Stress and Diet- Research by Shannon Connell
There is an interconnection between stress, cortisol levels, eating behavior, food choices, psychological and physiological health (Epel, Lapidus, McEwen, & Brownell, 2001). Stress can lead to either decreased or increased food intake (Adams & Epel, 2007). Today, most humans are increasing food intake as a reaction to stress (Adams & Epel, 2007). From an evolutionary perspective food supply was once unpredictable and often inconsistent (Pinel, 2009). Having the ability to eat large quantities of food and to store fat was at times critical to survival (Pinel, 2009). Industrialization has not only increased availability of food, but increased the variety of foods (Brannon & Feist, 2010). Serving sizes have increased and nutritional whole foods are less accessible and more expensive (Jung, 1997). Technological advancements are also leading people to more sedentary lifestyles and more stress, resulting in a major epidemic in chronic diseases, known as Syndrome X (Jung, 1997, Monat, Lazarus, & Reevy, 2007). Recent studies in psychoneuroimmunology and the allostasis of stress and eating suggest that increases in cortisol are related to greater food consumption and more unhealthy food choices (Epel, et al., 2001). Studies have also shown that dysfunctions of the hypothalamic pituitary adrenal (HPA) axis relate to food addiction and binge eating behavior (Adams & Epel, 2007).
All of life faces threats to homeostasis. Homeostasis is the body’s ability to maintain a stable physiological internal environment (Schneiderman, 2005). Stress is any sudden or intense disturbance, or disharmony of homeostasis balance (Lekander, 2002). Stress affects our entire being, nerves, cells, tissues, and systems of our bodies (McCall, 2007). Survival depends on our adaptability with stress. Stress if held, can disrupt nervous, endocrine, and immune system functioning resulting in “dis-ease” of body, mind and spirit (Lekander, 2002).
Psychoneuroimmunology (PNI) is a field of research that is interested in the interaction between the endocrine, immune and nervous systems, how these systems communicate in order to maintain health, and how they can become altered through stress and behaviors, such as eating and food choices (Glaser, 2005). Stress can be correlated with the increase in the hormone cortisol (Schneiderman, 2005). High levels of cortisol can be linked to psychological and physiological diseases (McCall, 2007). High cortisol levels are associated with increased fasting blood sugar, high systolic and diastolic blood pressure, increased triglyceride levels, and insulin resistance (Schneiderman, 2005), as well as increased risk behaviors such as disordered eating behaviors, poor quality food choices, cardiovascular disease, cancer and diabetes (Macht, Haupt, & Ellgring, 2004).
The ability to recover after stressful experiences and the perception of the stressful experience influences the total burden that stressors create on an individual (Monat, Lazarus, & Reevy, 2007). Stressors that are uncontrollable may become resistant to coping and behavior modification, resulting in continued elevation of stress hormones and chronic stress responses (Kiecolt-Glaser, 2002). This paper will discuss the relationship between chronic stress, obesity, disordered eating behavior, the psychoneuroimmunology of stress and diet, and cognitive-behavioral and mindfulness theories.
Today over 2/3 of adults and 1/3 of children are overweight or obese, it is predicted that by 2015 these numbers will increase (Wang & Beydoun, 2007). Since the 1970’s the increases in obesity has signaled a public health crisis, as the World Health Organization is classifying obesity as a disease (Wang & Beydoun, 2007). Obesity is the result of high-energy intake and low-energy expenditure (Pinel, 2009) and is associated with coronary heart disease, diabetes and cancer (Brannon & Feist, 2010). Metabolic Syndrome, or Syndrome X, is the combination of obesity, insulin resistance, oxidative stress, free radicals, inflammation, and hypertension (Roberts, Barnard, Sindhu, Jurczak, & Vaziri, 2006). Syndrome X is correlated with industrialism and globalization, in which diet is increasing in high fat and high sugar, processed foods (Roberts, et al., 2006). Much of the brain’s influence in the stress response is exerted through the hypothalamic pituitary adrenal axis (Black, 1994). The hypothalamic pituitary adrenal (HPA) axis is responsible for producing stress hormones (Schneiderman, 2005). It regulates growth, reproduction, thyroid function, sleep and appetite (Black, 1994). Cortisol and the (HPA) axis are both influential in stimulating eating during the stress response, increased caloric intake, and visceral fat development (Adam & Epel, 2007). Glucocorticoids are associated with the pleasurable effects of eating behaviors and possibly influential in the current food addiction epidemic of Western culture (Adam & Epel, 2007). Glucocorticoids are also associated with weight gain (Takeda, Terao, Nakaya, Miyamoto, & Rokutan, 2004), can disrupt metabolic functioning, and increase insulin resistance (Adam & Epel, 2007).
The industrial and agricultural revolutions have contributed to not only modern conveniences, but also to lower energy expenditure, increased food promotion and proportion, unethical food production, stress and food addiction (Marks, Murray, Evans, Willig, Woodall & Sykes, 2005). There are economic and political conflicts of interest that are reflected in the rising obesity population. The redefining and increases in weight charts over the last century (Brannon & Feist, 2010) is an example of the cover up attempts. The unethical practices of food production and its transportation and packaging are the major contributors to the environmental crisis we now face (Lappe, 2010). The solution is literally at the end of our forks! As the depletion of our soil, water, and air along with the production of low nutritionally content foods and their consumption are not only major contributors to environmental pollution but to the current chronic disease epidemic. A new way of eating and cultivating food can reduce global warming as much as 75% (Lappe, 2010).
Diet and nutrition are important aspects in brain functioning, biochemistry, and hormone regulation (Takeda, et al., 2004, Monat, Lazarus, & Reevy, 2007). Food is necessary for the body’s survival, and provides the systems of the body energy to sustain functioning and immune health (Takeda, et al., 2004). Studies have shown that stress and diet are interconnected. Macht, Haupt, & Ellgring (2005) conducted a study on the changes in eating behaviors of college students during examinations. Results showed that students who reported high emotional stress ate more to relieve stress and for distraction (Macht, Haupt, & Ellgring, 2005). This study has strong implications into the increasing of emotional eating as a stress response, and how eating behaviors are commonly changed with the experience of stress. The distraction hypothesis was explored in this study as many students reported to eat as a means to distract themselves from their stress prior to examinations (Macht, Haupt, & Ellgring, 2005).
In a laboratory study, women between the ages of 30 to 45, eating behaviors and food choices were observed after they were exposed to stressful testing (Epel, Lapidus, McEwen, & Brownell, 2001). Results showed that women with increased cortisol levels were more likely to eat larger quantities of food and choose more sweet and salty, high fat, low nutritional content foods (Epel, et al., 2001). This study is significant as it shows how increases in cortisol lead to increases in food intake and effects food choices.
Animal studies have been conducted that observe the link between stress and eating behaviors and health outcomes (Miller, Buehner, Chang, Harper, Sigler & Smith-Wheelock, 2005). Miller, et al. (2005) conducted an animal laboratory study with rats demonstrating that caloric restriction extended life span and slowed the aging process. The set point theory communicates that hunger and eating are triggered when the body needs more energy (Pinel, 2009). It is obvious with the increasing obesity epidemic that the set point theory is being over ridden. Just because a person may feel that they have a low level of energy does not mean that their body requires more food. With the rise of low nutritional content foods the body is still not getting the essential nutrients and amino acids necessary for proper and healthy functioning, therefore it triggers and alters the biochemistry of the brain, disrupts energy metabolism and produces more hunger signals (Pinel, 2009). The positive-incentive theory states that humans and animals demonstrate eating to have pleasurable results and often eat for pleasure rather than energy deficit (Pinel, 2009).
Dietary deficiency can increase susceptibility to the stress response, chronic stress and chronic disease (Monat, Lazarus, & Reevy, 2007). Dietary deficiency also alters food preferences, as we will develop the desire and taste for foods that will have (or we think will have) the nutrients we need (Takeda, et al., 2005). Unfortunately, with the unethical food production practices of Western culture, essential nutrients are being excluded and synthetic tastes and colors are being added to manipulate appetite (Lappe, 2010). For example in the meat industry, animal flesh is injected with color and plumping agents to create the illusion that the meat is healthy (Lappe, 2010). The animals in factory farms are living in terror and this increases their hormonal release of cortisol, which human consumers in turn eat and digest. The factory farm animals are injected with artificial hormones, forced to eat hormone laced food and even their peers! They are infested with cancer and disease, raped, murdered and then sold for human consumption. It is no wonder humans are experiencing increases in cancer, diabetes, heart disease, fear and anger.
The body’s health is dependent on enzyme balance (Pinel, 2009). When we eat dead foods, such as animal flesh, the body needs to use its existing enzymes to aid digestion. When we eat whole living foods, such as fruits and vegetables, we receive new enzymes, which increase our immune functioning and health. Unfortunately Western agricultural production is not environmentally or human health conscious. Most agriculture farms in the United States are increasing pesticide use, genetically modified foods, decreasing food variety, depleting our soils, polluting our water and air (Lappe, 2010). Human psychology and health is a multilayered construct. The environmental effects of our food production such as pollution, disconnection to nature, population increase and greed are interconnected and influential to the increasing levels of human stress, which is correlated and expressed in our current culture (Takeda, 2005).
Addiction is the inability to accept the present moment. It is an impulse to seek the next illusion or high, or to cover up or hide from the underlying root of behavior (Baer, 2003). The obesity epidemic is the resulting consequence of the Western culture’s addiction to food. The paradox is that we have become addicted to the very essence we need for survival. Our addiction to the pleasurable aspects of processed food has ultimately led to its capitalization, creating new products that are further and further away from the natural essence. The corporate greed and competitiveness to create new synthetic foods and products for sale while knowing the biopsychological effects should be illegal! Processed foods have the same biological responses in our bodies as most narcotic drugs and “activate the brain reward system” (Adam & Epel, 2007, p. 455). People have developed tolerances and cravings, experience binges and withdrawals from sugars, caffeine, fried salty and processed foods. Just like narcotics, processed foods interrupt the functioning of all systems of our bodies. Since processed foods can alter our hormones and even alter our serotonin levels (Takeda, et al., 2005), which are significant in depressive disorders, there should at least be surgeon general warning labels on processed food packaging. Public policy is needed as it is becoming clear that the current food production practices and cultural conditioning of our society plays a significant role in our current human and environmental health crisis (Lappe, 2010).
Mindfulness theory is the practice of increasing mindfulness and decreasing mindlessness (Langer & Moldoveanu, 2000). Mindfulness theory teaches acceptance for the ever-changing world (Langer & Molodoveanu, 2000), with the goal to increase cognitive flexibility, unconditional self-acceptance, and to decrease self evaluation, social comparison, and rigidity (Carson & Langer, 2006). Mindfulness interventions have proven successful in cognitive-behavioral change. Cognitive-behavioral change supports that through conscious self-study and awareness a person has the ability to cognitively choose to adapt their behavior according to the moment and according to their state of mind. When perception is coming from mindfulness a person can choose to see the positive value of the present, often stressful, situation and take it as an opportunity for growth and development (Monat, Lazarus, & Reevy, 2007). Perhaps the most important aspect of the mindfulness and cognitive theories is that the individual develops responsibility for their state of being, actions, decisions and perceptions. This self-awareness and integrity evolves into wisdom and creates the self confidence to become an active participant in health. Mindfulness theory creates a participatory science and through self-reflection and research comes social change.
In a study of a group of obese women suffering with binge eating disorder (BED) a 6-week mindfulness intervention resulted in reports of less binge eating behavior, greater self-awareness and greater self-acceptance (Kristeller, 1999). In another study of women with bulimia nervosa, mindfulness training resulted in less behavior extremes (Ludwig, 2008). These study results imply that mindfulness may be an effective treatment for disordered eating and addiction.
Enough evidence has been compiled to show the benefits of mindfulness and healthy eating and their effects on stress and coping. The practice of mindfulness with non-attachment can help people accept and be with discomfort. The current health care system all too often enables patients to mask or cover up symptoms, especially when it comes to lifestyle and diet, with a pill or a quick fix surgery. Mindfulness and cognitive-behavioral therapies will assist people in making conscious consumer and consumption decisions when it comes to eating and encourage individuals to take responsibility for their actions that affect their health, as personal effort towards health can inspire self-empowerment.
The topic of stress, diet and mindfulness and their interconnection is important for future growth, as we need to produce healthier food and have healthier food production practices that are not only good for humans but for the environment as well. As mentioned earlier from an evolutionary perspective it may have been important for human survival to overeat and store fat, however now with the increased availability of food and the addictive qualities of poor nutritional content foods, overeating and visceral fat storage, the American diet has become a contract with chronic disease. The more research to support the interconnection between stress, mood, eating, food and health the better opportunity we have to help cut away at one of the root problems to our current health and environmental crisis. Through mindfulness and cognitive interventions we can help to address and treat the all too common and unrecognized addiction to Westernized foods.
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