Intermittent fasting is unlikely to be news to you by now. It has gained considerable attention in recent years as a promising dietary strategy for improving health, promoting weight loss, and potentially extending lifespan. While it may seem like a trendy diet fad, the concept of intermittent fasting has deep roots in human history and is backed by a growing body of scientific research. From stabilizing blood sugar levels to boosting brain function, intermittent fasting has proven to be a lifestyle change with incredible advantages. However, like any diet change, it must be done correctly, and it may not apply to everyone. Let’s delve into the science behind intermittent fasting, examining its potential benefits and exploring the various methods of implementation.
Intermittent Fasting & Blood Sugar Benefits
Blood sugar regulation is crucial for maintaining overall health, preventing chronic diseases, and improving life expectancy and longevity. Intermittent fasting has been proven by numerous studies to have significant benefits on glucose control and insulin resistance.
At a certain point when we fast, our body goes into a state of ketosis, where it starts to use stored fat as fuel instead of glucose. This shift in energy metabolism helps regulate blood sugar levels by reducing insulin resistance and decreasing fat-based body mass.
Additionally, intermittent fasting promotes the release of a special hormone known as adiponectin, which plays a crucial role in regulating blood sugar levels. Higher adiponectin levels have been linked to better insulin sensitivity as well as lower risk of developing diabetes.
Intermittent Fasting & Inflammation Benefits
Inflammation is among the body's natural responses to protecting against foreign invaders and healing damaged tissues. However, chronic inflammation causes various health issues, such as arthritis, heart disease, autoimmunity, and even cancer.
One key benefit of intermittent fasting is its ability to reduce inflammation in the body. When we fast, our body enters a state called autophagy (1), where it starts breaking down old cells and repairing damaged ones. This process helps eliminate toxins, waste products, damaged cells and proteins, which overall help to reduce inflammation.
Intermittent Fasting & Memory and Mood Benefits
Memory and mood play a crucial role in our overall well-being. Intermittent fasting has been found to be beneficial for both memory and mood.
When we fast intermittently, our brain undergoes certain physiological changes that can enhance cognitive function and boost memory. Research has shown that intermittent fasting stimulates the production of a protein called BNDF, or brain-derived neurotrophic factor, that promotes the growth of new neurons and strengthens existing ones (2).
However, most (if not nearly all) of these research studies were done in men. A number of studies conducted that included women have reported side effects, including hunger, mood swings, lack of concentration, reduced energy, and headaches on fasting days (3,4). It may also increase the risk of depression in both men and women (5). Modified methods of intermittent fasting (which we’ll discuss in a moment) should be considered for women.
Heart Health and Weight Loss Benefits
The cardiovascular system is critical for overall well-being, and intermittent fasting can significantly improve heart health. Fasting has been shown to not only reduce blood pressure levels but also prevent heart attacks due to its benefits of promoting weight loss. Excess weight stresses the cardiovascular system and increases the risk of conditions like coronary artery disease and myocardial infarction.
Furthermore, since intermittent fasting has been found to decrease inflammation in the body, it benefits the cardiovascular system by lowering the chronic inflammation that is closely linked to various heart diseases like atherosclerosis and congestive heart failure.
A Note on Intermittent Fasting in Women
Above and beyond the well-known benefits of intermittent fasting for weight loss, heart health and inflammation, there are some more unique considerations when we consider the totality of research and how it applies to intermittent fasting in women. Overall, the data is lacking. Most studies have been conducted exclusively in men. However, some literature on fasting in women highlights the following:
Hormonal Changes: Women experience hormonal fluctuations throughout their menstrual cycle, including changes in estrogen and progesterone levels. Some studies suggest that women's responses to fasting may vary depending on their menstrual phase. For instance, fasting during the luteal phase (the second half of the menstrual cycle) might be more challenging due to increased hunger and cravings.
Fertility and Reproductive Health: There are concerns about the impact of intermittent fasting on women's fertility and reproductive health. Extreme forms of intermittent fasting, especially those leading to rapid weight loss or very low-calorie intake, may disrupt the menstrual cycle and, in some cases, lead to amenorrhea (absence of menstruation). This can have implications for fertility and bone health.
The best approach to intermittent fasting for women generally considers a modified approach, such as the ‘Crescendo Method’ which involves fasting 12–16 hours for two to three days a week on non-consecutive days, for the ‘16/8 Method’ where fasting is done for 16 hours a day, and all calories are eaten within an eight-hour window. Women are advised to start with 14-hour fasts and eventually build up to 16 hours.
Intermittent fasting is incredibly powerful in offering numerous health benefits. From regulating blood sugar levels and reducing inflammation to improving memory and mood, the advantages of intermittent fasting are truly impressive.
With that being said, it's always best to listen to your body and consult a health expert before commencing any new diet/eating regimen or fasting program. There's more to intermittent fasting benefits than what's covered above. Most importantly, you need an intermittent fasting program crafted to match your body type, health, and special needs/lifestyle without exposing you to risks.
Pak M, Bozkurt S, Pınarbaşı A, Öz Arslan D, Aksungar FB. Effects of Prolonged Intermittent Fasting Model on Energy Metabolism and Mitochondrial Functions in Neurons. Ann Neurosci. 2022 Jan;29(1):21-31. doi: 10.1177/09727531211072303. Epub 2022 Feb 2. PMID: 35875426; PMCID: PMC9305913.
Seidler K, Barrow M. Intermittent fasting and cognitive performance - Targeting BDNF as potential strategy to optimise brain health. Front Neuroendocrinol. 2022 Apr;65:100971. doi: 10.1016/j.yfrne.2021.100971. Epub 2021 Dec 18. PMID: 34929259.
Heilbronn LK, Smith SR, Martin CK, Anton SD, Ravussin E. Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism. Am J Clin Nutr. 2005 Jan;81(1):69-73. doi: 10.1093/ajcn/81.1.69. PMID: 15640462.
Harris L, Hamilton S, Azevedo LB, Olajide J, De Brún C, Waller G, Whittaker V, Sharp T, Lean M, Hankey C, Ells L. Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis. JBI Database System Rev Implement Rep. 2018 Feb;16(2):507-547. doi: 10.11124/JBISRIR-2016-003248. PMID: 29419624.