage below is from the original article:

“We did not find overweight (BMI 25 to <30) to be associated with increased mortality in any of the 3 surveys. Our results are similar to those of a previous analysis of NHANES I and II data that found little effect of overweight on life expectancy… In many studies, a plot of the relative risk of mortality against BMI follows a U-shaped curve, with the minimum mortality close to a BMI of 25; mortality increases both as BMI increases above 25 and as BMI decreases below 25, which may explain why risks in the overweight category are not much different from those in the normal weight category.”

The results from this study demonstrates the importance of maintaining a healthy weight. It is also important to note that not only is there an increase in excess mortality for obesity,  but also for underweight. And the most ground-breaking part of this study is that it seems that the lowest mortality risk falls somewhere between overweight and OBESE! Dr. Flegal’s research findings have inspired the DiSH Lab to reconsider BMI as a reliable marker of someone’s health – according to this study, it just isn’t.

Research that Changed Research: General Adaptation Syndrome

When we face immediate danger, our bodies go through a physiological reaction to help us handle stress very quickly. This reaction is known as your “fight or flight” stress response. The stress response not only increases your heart rate and blood pressure, but also slows down digestion, growth, and reproduction while it numbs pain and suppresses the immune system. Evolutionarily, these adaptations were a good thing – they helped us run away from lions! However, the stressors we face nowadays are seldom the type that require a literal “fight or flight” (when is the last time a saber-tooth tiger was chasing after you?). Chronic stress more often comes in heavy workloads, time management, and money struggles, so what happens to our bodies when we have a physiological stress response to these types of stressors?

Hans Selye, M.D., Ph.D. (1907-1982) introduced the General Adaption Syndrome (G. A. S.) concept to explain the three stages of interrelated adaptive reactions to non-specific stress: the Alarm Reaction, the Stage of Resistance, and the Stage of Exhaustion. During the first stage, the body recognizes danger and the “fight or flight” response sets off by the activation of the HPA axis, the sympathetic nervous system, and the adrenal glands. The problem occurs when the energy provided by the main stress hormones cortisol, adrenaline, and noradrenaline are not used by physical activity and excess production of cortisol remains in the body. The body then shifts into the resistance stage, where homeostasis begins to restore balance and repair damages. Here, the problem occurs when chronic stress puts the body in a state of arousal with little or no recovery time. At the final stage, stress level remains high and the body’s adaptation energy supply is burnout, causing damaged nerve cells and adverse function of the autonomic nervous system. Selye’s theory was that stress is the major cause of disease because chronic stress causes long-term chemical imbalance in the body. The passage below is from the original article:

Why does exposure to the same stressor produce disease only in certain Individuals?

It is undoubtedly true that the same drug, microbe, emotional irritant, or physical injury may produce a disease of adaptation in one person and be tolerated with impunity by another. It should be recalled, however, that the general adaptation syndrome is a useful, normal physiological reaction to stress; only its derailments have been interpreted as diseases of adaptation. Hence exposure to a stressor can be expected to produce such diseases only if the defence reaction is inadequate. Thus, for instance, in our experimental efforts to produce the hyalinosis-hypertension syndrome in rats by exposure to cold we found it necessary to perform unilateral nephrectomies and to keep the animals on high sodium, high-protein diets. All these conditioning circumstances failed to produce disease in the absence of stress, but upon exposure to cold they caused a derailment of the general adaptation syndrome, with consequent cardiovascular lesions, nephrosclerosis, and a rise in blood pressure. It is very probable that ill man also, under the influence of stress, similar diseases would develop only when the general adaptation syndrome is prevented from evolving in a normal manner, as a result of adverse conditioning factors.

Ultimately, with high levels of stress, we also see increases in health problems and diseases. This is where the DiSH Lab comes in, as Selye’s G.A.S. model has inspired and guided our focus on chronic stressors such as dieting and weight stigma to understand the impact on physical health.

Research That Changed Research: Does Rejection Hurt?

“Sticks and stones may break my bones, but words will never hurt me.”

We learn from a young age that the phrase above is not completely true. Words do hurt, especially when others are teasing and calling you names. Perhaps, it is not what people say that really hurts you, but the feeling of being socially excluded. But really, social pain and physical pain are two entirely different experiences, right? Actually, the two are more closely related than you think. An fMRI study of social exclusion showed that regions of the brain typically associated with physical pain distress also play a role in the emotions associated with social rejection.

Dr. Naomi Eisenberger and her colleagues used a computerized ball-tossing game, called “Cyberball,” to stimulate the feeling of social exclusion and used functional neuroimaging to capture the brain regions involved. While undergoing fMRI, research participants were to play Cyberball, the virtual game of catch, with two other “participants,” actually simulations from the computer program. The first game allowed the participant a fair amount of ball exchanges with the computers, but the second game completely excluded the participant from the game. The passage below is from the original article:

“In summary, a pattern of activations very similar to those found in studies of physical pain emerged during social exclusion, providing evidence that the experience and regulation of social and physical pain share a common neuroanatomical basis. Activity in dorsal ACC, previously linked to the experience of pain distress, was associated with increased distress after social exclusion. Furthermore, activity in RVPFC, previously linked to the regulation of pain distress, was associated with diminished distress after social exclusion.”

Eisenberger’s social exclusion study taught us that social exclusion hurts, but it also helped us find ways to relieve social pain. If you are rejected by your peers, it could be a sign for you to change your ways or seek positive connection with friends and family. What other ways might help relieve social pain? Positive social interactions, healthy foods, and exercise! And this is where DiSH Lab comes in!

Research that Changed Research: Stress and Telomere Length

Take a look at the United States Presidents (See photos). From the start of their term to the end, their appearances change dramatically. This is a perfect demonstration of how in just 4 to 8 years, chronic stress contributes to years of aging on the skin, gray hairs, drooping eyes, wrinkles, and even balding spots. It is obvious that being the President of the United States is not an easy job. But, why does psychological stress cause premature aging and health issues? Researchers discovered three possible ways of cell aging: immune cell function or distribution, oxidative stress, or telomerase activity.

Dr. Elissa S. Epel and her research team hypothesized that stress gets “under the skin” through the modulation of the rate of cellular aging. Evidence showed that long-term stress is significantly associated with increased oxidative stress, reduction in telomerase activity, and shorten telomere length. Therefore, to test their hypothesis, 58 premenopausal mothers were examined and separated into two categories: the control mothers (biological mothers of a healthy child) or caregiving mothers (biological mothers of a chronically ill child). The intention of the study was to indicate the importance of perceived stress of each mother and measure the objective stress. The average length and activity of the telomeres were measured quantitatively in the peripheral blood mononuclear cells (PBMCs).

The following passage is from the original article:

“It is also notable that, in women, self-reported distress has been related to greater oxidative DNA damage (8-OH-dG) (12). Oxidative stress shortens telomeres in cells cultured in vitro (10). Our findings that perceived and chronic stress correlated with higher oxidative stress and shorter telomere length demonstrate this relationship cross-sectionally for the first time in vivo. Lastly, if the observed lowered telomerase activity represents chronic levels, it too could have contributed to the shortened telomeres in PBMCs.”

Dr. Epel’s research on the impact of psychological stress on telomere length opened the door to new interventions that may help lower perceived stress to help decrease the rate of telomere shortening. The prevention of telomere shortening is important in cell senescence and longevity, and therefore, helps to increase mortality rates and deterrence of diseases. Dr. Epel’s research findings reintroduce the importance of stress and its detrimental effects on health and guide DiSH lab’s own stress-related studies.

Research that Changed Research: The Minnesota Starvation Experiment

Have you ever been so hungry that you felt like you were starving? Even though you ate just a few hours ago, but it felt like it has been days since your last meal? And you probably experience the physical as well as psychological effects of hunger such as stomach cramps and grumpiness. Well, the Minnesota Starvation Experiment took hunger to a whole new level, but not without a good cause, of course!

In hopes to produce a dissertation on human starvation in laboratory stimulation of famine and to investigate different methods of treatment for famine victims at the end of World War II, the clinical study took twelve months to complete. With the participation of thirty-six white male volunteers between the ages of 22 to 33 years old, the study had four phases: Control Period (12 weeks), Semi-Starvation Period (24 weeks), Restricted Rehabilitation Period (12 weeks), and Unrestricted Rehabilitation Period (8 weeks). During the Semi-Starvation Period, the participants were given two meals a day that was adjusted to produce a total loss of about 25% over the course of 24 weeks. The participants were also assigned to perform physical tasks and were expected to walk 22 miles per week. Participants kept journals to record personal psychological effects of prolonged famine-like starvation.

The most striking effect of semi-starvation reported by the participants was not the physical discomfort, but the frustration of constantly thinking about food. The following is a passage from the Original Article:

“Food became an obsession for the participants. Robert Willoughby remembered the often complex processes the men developed for eating the little food that was provided: “. . . eating became a ritual . . . Some people diluted their food with water to make it seem like more. Others would put each little bite and hold it in their mouth a long time to savor it. So eating took a long time.” Carlyle Frederick was one of several men who collected cookbooks and recipes; he reported owning nearly 100 by the time the experiment was over.”

Dietary restriction is a big part of our focus in the DiSH lab, and the Minnesota Starvation Experiment showed the effects that dietary restriction has on attitudes and behaviors related to food and eating. Results from the experiment showed obsessive thoughts about food and eating, in which participants had difficulty concentrating on ‘normal’ things. Changes in eating behaviors such as licking of plates and poor table manners persisted after the experiment. In more severe cases, some of the participants had a hard time following their diets and experienced episodes of binge eating. On participant even mutilated his own hand. Results like these help the DiSH Lab examine the role that diet has on an individual and its influence on health.

Research that Changed Research: Restrained and Unrestrained Eating

We know that everyone has different eating habits. Some people eat very little to feel full while others eat a lot. And considering the spectrum of disordered eating, we know that some people eat less than or more than they should. However, is there something different about the eating behavior of people of different sizes, such as that of an overweight individuals? Herman and Mack’s classic experiment with milkshakes and ice cream provided a breakthrough response in their study “Restrained and Unrestrained Eating.”

In this study, 45 subjects were randomly assigned to three preload conditions: 0 milkshakes, 1 milkshakes, or 3 milkshakes. After the preload, subjects were give three 3-pint container of ice cream in chocolate, vanilla, and strawberry flavors. The subjects were simply told that the experiment was a “taste” test, and were given the instruction to rate each flavor. After the ratings were provided, subjects were welcomed to eat as much ice cream as they want until the ten minute time mark. A eating habit questionnaire was administered after the taste ratings.

Of course, the actually variable being measured is the amount of ice cream eaten after the preload. The data showed that those with high restraint consumed more ice cream after a preload while those with low restraint consumed decreasing amount of ice cream depending on the amount of preload. The following passage is from the original article:

“In any event, we may conclude that despite the weak correlation between restraint and percent overweight, it is the dimension of restraint that is the best predictor of behavior in the present (and presumably, analogous) circumstances. By extension, it seems reasonable to conclude, at least tentatively, that restraint rather than simply a large degree of overweight is the critical variable governing the eating behavior of obese individuals. Our small sample of obese subjects was not homogeneous with respect to restraint, and behavior varied accordingly. Presumably, those studies detecting obese/normal differences have “capitalized” on corresponding differences in restraint.”

Herman and Mack’s experiment demonstrated that restrained eaters eat excessively more only when they violated their diet. More importantly, this paradigm set the stage for future eating research, even Dr. T’s  study  “Consumption After a Diet Violation Disinhibition or Compensation?” where she tested whether or not restrained eaters are able to control their eating behavior outside of an artificial setting. Dr. T found that even after a diet violation, restrained eaters do not overeat in everyday life (Read more).

Research that Changed Research: Bottomless Soup Bowl

When do you stop eating? Most people would say that they’ll stop when they feel full. A classic experiment called the Bottomless Soup Bowl found that most people today are not very good at detecting when they feel full. Why is that? Well, people rely on different cues to help make certain judgments. With regards to food, people rely on visual cues of portion size to determine when they should stop eating. Ever heard of the phrase “Cleaning the plate?” As a result, people do not feel satiety until they see that their plate is cleared, even when food portion is increased. Wansink defined this behavior as mindless eating.

To test Wansink’s hypothesis that visual cues of portion size influence consumption, 54 participants (18 to 46 years of age) were recruited to either be in the re-refilling soup bowl condition or the control condition. The following passage is from the original article:

“Despite consuming 73% more, those participants eating from the self-refilling bowls did not believe themselves to have consumed any more soup than those in the control condition. Those eating from normal bowls believed they had eaten 32.3 calories fewer than they actually ate. In contrast, those eating from self-refilling bowls believed they had eaten 140.5 calories fewer than they actually ate.”

The size of food portion has been increasing for the past years (All-you-can-eat buffets, super-size McDonald combo meals, etc.), along with the country’s obesity rate. The Bottomless Soup Bowl experiment opened a link to how eating behaviors influence food intake and helped DiSH Lab further examine what small behavior changes can help people eat better and maintain a healthy weight.