Understanding Intermittent Fasting: The Basics, Benefits, and Drawbacks

Intermittent fasting (IF) transcends mere dietary change, morphing into a lifestyle choice that harmonizes with our body’s natural rhythms. This age-old practice, backed by emerging science, offers a structured approach to eating—alternating between periods of fasting and balanced meals. By delving into the interplay between IF, nutritional balance, and circadian rhythms, we unveil a holistic approach to health, paving the way for enhanced metabolic efficiency and overall well-being.

What’s in this article:

What is Intermittent Fasting: Defining the Diet

Intermittent Fasting (IF) is more than just a trending diet; it’s a transformative approach to eating. Instead of focusing on what to eat, IF emphasizes when to eat. By cycling between periods of eating and fasting, your body undergoes distinct metabolic shifts. Over time, these shifts can impact weight, health, and overall well-being. Studies have shown that not eating for specific blocks of time each day and greatly restricting calories a few times a week may have health benefits.

The routine is a contrast against the free-for-all eating during waking hours including multiple meals and snacking into the evenings and a return to our past of ending meals after a specific time until the following day when one “breaks fast” in the designated window. Essentially, time slots throughout the day and week are selected to be OK to eat and not OK to eat. At its core, the approach works by restriction calories consumed outside of the periods of the set time frames.

Intermittent fasting has surged in popularity, largely due to claims that it enhances physical health, increased stress resistance, increased longevity, and a decreased incidence of diseases, including cancer and obesity.1

How does the Intermittent Fasting approach work?

After hours without food the body runs out of sugar stores and starts burning stored fat. This process is called ketosis and triggers the same fat-burning process that occurs during a low-carbohydrate or keto diet. While it sounds straightforward, the body’s transition into and out of ketosis requires careful planning and understanding to maximize benefits and minimize potential drawbacks.2

The “metabolic switch” for your body to enter into ketosis can happen as quickly as 12 hours after not eating. This is when the body stops burning carbohydrates as fuel and begins using other stored energy sources such as fat.3 The switch paired with not resupplying the body with newly added energy sources (i.e., from other meals or snacks) forms the foundation for the health and weight loss effects of Intermittent Fasting.

What can you eat?

During the eating windows of Intermittent Fasting, there aren’t strict restrictions on what you can eat. However, for the most beneficial outcomes, it’s wise to opt for nutrient-dense foods that support your health goals. Lean proteins, whole grains, healthy fats, and a variety of fruits and vegetables should constitute the bulk of your diet. These foods provide the essential nutrients your body needs to function optimally, and they can help keep you satiated until your next eating window.

It’s also crucial to stay hydrated and to consider the timing of your meals. Eating a balanced meal that includes protein, fats, and carbohydrates can help maintain energy levels and curb hunger. Moreover, aligning your eating schedule with your natural circadian rhythm, such as having a hearty breakfast or lunch and a lighter dinner, can further enhance the benefits of Intermittent Fasting. This holistic approach ensures that your body receives the nourishment it needs while adhering to the fasting schedule.4

What can you not eat?

While Intermittent Fasting does not impose stringent rules on food types, it’s advisable to avoid or limit certain foods to reap the maximum benefits. Processed foods, sugary beverages, and high-fat junk food can derail your progress and negate the health advantages of fasting. These foods are often low in nutrients and high in empty calories, which can lead to overeating and eventual weight gain.

Moreover, it’s wise to minimize the consumption of alcohol and caffeine during your eating windows as they can disrupt your sleep and metabolic rhythm. Making healthier food choices and minimizing the intake of detrimental substances will significantly enhance your Intermittent Fasting experience. By adhering to a balanced and nutritious diet, you’re setting the stage for a successful fasting journey and a healthier, happier you.

Varieties of Intermittent Fasting

The versatility of Intermittent Fasting makes it a suitable option for a wide range of individuals. Among the popular methods are the 16/8, 14/10, and 5:2 approaches, as mentioned earlier. Each method has its unique set of benefits and challenges, making it crucial to select the one that aligns with your lifestyle and health goals. The longer fasting periods of the 16/8 method may offer more pronounced benefits in terms of weight loss and metabolic health, while the 5:2 method provides more flexibility with regular eating days^6.5

Additionally, there’s the Eat Stop Eat method, which involves a 24-hour fast once or twice a week, and the Warrior Diet, which consists of eating small amounts of raw fruits and vegetables during the day and one large meal at night. The variety of options allows for personalization, making Intermittent Fasting an adaptable and practical choice for many. It’s advisable to experiment with different methods and consult with a healthcare professional to find the one that suits you best.

Pros and Cons of Intermittent Fasting

Intermittent Fasting is revered for its ability to promote weight loss, enhance metabolic health, and potentially extend lifespan. The practice can also instill a sense of structure in your eating routine, which can be particularly beneficial for individuals prone to mindless snacking or overeating. Moreover, by reducing the time spent on meal preparation and eating, you may find more time for other meaningful activities in your daily life.

However, it’s not without its drawbacks. Some individuals may find the fasting periods challenging, especially in social or family settings. There’s also the risk of overeating during the eating windows or choosing unhealthy foods that negate the benefits of fasting.6 It’s essential to approach Intermittent Fasting with a balanced perspective, understanding the potential challenges and being prepared to make adjustments to ensure it aligns with your lifestyle and health goals.

Embarking on Your Fasting Journey: A Conclusion

Embarking on the Intermittent Fasting journey is like stepping into a new realm of nutritional consciousness, where the clock takes precedence over the calorie count. It’s a practice rooted in ancestral wisdom, now backed by modern science, offering a gateway to a healthier, more harmonized existence. Whether you’re drawn to the simplicity of the 16/8 method, the flexibility of the 5:2 approach, or the disciplined rigor of the Warrior Diet, there’s a path for everyone in the diverse landscape of Intermittent Fasting. As you venture through the fasting and feasting cycles, may you uncover a lifestyle that resonates with your health aspirations, fostering a mindful eating routine that paves the way for a thriving, vibrant life. Remember, the journey is as significant as the destination; hence, embracing the process, celebrating the small victories, and staying attuned to your body’s signals is the essence of a successful Intermittent Fasting voyage.


  1. Rafael de Cabo, Ph.D., and Mark P. Mattson, Ph.D. “Effects of Intermittent Fasting on Health, Aging, and Disease” N Engl J Med 2019; 381:2541-2551 DOI: 10.1056/NEJMra1905136
  2. Harvie MN, Pegington M, Mattson MP, et al. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. Int J Obes (Lond). 2011;35(5):714-727. doi:10.1038/ijo.2010.171
  3. Harvard Health. “Time to try intermittent fasting?” April 15, 2023
  4. Longo VD, Panda S. Fasting, Circadian Rhythms, and Time-Restricted Feeding in Healthy Lifespan. Cell Metab. 2016 Jun 14;23(6):1048-1059. doi: 10.1016/j.cmet.2016.06.001. PMID: 27304506; PMCID: PMC5388543.
  5. Elortegui Pascual P, Rolands MR, Eldridge AL, Kassis A, Mainardi F, Lê KA, Karagounis LG, Gut P, Varady KA. A meta-analysis comparing the effectiveness of alternate day fasting, the 5:2 diet, and time-restricted eating for weight loss. Obesity (Silver Spring). 2023 Feb;31 Suppl 1(Suppl 1):9-21. doi: 10.1002/oby.23568. Epub 2022 Nov 8. PMID: 36349432; PMCID: PMC10098946.
  6. Sundfør TM, Svendsen M, Tonstad S. Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trialNutr Metab Cardiovasc Dis. 2018;28(7):698-706. doi:10.1016/j.numecd.2018.03.009


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