Intermitting Fasting Fad or Not?
Image Credit: Pexels.com Oladimeji Ajegbile
Intermittent fasting (IF) also known as time restricted eating is where you restrict your eating to a maximum window of hours in a day. Over the last few years particularly there has been a lot said about this form of eating, mainly around the topic of weight loss and it is currently one of the world’s most popular health trends. As you probably already know if you follow my blog or my instagram I am not a fan of fad diets as they are just that. Intermittent fasting, however, shows no sign of going out of fashion soon – could this be because unlike other “fad” diets this way of eating is actually beneficial? In this post I review the evidence for the multitude of benefits this style of eating is said to exhibit, question whether this is actually just another fad diet and help you question whether this style of eating is right for you.
Firstly, I think we need to consider where this style of eating originated and the research behind it. One could consider that everyone tends to observe some form of IF, for the majority of us the greatest example of this is when we sleep, hence the term “break” - “fast” (1). But a better example of IF that is closer to that which is discussed and talked about in media (the 16/8 method - 16 hours of fasting) would include religious observations such as Ramadan. As such not surprisingly much of the initial research into IF was conducted using those observing these short-term practices (2-4).
So what have the findings been and is it all about weight loss? Research into IF has suggested it can lead to several changes in the body that may not only support weight loss but could also be preventative against and help support those suffering with type 2 diabetes and high cholesterol levels (5-9). IF also appears to have a positive impact on inflammatory and oxidative stress markers (10). These are often found high in numerous conditions including autoimmune conditions, CFS and fibromyalgia but are also linked to ageing. IF even shows potential in positively impacting conditions such as Alzheimer's and Parkinson’s disease (11-12).
When it comes to weight loss it is worth considering that the majority of the research has been conducted in those who are classified as obese although it has been seen to be successful in the short-term for weight loss among non-obese individuals in some studies (5,13). Surprisingly, IF has achieved similar results to those observed during continued energy restriction diets and may reduce the physiological effects that are observed in these diets that can hinder weight loss, this is due to the results coming from changes in hormone levels and not restriction (14). And lets be honest it is rather simple to follow as it doesn’t specify which foods you should eat but rather when you should eat them, so it is no wonder this style of eating is so popular.
Is the 16/8 method the way to go?
It needs to be considered that research shows positive effects from just 10 hours of fasting, so is 16 hours really needed? 16/8 may not only be hard to maintain but minimal evidence exists regarding long-term efficacy furthermore, studies are generally only short in their length and more studies are required to assess the long-term effects of adapting the 16/8 way of eating (15). Many IF structures also suggest you delay breakfast however, if we actually look at the evidence breakfast supports cardiometabolic health (16). As such considering the evidence I would always suggest 12 to 14 hour fasts and potentially the Crescendo Method (fasting 2-3 alternate days per week) particularly as you begin this way of eating as your body will still require some time to adapt and it should be more sustainable while still providing you with all the benefits of this way of eating. In fact, if you think about it is this not the way we evolved to eat?
So I actually challenge you to question if this actually is a fad diet, a new way of eating or the way humans evolved to consume food prior to food being so readily available 24hours a day. Also whether this “normal” way of eating is potentially being taken too far by some.
Is this form of eating for everyone?
Absolutely not! This style of eating may not be suitable for, people who are suffering with acid reflux or gurd this could make their condition worse negatively impacting their health (17). Or those who are not eating large meals due to a reduced appetite caused by medications or conditions as well as pregnant or lactating women, those taking certain medications, those underweight or with a history of disordered eating to name but a few. It also does not work for everyone!
This is why consulting a professional and discussing it with your doctor is essential when it comes to making changes like this to your diet and way of eating. One of the main reasons I entered the world of Nutritional Therapy is it treats everyone as individuals; practitioners are trained to assess your individual needs, medical conditions, lifestyles, likes and dislikes as nutritional requirements are so personal and one size certainly does not fit all. It is worth remembering that the best thing you can do to improve your nutrition without the aid of a professional is aim to eat a balanced diet.
Stay happy and healthy,
Chel
References:
(1) Anderson, Heather Arndt (2013). Breakfast: A History. AltaMira Press.
(2) Zouhal, H. et al., 2020. Effects of Ramadan Intermittent Fasting on Gut Hormones and Body Composition in Males with Obesity. International Journal of Environmental Research and Public Health, 17(15), p.5600.
(3) Koufakis, T., Karras, S.Ν., Antonopoulou, V., Angeloudi, E., Zebekakis, P. and Kotsa, K., 2017. Effects of Orthodox religious fasting on human health: a systematic review. European journal of nutrition, 56(8), pp.2439-2455.
(4) Persynaki, A., Karras, S. and Pichard, C., 2017. Unraveling the metabolic health benefits of fasting related to religious beliefs: A narrative review. Nutrition, 35, pp.14-20.
(5) Harris, L., Hamilton, S., Azevedo, L.B., Olajide, J., De Brún, C., Waller, G., Whittaker, V., Sharp, T., Lean, M., Hankey, C. and Ells, L., 2018. Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis. JBI Evidence Synthesis, 16(2), pp.507-547.
(6) Cho, Y., Hong, N., Kim, K.W., Lee, M., Lee, Y.H., Lee, Y.H., Kang, E.S., Cha, B.S. and Lee, B.W., 2019. The effectiveness of intermittent fasting to reduce body mass index and glucose metabolism: a systematic review and meta-analysis. Journal of clinical medicine, 8(10), p.1645.
(7) Halberg, N., Henriksen, M., Söderhamn, N., Stallknecht, B., Ploug, T., Schjerling, P. and Dela, F., 2005. Effect of intermittent fasting and refeeding on insulin action in healthy men. Journal of applied physiology.
(8) Horne, B.D., Muhlestein, J.B. and Anderson, J.L., 2015. Health effects of intermittent fasting: hormesis or harm? A systematic review. The American journal of clinical nutrition, 102(2), pp.464-470.
(9) Meng, H., Zhu, L., Kord-Varkaneh, H., Santos, H.O., Tinsley, G.M. and Fu, P., 2020. Effects of intermittent fasting and energy-restricted diets on lipid profile: a systematic review and meta-analysis. Nutrition, 77, p.110801.
(10) Mo'ez Al-Islam, E.F., Jahrami, H.A., Obaideen, A.A. and Madkour, M.I., 2019. Impact of diurnal intermittent fasting during Ramadan on inflammatory and oxidative stress markers in healthy people: Systematic review and meta-analysis. Journal of Nutrition & Intermediary Metabolism, 15, pp.18-26.
(11) Bredesen, D.E., 2014. Reversal of cognitive decline: a novel therapeutic program. Aging (Albany NY), 6(9), p.707.
(12) Zhou, Z.L., Jia, X.B., Sun, M.F., Zhu, Y.L., Qiao, C.M., Zhang, B.P., Zhao, L.P., Yang, Q., Cui, C., Chen, X. and Shen, Y.Q., 2019. Neuroprotection of fasting mimicking diet on MPTP-induced Parkinson’s disease mice via gut microbiota and metabolites. Neurotherapeutics, 16(3), pp.741-760.
(13) Ganesan, K., Habboush, Y. and Sultan, S., 2018. Intermittent fasting: the choice for a healthier lifestyle. Cureus, 10(7).
(14) 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. and 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, pp.153-172.
(15) Jospe, M.R. et al., 2020. Intermittent fasting, Paleolithic, or Mediterranean diets in the real world: exploratory secondary analyses of a weight-loss trial that included choice of diet and exercise. The American journal of clinical nutrition, 111(3), pp.503-514.
(16) St-Onge, M.P., Ard, J., Baskin, M.L., Chiuve, S.E., Johnson, H.M., Kris-Etherton, P. and Varady, K., 2017. Meal timing and frequency: implications for cardiovascular disease prevention: a scientific statement from the American Heart Association. Circulation, 135(9), pp.e96-e121.
(17) Hamdan, A.L., Nassar, J., Dowli, A., Al Zaghal, Z. and Sabri, A., 2012. Effect of fasting on laryngopharyngeal reflux disease in male subjects. European Archives of Oto-Rhino-Laryngology, 269(11), pp.2361-2366.