Methodology for studying high-fat diet effects on anxiety and energy

¶ … High-Fat, High Calorie Diet on Depression, Anxiety and Energy Levels

The methodology of a study is particularly important, because those who read the study must be able to understand what the researcher did, and those who want to replicate the study need to be able to do so without becoming confused about the researcher's goals, ideas, and beliefs. Discussed here will be information about the sample, the variables, the analysis, and the procedures used, so as to clarify any concerns that might otherwise be seen.

Subjects will be recruited through public advertising for volunteers to participate in an 8-week study regarding diet, panic, anxiety, and energy levels. They will be screened to include only non-depressed women between the ages of 18 and 28 years of age with a BMI between 18.5 and 24.9. No more than 25 subjects will be recruited due to time, space, and budget constraints. Recruiting only non-depressed women between 18 and 28 years of age will be done for two reasons - to start the study with a baseline of healthy subjects in a specific weight range, and because depression and anxiety are both much more common (or at least much more highly reported) in women than they are in men (Hudson, 2000). None of the subjects will have current, diagnosed psychological illnesses, such as bipolar disorder, obsessive-compulsive disorder, schizophrenia or another psychological problem.

All subjects will be asked to complete a Health Status Questionnaire asking about their basic health history, any past anxiety experiences or depressive episodes, and various family illnesses. This is done in order to control for problems that may already be in someone's past or that may run in their family, and to determine whether anxiety or depression was or may be a background problem or family problem for any of the volunteers. In addition, the individuals who participate in this study will be informed in writing that this study is done with their consent as volunteers, and that they do not have to answer any question or perform any test that makes them uncomfortable. They will be able to leave the study at any time without any penalty if they determine that they are not comfortable with the requirements of the study.

Procedure and design

The subjects' diets will be monitored with their consent upon their beginning participation in the study. The subjects will then be fed all of their meals at the clinic, and each one of these meals will be designed so that each subject each day meets the 35% fat and 3500 calorie range. For volunteers to be good candidates for participation in the study, they need to live close to the clinic and/or be willing to come there every day, three times a day, for eight consecutive weeks, in order to ensure that they are getting a specific amount of fat and calories. Every Wednesday, the volunteers in the study will come in after they have eaten their dinner, and they will then be asked to perform various tests and self-assessments. The blood of each volunteer will be drawn during this time in order to measure their serotonin levels. The level of serotonin in a person's blood is believed to be a direct indicator of whether that person is depressed. The higher the level of serotonin, the lower the level of depression that an individual allegedly feels.

There will also be a 10 to 15 minute Center for Epidemiological Studies Depression Scale (CES-D) given and tracked, and the volunteers will answer the questions on the Beck Depression Inventory. In the Beck Depression Inventory patients are diagnosed as having a major depression if they have at least one core symptom such as depressed mood or loss of interest and at least four other symptoms (Lewis & Cachelin, 2001). If a subject is diagnosed with minor depression, this means that they have at least one core symptoms and two additional symptoms, but a total symptom quantity of less than five. This statistical tool has been around for some time, and is particularly significant in determining both the rate of depression and the severity of it (Hewitt, et al., 2001).

The STAI (a test for anxiety) will also be recorded at that time. Both transient (such as panic attacks) and enduring (such as chronic anxiety disorders) levels of anxiety are measured with the STAI. In the STAI, the researcher asks the subjects how they feel at the moment and in the recent past, and how they anticipate feeling in the future (Benazon & Coyne, 2000). This test is designed to overlap between depression and anxiety scales by measuring the most common anxiety symptoms which are minimally shared with depression (American, 1994). Both physiological and cognitive components of anxiety are addressed in the 21 items describing subjective, somatic, or panic-related symptoms (Kingsbury & Williams, 2003).

Once those tests are completed, the volunteers will be asked to cycle on an ergometer for 30 minutes. The Talk Test, Target Heart Rate Evaluation, and the Borg Rating of Perceived Exertion Scale will all be administered while the volunteer is cycling. This is done to determine the energy level - or the perceived energy level - of the volunteer. All of these tests and this same specific pattern will be repeated throughout the entire study, which is eight weeks in length.

Dependent Variable

Depression is a dependent variable, and it will be checked in three different ways: a neurotransmitter-level monitoring test, a symptom-based test, and a self-assessment test.

The amount of serotonin in the blood is a good indicator of normal and above normal thresholds of the key neurotransmitter linked to depression, serotonin. This chemical, typically found in the brain, can be boosted in many ways, including anti-depressant medication, certain foods, and exercise (Dietz, 2002). It is important to be aware, however, that it is not the only neurotransmitter linked to depression, and some people with normal serotonin levels are still depressed.

Analysis

In order to analyze the information collected, a combination of qualitative and quantitative methods will be addressed. This combination will allow the researcher to analyze the statistical information - such as the blood levels of serotonin, the volunteers' heart rate during the cycle test, and other hard data. However, the researcher will also be able to address the feelings and thoughts of the volunteers in order to determine whether these individuals think that they are depressed. It is possible that statistical tools such as the Beck Depression Inventory will show a person to be depressed when in fact that person does not feel as though he or she is anything other than 'normal' (Kowner, 2002).