Get Healthy, Permanent Weight Loss Starting Today | Intermittent Fasting Weight Loss Tips

Article written and reviewed by Cyrus Khambatta, PhD
Published July 30, 2023

Intermittent fasting is one of the most powerful strategies for improving your overall metabolic health, not just for weight loss, but for your overall health, with benefits ranging from reduced risk of heart and cardiovascular disease to reduced insulin resistance and significantly improved diabetes health

But there’s a lot of information about intermittent fasting, and not all of it is scientifically accurate or even helpful. Fasting is POWERFUL, but there’s a distinct difference between SMART fasting and EXTREME fasting (or outright starving yourself!) so we want to make sure you’re heading in the right direction.

So in this blog we’re going to take a few moments to go over what intermittent fasting is (in case you’re new to this topic), and if you’re part of a small population of people who might want to be more careful or avoid fasting

Then we’re going to get into the nuts and bolts, including:

  • how to start intermittent fasting

  • our recommended fasting schedules for weight loss and reduced chronic disease risk

  • what you can eat or drink during your fasting period and 

  • some tips for crushing your intermittent fasting strategy

Quick Hits | What We Know About Intermittent Fasting

Think back to gatherer-hunter time when humans didn’t have access to 3 meals a day PLUS snacks. In truth, our human ancestors were actually gatherer-hunters, given that they spent the majority of their time gathering and a minority of their time hunting. 

In order to survive long periods of limited food availability, our human ancestors often fasted for extended periods of time, sometimes up to ten days in a row.

Autophagy essentially helps your body utilize stored energy sources efficiently, allowing it to sustain and function optimally even during periods of limited food availability. 

This evolutionary adaptation has been crucial for our ancestors' survival and continues to play a significant role in our metabolic health today.

This pattern of fasting and feasting—cycling between periods of high and low calorie intake—created a series of biochemical adaptations that naturally selected for those who could survive an uncertain food supply. 

Scientists believe that over time, metabolic adaptations allowing for regular intermittent fasting became ingrained in the genetic material of modern humans. 

As a result, modern-day humans are not only capable of fasting for extended periods but actually derive substantial metabolic benefits from fasting.

So, imagine a scenario where you didn't eat breakfast, but you still needed to hunt, raise kids, find food, and survive in general. Your body would activate a sort of internal recycling program known as autophagy. 

This biological mechanism is conserved, meaning humans have evolved with this mechanism over millions of years. Autophagy involves the oxidation of fatty acids that have been stored for a long period of time, along with stored carbohydrates in your muscles and liver. 

Autophagy essentially helps your body utilize stored energy sources efficiently, allowing it to sustain and function optimally even during periods of limited food availability.

This evolutionary adaptation has been crucial for our ancestors' survival and continues to play a significant role in our metabolic health today.

Live “Fast”, Live Long | Calorie Restriction Increases Longevity

The concept of calorie restriction (CR) dates back to the 1930s when Clive McCay and his colleagues made a groundbreaking discovery. 

They found that laboratory rats given restricted calorie intake lived longer compared to their counterparts who had unrestricted access to food around the clock.

This single observation sparked a surge of scientific research aimed at unraveling the underlying biological mechanisms responsible for reducing the rate of aging, increasing longevity, enhancing memory, and promoting weight loss. 

Additionally, calorie restriction was found to reduce the risk of chronic metabolic conditions such as heart disease, cancer, and type 2 diabetes.

Remarkably, calorie restriction has been shown to be effective across a wide range of organisms studied thus far, including yeast, worms, flies, mice, rats, and more recently, monkeys. 

It consistently demonstrates its ability to increase lifespan and delay the onset of various age-related diseases.

In fact, calorie restriction is the only known mechanism that has been scientifically proven to extend longevity.

The evidence is compelling. Studies have shown that a reduction in calorie intake by 20 to 50 percent can increase lifespan by up to 50 percent and prevent or delay the onset of numerous chronic diseases, including obesity, type 2 diabetes, cancer, nephropathy, cardiomyopathy, neurodegeneration, and multiple autoimmune diseases.

Inducing calorie restriction is an undeniably powerful approach to improve various aspects of metabolic health simultaneously. By adopting a mindful approach to our calorie intake, we have the potential to positively influence our longevity and reduce the risk of age-related diseases, leading to a healthier and more vibrant life.

Fast-Track to Health | Health Benefits of Intermittent Fasting

While calorie restriction on the scale of those studies is undoubtedly powerful, it can be challenging to accomplish. However, shifting our perspective can make it more manageable. 

Instead of focusing on full CR, let's emphasize the concept of negative calorie balance (NCB), which refers to a metabolic state where your energy expenditure exceeds energy intake.

Think of it as managing a checking account. By operating in negative calorie balance for extended periods, our muscles and liver are compelled to oxidize stored glucose and fatty acids, making them more responsive to these fuels when they are available again. This process has significant benefits for our health.

There are two primary reasons why this is important. 

Firstly, the oxidation of excess stored fat within our muscles and liver enhances their ability to communicate effectively with insulin (which is insulin resistance, a topic we discuss a lot both here and in our book). 

Reducing fat content unlocks the insulin receptor's potential to recognize and interact with insulin more efficiently.

Secondly, negative calorie balance not only oxidizes fat but also targets glucose stored in the form of glycogen. As the glycogen storage tank decreases in size, muscle and liver cells activate intracellular mechanisms that facilitate the import of glucose when it becomes available again. 

In essence, negative calorie balance triggers the activation of key enzymes in muscle and liver cells, creating a state of cellular "hunger."

It may seem counterintuitive, but scientific studies have revealed that reducing food intake for extended periods allows blood vessels throughout the body to relax, leading to a reduction in blood pressure. 

Calorie restriction has been shown to improve the function of endothelial cells that line the inside of blood vessels. This enhancement enables them to produce nitric oxide (NO), a gas that promotes blood vessel dilation.

Run Fast or Just Fast? Comparing Exercise to Calorie Restriction

In addition to its impact on nitric oxide (NO) synthesis, calorie restriction has been found to have substantial effects on lipid profiles. 

Studies demonstrate that calorie restriction leads to significant reductions in LDL cholesterol and triglyceride levels, while directly improving the function of the heart muscle. 

Surprisingly, calorie restriction has been shown to be as effective as exercise in achieving these benefits, as evidenced by a study highlighted below.

However, the benefits of calorie restriction extend beyond heart disease. Research conducted at UC Berkeley revealed that negative calorie balance reduces the global cell proliferation rate. This means that cells in all tissues decrease their replication speed, which subsequently lowers the rate of tumor cell formation.

Given that being overweight significantly increases the risk of developing many types of cancers by elevating the global cell proliferation rate, weight loss resulting from negative calorie balance emerges as one of the most potent approaches for preventing and reversing various chronic diseases, including cancer.

Don’t False-Start | Who Shouldn’t Try Intermittent Fasting?

When it comes to intermittent fasting, the risks and side effects are minimal, considering that this process is inherently embedded in our DNA. However, there are certain individuals who should exercise caution or avoid intermittent fasting altogether.

Those who should not engage in fasting include young children, pregnant women, and breastfeeding mothers. These groups have specific nutritional needs that require consistent and regular intake of calories and nutrients.

Additionally, individuals with type 1 diabetes should limit fasting periods to a maximum of 24 hours and closely monitor their blood glucose levels to avoid any complications. People with eating disorders, athletes aiming to gain muscle mass for competitions, and individuals who are underweight should also approach intermittent fasting with caution, as it may not align with their specific health goals or needs.

If you have a medical condition or take medication, practicing intermittent fasting may present challenges and require careful consideration. It is advisable to have a discussion with your healthcare provider to determine the suitability of intermittent fasting for your individual circumstances.

For the majority of individuals, the risks and side effects of intermittent fasting are minimal. Some common experiences in the initial stages may include increased hunger, feelings of fatigue, and lightheadedness as the body adjusts to the new eating schedule. However, these effects typically subside within a week or so.

It is essential not to overthink or scare yourself into sitting on the sidelines if you think that intermittent fasting may help with your health goals. Instead, approach intermittent fasting with an open mind and make gradual adjustments until you find a comfortable routine that works for you.

Sprint or a Marathon| How Do I Start, and How Long Should I Go?

When it comes to intermittent fasting, there are several strategies that you can employ to make it work for you. Let's explore some of the popular approaches:

The Once Per Week 24-Hour Fast: This strategy involves fasting for a full 24 hours once per week. During this period, you consume only calorie-free fluids, such as water, herbal tea, or black coffee. This approach allows for a reset and provides the body with a regular period of extended fasting.

The Twice Per Week 24-Hour Fast: Similar to the once-per-week approach, this strategy involves fasting for a full 24 hours, but it is done twice per week. For example, you may choose to fast on Mondays and Thursdays. Again, during the fasting period, you consume only calorie-free fluids.

The Daily 16:8 Intermittent Fasting Strategy: This approach involves restricting your eating window to 8 hours and fasting for the remaining 16 hours each day. For instance, you might choose to eat between 12:00 PM and 8:00 PM and fast for the rest of the day, including overnight. During the fasting period, you can consume calorie-free beverages.

The key is to find a fasting schedule that aligns with your lifestyle and preferences. Experiment with different approaches and choose one that feels sustainable and manageable for you. Consistency is key, so once you find a schedule that works, stick to it until it becomes automatic and integrated into your daily routine.

As for the duration of intermittent fasting, there is no specific time limit. You can practice intermittent fasting for as long as you desire, even for the rest of your life. Many people find it to be a sustainable long-term approach to maintaining their health and achieving their goals.

Remember, the goal is to find a fasting strategy that suits your needs and preferences, and to practice it consistently. Intermittent fasting can be a flexible and adaptable approach that you can personalize to fit your lifestyle and enjoy the numerous benefits it offers.

16 Hours Seems Like a While | Can I Eat Anything During My Fast?

As you embark on your intermittent fasting journey, you may wonder what you can consume during your fasting period. While the primary goal is to abstain from food, there are some options that you can include without breaking your fast.

First and foremost, it's important to note that including your sleep time in the fasting period can help reduce the overall time you'll be eating, extending the duration of your fasted state. This is particularly beneficial as it allows for the activation of autophagy, the cellular recycling program that offers various health benefits. 

This is why the 16:8 strategy mostly comprises sleep time. 

And while it's crucial to avoid substantial calorie consumption during your fasting period, certain beverages and low-calorie foods can be consumed without disrupting the fasting state. Here are some options:

  • Water: Staying hydrated is essential during fasting periods, so drinking water is encouraged.

  • Coffee and Tea: Black coffee and unsweetened tea, such as green tea, can be consumed without adding calories. Amla Green Tea, in particular, is known for its high antioxidant content and metabolic benefits.

  • Non-Starchy Vegetables: Snacking on non-starchy vegetables like cauliflower, broccoli, cucumbers, or tomatoes can be a way to satisfy hunger while keeping your calorie intake minimal.

It's important to remember that consuming even as little as 100 calories can disrupt the fasting state and shift your body into a fed state. To fully reap the benefits of intermittent fasting, it's best to avoid caloric intake during the fasting period.

And when it comes to enhancing your intermittent fasting experience, we highly recommend incorporating Amla Green Tea or other high-antioxidant teas into your routine. Not only do these teas have zero calories, but they also have the potential to double the effects of your fasting efforts.

Amla, also known as Indian gooseberry, is a superfood that offers numerous metabolic benefits. It is packed with antioxidants, including vitamin C, which can support your overall health and well-being. Amla has been traditionally used in Ayurvedic medicine for its various medicinal properties, including its potential to boost metabolism and aid in digestion.

As a special offer for Mastering Diabetes fans like you, we're extending a 20% discount on our Amla Green Tea or other selected products. Simply use the code MASTERINGDIABETES20 at checkout to take advantage of this exclusive offer.

What Happens If I Get SUPER Hungry?

If you find yourself feeling exceptionally hungry during your fast, there are strategies to help manage the discomfort. Take a moment to pause, take deep breaths, and distract yourself from thoughts of food. 

Going outside for a walk or engaging in a different activity can also help shift your focus away from hunger. It's important to distance yourself from food sources and create an environment that supports your fasting goals.

Ultimately, intermittent fasting requires commitment and discipline to refrain from eating during the designated fasting period. By following these tips and staying motivated, you can have a successful and satisfying intermittent fasting experience.

Fasting and Fast Foods?? | What Can I Eat During My Eating Window?

When it comes to deciding what to eat during your eating window, it's important to approach this question with a focus on overall health and aligning with your goals. While technically you can eat anything you want, we highly recommend adopting a low-fat, plant-based, whole-food diet. 

Yes, it's our favorite diet to recommend, and for good reason.

A low-fat, plant-based, whole-food diet is not only in line with your weight loss goals, but it also promotes improved immune health, reduces the risk of heart disease, and helps manage diabetes effectively. 

On the other hand, diets high in meat, fat, and processed foods can increase your risk of heart disease, lead to weight gain, compromise your immune health, and contribute to insulin resistance.

By following a low-fat, plant-based, whole-food diet, you're not only supporting your fasting efforts but also nourishing your body with nutrient-dense, fiber-rich foods that provide a wide range of health benefits. To give you an idea of our recommendations, here's a breakdown based on the Mastering Diabetes method:

By focusing on a low-fat, plant-based, whole-food diet during your eating window, you'll not only enhance the benefits of intermittent fasting but also improve your overall health and well-being.

Will Fasting Make Me Slower? | Energy and Physical Fitness Under Fasting

A common concern among individuals considering fasting is whether it will make them weaker, especially if they're following a low-fat, plant-based, whole-food diet. However, the notion that you need to consume excessive amounts of protein to maintain strength is highly exaggerated. 

Many plant-based athletes, like myself, thrive on a well-balanced, plant-powered diet.

One of the questions that often arises is whether fasting will hinder your ability to exercise. While the first week of fasting may be challenging as your body adjusts, rest assured that you'll be able to exercise effectively. 

In fact, beyond the initial adjustment period, fasting can actually enhance the effectiveness of your workouts. As your body adapts to burning fat for fuel, you can still engage in muscle growth while experiencing the benefits of fasting. It's important to note that after approximately three days, your hunger levels will typically decrease.

If you're performing high-intensity exercises, it's recommended to schedule your workouts during your eating window. This ensures that you have the necessary energy and nutrients to support your physical activity.

Another concern often raised is whether intermittent fasting will lead to muscle loss. While it's true that weight loss can result in the loss of about one-third muscle mass and two-thirds fat, exercise plays a crucial role in preserving muscle mass when calorie-restricted. 

By incorporating regular exercise into your routine, you can minimize muscle loss and support overall strength and fitness.

Remember, fasting can be a powerful tool for improving your metabolic health and achieving your goals. With proper guidance and a balanced approach, you can maintain your physical fitness and enjoy the benefits of intermittent fasting.

Tips for Beginners to Get Started Intermittent Fasting

If you're new to intermittent fasting, here are 11 tips to help you get started and make the most of this approach:

  1. Start slowly: Begin with a shorter fasting window and gradually increase it over time as you become more comfortable with the fasting period.

  2. Stay hydrated: Drink plenty of water throughout the day, particularly during your fasting period, to stay hydrated and curb feelings of hunger.

  3. Plan your meals: Plan your meals in advance, focusing on whole, nutrient-dense foods during your eating window to support your overall health and well-being.

  4. Be consistent: Establish a consistent fasting schedule that works for you and stick to it to help your body adjust to the new routine.

  5. Listen to your body: If you feel unwell or excessively hungry during your fasting period, it's okay to break your fast early and eat. Pay attention to your body's signals.

  6. Stay busy: Keep yourself engaged and occupied during your fasting period to help distract from hunger and cravings.

  7. Don't overeat: Although intermittent fasting allows for larger meals during your eating window, it's still important to eat until you are satisfied, not overly full.

  8. Eat a nutrient-dense diet: Focus on consuming a low-fat, plant-based, whole-food (LFPBWF) diet, as it provides ample nutrients and aligns with the principles of intermittent fasting.

  9. Stay active: Incorporate regular physical activity into your routine to maximize the benefits of intermittent fasting and support your overall health.

  10. Get enough sleep: Aim for seven to nine hours of quality sleep each night to support your body's natural rhythms and promote well-being.

  11. Consider working with a healthcare professional: If you have any underlying medical conditions or concerns, it may be beneficial to consult with a healthcare professional to determine if intermittent fasting is suitable for you and to receive personalized guidance.

If you're interested in learning more about intermittent fasting or need guidance on any aspect of this method, feel free to reach out to us or book a discovery call. We're here to support you on your journey.

About the author 

Cyrus Khambatta, PhD

Cyrus Khambatta, PhD is a New York Times bestselling co-author of Mastering Diabetes: The Revolutionary Method to Reverse Insulin Resistance Permanently in Type 1, Type 1.5, Type 2, Prediabetes, and Gestational Diabetes.

He is the co-founder of Mastering Diabetes and Amla Green, and is an internationally recognized nutrition and fitness coach who has been living with type 1 diabetes since 2002. He co-created the Mastering Diabetes Method to reverse insulin resistance in all forms of diabetes, and has helped more than 10,000 people improve their metabolic health using low-fat, plant-based, whole-food nutrition, intermittent fasting, and exercise.

Cyrus earned a Bachelor of Science in Mechanical Engineering from Stanford University in 2003, then earned a PhD in Nutritional Biochemistry from the University of California at Berkeley in 2012. He is the co-author of many peer-reviewed scientific publications.

He is the co-host of the annual Mastering Diabetes Online Summit, a featured speaker at the Plant-Based Nutrition and Healthcare Conference (PBNHC), the American College of Lifestyle Medicine Conference (ACLM), Plant Stock, the Torrance Memorial Medical Center, and has been featured on The Doctors, NPR, KQED, Forks Over Knives, Healthline, Fast Company, Diet Fiction, and the wildly popular podcasts the Rich Roll Podcast, Plant Proof, MindBodyGreen, and Nutrition Rounds.

Scientific Publications:

Sarver, Jordan, Cyrus Khambatta, Robby Barbaro, Bhakti Chavan, and David Drozek. “Retrospective Evaluation of an Online Diabetes Health Coaching Program: A Pilot Study.” American Journal of Lifestyle Medicine, October 15, 2019, 1559827619879106. https://doi.org/10.1177/1559827619879106

Shrivastav, Maneesh, William Gibson, Rajendra Shrivastav, Katie Elzea, Cyrus Khambatta, Rohan Sonawane, Joseph A. Sierra, and Robert Vigersky. “Type 2 Diabetes Management in Primary Care: The Role of Retrospective, Professional Continuous Glucose Monitoring.” Diabetes Spectrum: A Publication of the American Diabetes Association 31, no. 3 (August 2018): 279–87. https://doi.org/10.2337/ds17-0024

Thompson, Airlia C. S., Matthew D. Bruss, John C. Price, Cyrus F. Khambatta, William E. Holmes, Marc Colangelo, Marcy Dalidd, et al. “Reduced in Vivo Hepatic Proteome Replacement Rates but Not Cell Proliferation Rates Predict Maximum Lifespan Extension in Mice.” Aging Cell 15, no. 1 (February 2016): 118–27. https://doi.org/10.1111/acel.12414

Roohk, Donald J., Smita Mascharak, Cyrus Khambatta, Ho Leung, Marc Hellerstein, and Charles Harris. “Dexamethasone-Mediated Changes in Adipose Triacylglycerol Metabolism Are Exaggerated, Not Diminished, in the Absence of a Functional GR Dimerization Domain.” Endocrinology 154, no. 4 (April 2013): 1528–39. https://doi.org/10.1210/en.2011-1047

Price, John C., Cyrus F. Khambatta, Kelvin W. Li, Matthew D. Bruss, Mahalakshmi Shankaran, Marcy Dalidd, Nicholas A. Floreani, et al. “The Effect of Long Term Calorie Restriction on in Vivo Hepatic Proteostatis: A Novel Combination of Dynamic and Quantitative Proteomics.” Molecular & Cellular Proteomics: MCP 11, no. 12 (December 2012): 1801–14.

Bruss, Matthew D., Airlia C. S. Thompson, Ishita Aggarwal, Cyrus F. Khambatta, and Marc K. Hellerstein. “The Effects of Physiological Adaptations to Calorie Restriction on Global Cell Proliferation Rates.” American Journal of Physiology. Endocrinology and Metabolism 300, no. 4 (April 2011): E735-745. https://doi.org/10.1152/ajpendo.00661.2010

Bruss, Matthew D., Cyrus F. Khambatta, Maxwell A. Ruby, Ishita Aggarwal, and Marc K. Hellerstein. “Calorie Restriction Increases Fatty Acid Synthesis and Whole Body Fat Oxidation Rates.” American Journal of Physiology. Endocrinology and Metabolism 298, no. 1 (January 2010): E108-116.