The Comprehensive Guide to Intermittent Fasting: Benefits, Risks, and Personal Insights

Out of all the diets out there in the health and fitness world, I don’t think there is a “diet” that is as widely discussed, debated, (and misunderstood) as Intermittent Fasting. So, what is Intermittent Fasting, and why is it worth your attention? 

Intermittent Fasting (IF) has surged in popularity as a seemingly straightforward path to improved health and weight management. Unlike traditional diets that dictate what you eat, IF focuses on when you eat, presenting a unique approach to calorie restriction and its associated benefits. At its core, IF is just another method to reduce calorie consumption, but it also offers unique health benefits beyond simple calorie restriction, thanks to the biological adaptations that are elicited from fasting. 

However, like any dietary strategy, it comes with its nuances, potential risks, and considerations. In this comprehensive guide, we’ll delve into the scientific underpinnings of IF, explore its benefits and risks, discuss who it’s for (and who it’s not for), and share personal insights to help you understand whether IF might be right for you.

Health Benefits of Caloric Restriction

Before we dive deeper, let’s establish a fundamental truth: the only method for weight loss backed by solid scientific evidence is caloric restriction. This approach, which involves reducing your daily calorie intake so that you expend more calories than you consume, is not just about shedding pounds—it’s a cornerstone of health, offering wide-ranging benefits that bolster both general well-being and specific health outcomes:

  • Weight Loss and Improved Body Composition: By initiating a calorie deficit, caloric restriction compels the body to burn stored fat for energy. The result? Not only do you lose weight, but you also see significant improvements in body composition and a reduction in fat mass.
  • Enhanced Metabolic Health: Adopting a regimen of regular caloric restriction can markedly improve key indicators of metabolic health. This includes lowering blood sugar levels and boosting insulin sensitivity, thus diminishing the risk of developing type 2 diabetes.
  • Cardiovascular Benefits: Lowering your calorie intake is linked to vital improvements in cardiovascular health markers—lower blood pressure and better cholesterol profiles, to name a couple. These shifts are crucial for reducing the likelihood of heart disease.
  • Longevity: There’s growing evidence to suggest that caloric restriction could lead to a longer life. The theory here is that cutting down on calorie intake reduces metabolic stress, which in turn slows down the aging process and promotes cellular repair.

The myriad benefits of caloric restriction are extensively documented, underpinning numerous dietary guidelines aimed at fostering health improvement and promoting longevity.

Intermittent Fasting: A Different Take on Caloric Restriction

Intermittent fasting (IF) offers a novel approach to creating a caloric deficit by narrowing the timeframe in which food intake is allowed. This method naturally curtails calorie consumption without the meticulous counting and tracking associated with traditional dieting. For many, IF proves to be a more sustainable and psychologically gratifying method than the constant vigilance over calories that conventional diets demand. Beyond the general health benefits of caloric restriction, IF introduces several unique advantages:

  • Improved Metabolic Health: A pivotal study by Varady et al. (2013) in the American Journal of Clinical Nutrition highlighted that IF could significantly improve insulin sensitivity and lead to weight loss, particularly in obese adults. This improvement in metabolic health is crucial for reducing the risk of type 2 diabetes and other metabolic disorders.
  • Enhanced Cellular Repair: Research by Alirezaei et al. (2010) in Autophagy found that fasting triggers autophagy, a process where cells digest and remove old and dysfunctional proteins. This process is vital for cellular repair and maintenance, offering protective benefits against diseases, including neurodegenerative conditions and cancer.
  • Boosted Cardiovascular Health: A study published in JAMA Internal Medicine by Horne et al. (2016) demonstrated that routine periodic fasting could lower the risk of coronary artery disease and diabetes, alongside significant improvements in cholesterol levels. These findings suggest that IF may contribute to better heart health.
  • Elevated Mental Clarity: Prolonged fasting is linked to increased mental clarity and cognitive function, thanks to the production of ketones. This mental sharpness, a hallmark of IF, is not typically seen with regular meal consumption.

In essence, while both eating strategies enhance health through caloric restriction, intermittent fasting stands out by offering specific benefits that impact metabolic health, cellular repair, heart health, and cognitive function in distinct ways. Despite the added health benefits of IF, it is important to take into account the potential drawbacks of this sort of eating style.

Potential Risks and Considerations

While the benefits of IF are compelling, it’s essential to approach this dietary pattern with awareness of its potential drawbacks:

  • Risk of Overeating: There’s a possibility of overeating during eating periods, which can negate the calorie deficit achieved through fasting. This requires mindful eating practices to ensure the benefits of IF are realized.
  • Nutrient Deficiency: IF can lead to nutrient deficiencies if not carefully planned, especially with restrictive eating windows. Ensuring a balanced intake of nutrients during eating periods is crucial.
  • Difficulty Meeting Protein Requirements: For active individuals who are conscious about their muscle mass & lean body composition, IF makes it substantially more difficult to ingest enough protein to support an anabolic environment for muscle tissue and development.
  • Disordered Eating Patterns: For some, IF may exacerbate or lead to disordered eating habits. It’s important for individuals with a history of eating disorders to proceed with caution and seek professional guidance.
  • Fluctuating Energy Levels: The fasting component of IF can lead to periods of low energy, especially during the initial adjustment phase or on longer fast days. This can impact daily activities and exercise performance.
  • Mood Swings: The changes in eating patterns can also affect mood, leading to irritability or mood swings in some individuals. Being aware of and prepared for potential emotional fluctuations is important.
  • Effects on Women: Research indicates that IF might impact women differently, potentially affecting menstrual cycles and fertility. Women considering IF should consult with healthcare providers to tailor the approach to their specific health needs. (More on that below.)

Intermittent Fasting Protocols

Intermittent fasting encompasses a variety of different methods, each with its own rules about when to eat and when to fast. Here’s an overview of the most well-known and researched fasting protocols:

  • Time-Restricted Eating (TRE): This method involves restricting your eating window to a certain number of hours per day.  For example, the most common fasting-to-eating ratio we see is the 16/8 structure.  Other methods go as “low” as a 14/10 ratio, and as “high” as 18/6.
  • 5:2 Diet (Fast Diet): The 5:2 Diet involves eating normally for five days of the week and eating no more than 500 calories on the other two, non-consecutive days.
  • Eat-Stop-Eat: This involves a 24-hour fast once per week. The most common example is fasting from dinner one day until dinner the next day.
  • Alternate-Day Fasting (ADF): As the name suggests, you fast every other day. There are several variations of this method. Some allow about 500 calories during the fasting days, while others recommend no calories at all.
  • OMAD (One Meal A Day): This form of intermittent fasting involves consuming only one meal a day, thus fasting for 20+ hours daily.

Women and Intermittent Fasting

Before I comment on women and intermittent fasting, I just want to throw out the caveat that I am, by no means, an expert on women and women’s health. BUT (in the words of Ned Stark, “everything before ‘but’ is bullshit”) it has always seemed strange to me that every article I have ever read on IF will apply the caveat “but it doesn’t really work for women,” and then never goes into detail as to why it doesn’t work well for women. I am not going to dive deep into this topic, as this could be an article in and of itself, but I want to at least mention it.

While intermittent fasting (IF) is lauded for its health perks, such as weight loss and mental clarity boosts, it’s vital to acknowledge that IF might present unique challenges for women. This is largely due to the delicate balance of hormones and reproductive health considerations that are intrinsic to a woman’s body. Recognizing that women might need to tailor IF to fit their unique physiological makeup underscores the importance of a personalized approach.

Women and Hormone Sensitivities

Women’s bodies react sensitively to dietary changes, including those involved in calorie restriction and fasting. This reaction significantly involves key hormones—like leptin (which helps regulate energy balance), ghrelin (the “hunger hormone”), insulin (which helps manage blood sugar levels), and essential reproductive hormones estrogen and progesterone. These hormones play critical roles not just in managing hunger, but in menstrual health, fertility, and overall metabolic functioning. As such, jumping into prolonged fasting without consideration of a woman’s menstrual cycle can be particularly tricky for women. There’s growing conversation around aligning IF practices with the cycle to potentially enhance IF’s benefits and mitigate discomfort. Here is a dumbed down version of what a fasting schedule, aligned with a woman’s cycle, might look like:

  • Early Phase (Day 1-14): Longer fasting seems appropriate during this phase of the cycle.

  • Ovulatory Phase (Day 14-16): Shorter fasting periods seem appropriate during this phase.

  • Later Phase (Day 17-28): Long fasts during this phase seem contraindicative to this part of the cycle, so probably ditch it altogether.

Listening to Your Body 

The golden rule for women exploring IF is to pay close attention to how their body responds. Experiences of increased fatigue, mood fluctuations, or menstrual irregularities signal a need to reassess the fasting approach. While research into IF’s effects on women is ongoing, the narrative suggests promise—with a side of caution. Especially for those managing specific health conditions or focusing on reproductive health, getting professional medical advice before embarking on IF is wise.

(Author’s Note: My insights into women’s health and IF are based on broader readings and should not replace professional advice. For a deeper dive, consider “In the Flo” by Alisa Vitti, which offers extensive insights into aligning diet with the female hormonal cycle.)

Why Try Intermittent Fasting

Intermittent fasting is more than a dietary trend; it’s a lifestyle adjustment with potential benefits that reach far beyond mere weight loss:

  • Health Benefits: IF transcends the traditional approach to dieting by offering enhancements in metabolic health, such as improved insulin sensitivity and lowered blood sugar levels, which contribute to a reduced risk of chronic diseases. Additionally, many adopters of IF report a decrease in inflammation markers.
  • Mental Clarity and Cognitive Benefits: A notable perk of IF is the increase in mental clarity and cognitive function experienced by many during fasting periods. This improvement is often attributed to the body’s increased ketone production when in a fasted state.
  • Simplicity and Flexibility: IF stands out for its simplicity, potentially eliminating the need for meticulous meal planning and calorie counting. Its flexibility also shines, with various fasting protocols to suit different lifestyles and preferences, making it adaptable and accessible for a broad audience.

Who Should Consider Intermittent Fasting (and Who Should Be Cautious)

IF May Be Suitable For:

  • Those Aiming for Weight Loss: Individuals targeting weight loss might find IF’s structured eating windows an effective strategy to achieve a calorie deficit.
  • Seekers of Metabolic Improvements: People at risk for or managing metabolic syndromes could benefit from IF’s positive effects on insulin sensitivity and blood glucose levels.
  • Proponents of Dietary Simplicity: For those overwhelmed by complex diet regimes, IF offers a refreshingly straightforward approach to health and wellness.

IF May Not Be Suitable For:

  • Certain Women: Women, particularly those focusing on fertility, pregnant, or breastfeeding, should exercise caution with IF due to its potential effects on hormonal balance.
  • High-Demand Athletes: Professional athletes or individuals with intense physical training routines may find that IF conflicts with their high caloric and nutritional requirements.
  • Individuals Prone to Eating Disorders: For those with a history of eating disorders, IF could risk rekindling unhealthy eating habits or thoughts.
  • People with Specific Health Conditions: Individuals managing conditions like diabetes or low blood pressure, or those on medications necessitating food intake, should consult healthcare professionals before embracing IF.

Personal Insights on Intermittent Fasting

In 2007, during my sophomore year of college, I ventured into intermittent fasting to cut weight for my first Mixed Martial Arts fight. The results were impressive: I shed 15 pounds in four months, managed to keep most of my muscle mass intact, and achieved a body fat percentage just under 8%. True, there was a slight dip in my strength and performance, likely a side effect of the weight loss, but the trade-off was worth it. IF proved to be the most straightforward and effective dietary strategy I had ever employed to maintain leanness and fitness. Seventeen years later, and I’ve consistently hovered around 150 pounds with less than 10% body fat, all thanks to intermittent fasting.

From a personal perspective, IF has been a revolutionary shift from the traditional dogma of consuming multiple small meals throughout the day (and never feeling satiated or satisfied). It caters perfectly to those, like me, who don’t have the time to prepare & eat multiple meals, too. To me, IF stands out as not only a satisfying way to regulate calorie intake but also allows for indulgence in meals without the perpetual worry over portion sizes. It’s been a game-changer in managing my dietary habits, offering a blend of discipline and dietary freedom that have become a pillar in my health and fitness journey.

Embracing Calorie Restriction Through IF

At its essence, IF is a strategic form of calorie restriction. It simplifies the process of reducing calorie intake by limiting the time frame in which food is consumed, rather than obsessing over the calorie content of every meal. This approach can lead to a more natural and less stressful way to achieve a calorie deficit and, consequently, weight loss.


Intermittent fasting presents a fascinating alternative to traditional diets, backed by science and validated by personal experiences. However, it’s not a one-size-fits-all solution. Considering the potential risks and consulting with healthcare professionals is essential before embarking on this dietary journey. By understanding both the scientific evidence and personal anecdotes, individuals can make informed decisions about incorporating IF into their lives for health and wellness. Remember, the key to successful dietary changes is finding a method that fits your lifestyle, preferences, and health needs. Whether IF is that method depends on a careful consideration of its benefits and risks, alongside personal compatibility with this unique approach to eating.


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