Discussion Paper on Diet and Weight Loss
In order to get valid and relevant results from articles comparing the effectiveness of diet and exercise alone in achieving and maintaining weight loss, the procedures of research and analysis in these articles have to meet fundamental scientific standards. These standards include the use of a large, representative sample, implementation of a randomized control design of research, and identification of study limitations. The first standard of use of a large representative sample was present in one of the five articles used in the PICOT project. The article by Johns et al. (2014) featured the use of eight studies that represented 1.022 participants, while those by Manikam et al. (2018), Yancy Jr. et al. (2004), Clark (2015), and Castro et al. (2018) utilized samples of two studies, 120 participants, 66 population-based studies, and 20 participants respectively. The randomized controlled design, which is important to reduce specific sources of bias in tests of the effectiveness of treatments, was present in the articles by Clark (2015), Yancy Jr. et al. (2004), Manikam et al. (2018), and Johns et al. (2014), while the article by Castro et al. (2018) applied an experimental design with no control. The articles by Castro et al. (2018), Yancy Jr. et al. (2004), and Johns et al. (2014) identified the gaps and study limitations, while the other two by Manikam et al. (2018) and Clark (2015) did not.
The use of original research was a key strength in the articles by Castro et al. (2018) and Yancy Jr. (2004). In the other three articles, the researchers utilized systematic research and meta-analytic research approaches, such that their findings and conclusions were dependent on the accuracy and validity of other researchers’ methods. Overall, the five articles presented a credible guiding assessment of the effectiveness of a ketogenic diet alone relative to a combined diet and exercise program for weight loss. While three of the articles utilized systematic research and meta-analytic approaches, it is notable that this approach enabled the researchers to utilize larger samples of study that were more representative and provided a more balanced guiding assessment of this central question in the PICOT project.
Castro, A., Gomez-Arbelaez, D., Crujeiras, A., Granero, R., Aguera, Z., Jimezez-Murcia, S., Sajoux, I., Lopez-Jaramillo, P., Fernandez-Aranda, F., & Casanueva, F. (2018). Effect of a very low-calorie ketogenic diet on food and alcohol cravings, physical and sexual activity, sleep disturbances, and quality of life in obese patients. Nutrients 10: 1-19.
Clark, J. (2015). Diet, exercise or diet with exercise: comparing the effectiveness of treatment options for weight-loss and changes in fitness for adults (18–65 years old) who are overfat, or obese; systematic review and meta-analysis. Journal of Diabetes and Metabolic Disorders 14: 1-28.
Johns, D., Hartmann-Boyce, J., Jebb, S., & Aveyard, P. (2014). Diet or exercise interventions vs combined behavioral weight management programs: A systematic review and meta-analysis of direct comparisons. Journal of the Academy of Nutrition and Dietetics 1557-1568.
Manikam, N., Pantoro, N., Komala, K., & Sari, A. (2018). Comparing the efficacy of a ketogenic diet with low fat diet for weight loss in obesity patients: Evidence-based case report. World Nutrition Journal 2(1): 7-14.
Yancy Jr., W., Olsen, M., Guyton, J., Bakst, R., & Westman, E. (2004). A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and Hyperlipidemia: A randomized, controlled trial. Annals of Internal Medicine 140 (10): 769-777.