Scientific Online Resource System

Conference Proceedings

Critical Analysis of Intermittent Fasting

Dimitar Marinov, Darina Naydenova


Introduction: Intermittent fasting (IF) is an alternative dietary pattern that imposes the complete or partial restriction of all sources of calories for a specific period in time. In-between these periods there is a restricted time window to consume calories in the form of food, drinks, etc. IF is one of the most popular regimens amongst dieters worldwide. Despite the popularity of this dietary pattern, there are plenty of misconceptions regarding both the benefits and health risks of IF.

Review Results: Intermittent fasting does not appear to produce any metabolic advantages or disadvantages compared to other methods for calorie restriction despite the effects on hormones, meal skipping, and the effect of continuous fasting on energy expenditure. It is as effective as continuous energy restriction in improving body weight and cardiovascular risk factors. IF might also provide benefits against oxidative stress and inflammation. Its effect on autophagy is not yet investigated in humans. Despite the benefits for weight loss and metabolic health, certain population groups such as women with normal and low body weight might experience worsened glucose tolerance due to fasting. There is also a risk for hypotonia, hypoglycemia, menstrual problems, and others.

Conclusion: IF is as effective as continuous calorie restriction and there do not appear to be any metabolic advantages or disadvantages related to fasting. Long-term adherence might be an issue for a significant percentage of dieters. Currently, there is a lack of evidence for the long-term safety and effectiveness of IF regimens.


intermittent fasting, weight loss, metabolic effect, alternate-day fasting, health risks

Full Text


International Food Information Council (2019). Food and health survey.

Retrieved from:

French, S. A., Jeffery, R. W., & Murray, D. (1999). Is dieting good for you?: Prevalence, duration and associated weight and behaviour changes for specific weight loss strategies over four years in US adults. International journal of obesity and related metabolic disorders: journal of the International Association for the Study of Obesity, 23(3), 320–327.

Hartman, M. L., Veldhuis, J. D., Johnson, M. L., Lee, M. M., Alberti, K. G., Samojlik, E., & Thorner, M. O. (1992). Augmented growth hormone (GH) secretory burst frequency and amplitude mediate enhanced GH secretion during a two-day fast in normal men. The Journal of clinical endocrinology and metabolism, 74(4), 757–765.

Seimon, R. V., Roekenes, J. A., Zibellini, J., Zhu, B., Gibson, A. A., Hills, A. P., Wood, R. E., King, N. A., Byrne, N. M., & Sainsbury, A. (2015). Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials. Molecular and cellular endocrinology, 418 Pt 2, 153–172.

Watanabe, Y., Saito, I., Henmi, I., Yoshimura, K., Maruyama, K., Yamauchi, K., Matsuo, T., Kato, T., Tanigawa, T., Kishida, T., & Asada, Y. (2014). Skipping Breakfast is Correlated with Obesity. Journal of rural medicine : JRM, 9(2), 51–58.

Sievert, K., Hussain, S. M., Page, M. J., Wang, Y., Hughes, H. J., Malek, M., & Cicuttini, F. M. (2019). Effect of breakfast on weight and energy intake: systematic review and meta-analysis of randomised controlled trials. BMJ (Clinical research ed.), 364, l42.

Nair, K. S., Woolf, P. D., Welle, S. L., & Matthews, D. E. (1987). Leucine, glucose, and energy metabolism after 3 days of fasting in healthy human subjects. The American journal of clinical nutrition, 46(4), 557–562.

Mansell, P. I., Fellows, I. W., & Macdonald, I. A. (1990). Enhanced thermogenic response to epinephrine after 48-h starvation in humans. The American journal of physiology, 258(1 Pt 2), R87–R93.

Zauner, C., Schneeweiss, B., Kranz, A., Madl, C., Ratheiser, K., Kramer, L., Roth, E., Schneider, B., & Lenz, K. (2000). Resting energy expenditure in short-term starvation is increased as a result of an increase in serum norepinephrine. The American journal of clinical nutrition, 71(6), 1511–1515.

Patel, J. N., Coppack, S. W., Goldstein, D. S., Miles, J. M., & Eisenhofer, G. (2002). Norepinephrine spillover from human adipose tissue before and after a 72-hour fast. The Journal of clinical endocrinology and metabolism, 87(7), 3373–3377.

Harris, L., Hamilton, S., Azevedo, L. B., Olajide, J., De Brún, C., Waller, G., Whittaker, V., Sharp, T., Lean, M., Hankey, C., & Ells, L. (2018). Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis. JBI database of systematic reviews and implementation reports, 16(2), 507–547.

Cioffi, I., Evangelista, A., Ponzo, V., Ciccone, G., Soldati, L., Santarpia, L., Contaldo, F., Pasanisi, F., Ghigo, E., & Bo, S. (2018). Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials. Journal of translational medicine, 16(1), 371.

Headland, M., Clifton, P. M., Carter, S., & Keogh, J. B. (2016). Weight-Loss Outcomes: A Systematic Review and Meta-Analysis of Intermittent Energy Restriction Trials Lasting a Minimum of 6 Months. Nutrients, 8(6), 354.

Del Corral, P., Bryan, D. R., Garvey, W. T., Gower, B. A., & Hunter, G. R. (2011). Dietary adherence during weight loss predicts weight regain. Obesity (Silver Spring, Md.), 19(6), 1177–1181.

Johnstone, A. M., Faber, P., Gibney, E. R., Elia, M., Horgan, G., Golden, B. E., & Stubbs, R. J. (2002). Effect of an acute fast on energy compensation and feeding behaviour in lean men and women. International journal of obesity and related metabolic disorders: journal of the International Association for the Study of Obesity, 26(12), 1623–1628.

Heilbronn, L. K., Smith, S. R., Martin, C. K., Anton, S. D., & Ravussin, E. (2005). Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism. The American journal of clinical nutrition, 81(1), 69–73.

Horne, B. D., Muhlestein, J. B., & Anderson, J. L. (2015). Health effects of intermittent fasting: hormesis or harm? A systematic review. The American journal of clinical nutrition, 102(2), 464–470.

Antunes, F., Erustes, A. G., Costa, A. J., Nascimento, A. C., Bincoletto, C., Ureshino, R. P., Pereira, G., & Smaili, S. S. (2018). Autophagy and intermittent fasting: the connection for cancer therapy?. Clinics (Sao Paulo, Brazil), 73(suppl 1), e814s.

Alirezaei, M., Kemball, C. C., Flynn, C. T., Wood, M. R., Whitton, J. L., & Kiosses, W. B. (2010). Short-term fasting induces profound neuronal autophagy. Autophagy, 6(6), 702–710.

Johnson, J. B., Summer, W., Cutler, R. G., Martin, B., Hyun, D. H., Dixit, V. D., Pearson, M., Nassar, M., Telljohann, R., Maudsley, S., Carlson, O., John, S., Laub, D. R., & Mattson, M. P. (2007). Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma. Free radical biology & medicine, 42(5), 665–674.

Faris, M. A., Kacimi, S., Al-Kurd, R. A., Fararjeh, M. A., Bustanji, Y. K., Mohammad, M. K., & Salem, M. L. (2012). Intermittent fasting during Ramadan attenuates proinflammatory cytokines and immune cells in healthy subjects. Nutrition research (New York, N.Y.), 32(12), 947–955.

Aksungar, F. B., Topkaya, A. E., & Akyildiz, M. (2007). Interleukin-6, C-reactive protein and biochemical parameters during prolonged intermittent fasting. Annals of nutrition & metabolism, 51(1), 88–95.

Heilbronn, L. K., Civitarese, A. E., Bogacka, I., Smith, S. R., Hulver, M., & Ravussin, E. (2005). Glucose tolerance and skeletal muscle gene expression in response to alternate day fasting. Obesity research, 13(3), 574–581.

Kumar, S., & Kaur, G. (2013). Intermittent fasting dietary restriction regimen negatively influences reproduction in young rats: a study of hypothalamo-hypophysial-gonadal axis. PloS one, 8(1), e52416.

Hoddy, K. K., Kroeger, C. M., Trepanowski, J. F., Barnosky, A. R., Bhutani, S., & Varady, K. A. (2015). Safety of alternate day fasting and effect on disordered eating behaviors. Nutrition journal, 14, 44.


Font Size