Burn Fat Fast with Intermittent Fasting

By Dr. Mercola.


  • Intermittent fasting or compression of your eating window time, is a powerful approach that facilitates weight loss and helps reduce your risk of chronic diseases like Type 2 diabetes, heart disease and cancer
  • Intermittent fasting covers a variety of different meal timing schedules, but generally speaking involves cutting calories in whole or in part, either a couple of days a week, every other day or daily
  • When you eat throughout the day and never or rarely skip a meal, your body adapts to burning sugar as its primary fuel, which downregulates enzymes that utilize and burn stored fat
  • Research confirms that fasting can effectively reverse Type 2 diabetes in a relatively short amount of time. Fasting has also been shown to trigger the regeneration of the pancreas in both Type 1 and Type 2 diabetics
  • If you’re new to the concept of intermittent fasting, consider starting by skipping breakfast; eat lunch and dinner within an eight-hour timeframe, and make sure you stop eating three hours before you go to sleep

Intermittent fasting is a powerful approach that facilitates weight loss and helps reduce your risk of chronic diseases like Type 2 diabetes, heart disease and cancer. Research overwhelmingly supports the notion that ditching the “three square meals a day” approach in favor of intermittent fasting can do wonders for your health, as your body simply isn’t designed to be continuously fed.

Research by Dr. Satchidananda Panda suggests 90 percent of people eat across a span of 12 hours a day, and many across even longer timespans. Sadly, this is a prescription for metabolic disaster and will clearly wreak havoc with your metabolism over time.

Intermittent fasting typically refers to not eating for at least 14 consecutive hours a day. However, not eating for 16 to 18 hours is likely closer to metabolic ideal. This means you are only eating your food within a six to eight-hour window.

Why Intermittently Fast?

The cycling of feasting (feeding) and famine (fasting) mimics the eating habits of our ancestors and restores your body to a more natural state that allows a whole host of biochemical benefits to occur. In recent years, it’s become increasingly clear that your body cannot run optimally when there’s a continuous supply of calories coming in.

For starters, when you eat throughout the day and never skip a meal, your body adapts to burning sugar as its primary fuel, which downregulates enzymes that utilize and burn stored fat. As a result, you start becoming progressively more insulin resistant and start gaining weight, and most efforts to lose weight become ineffective.

It’s important to realize that in order to lose body fat, your body must first be able to actually burn fat. Two powerful ways of shifting your body from carb-burning to fat-burning are fasting and/or eating a cyclical ketogenic diet. For optimal results, you’d want to do both,1,2 as these strategies support each other, allowing for speedier results. To learn more about this, see “Why Intermittent Fasting Is More Effective Combined With Ketogenic Diet.”

Importantly, many biological repair and rejuvenation processes also take place while you’re fasting, and this is a primary reason why all-day grazing triggers disease while fasting prevents them.

The Many Health Benefits of Intermittent Fasting

A large and growing body of medical research supports the use of intermittent fasting, showing it has a wide range of biological benefits. For example, intermittent fasting has been shown to:3,4,5

1. Promote insulin sensitivity, which is crucial for your health, as insulin resistance or poor insulin sensitivity contributes to nearly all chronic diseases
2. Promote leptin sensitivity
3. Normalize ghrelin levels, also known as the “hunger hormone,” resulting in lowered hunger
4. Improve blood sugar management by increasing insulin-mediated glucose uptake rates6
5. Lower triglyceride levels
6. Increase human growth hormone production (HGH) — Commonly referred to as “the fitness hormone,” HGH plays an important role in maintaining health, fitness and longevity, including promotion of muscle growth, and boosting fat loss by revving up your metabolism. Research7shows fasting can raise HGH by as much as 1,300 percent in women and 2,000 percent in men.

The fact that it helps build muscle while simultaneously promoting fat loss explains why HGH helps you lose weight without sacrificing muscle mass, and why even athletes can benefit from intermittent fasting

7. Suppress inflammation and reduce oxidative damage8
8. Upregulate autophagy and mitophagy, natural cleansing processes necessary for optimal cellular renewal and function
9. Boost fat burning and improve metabolic efficiency and body composition, including significant reductions in visceral fat and body weight in obese individuals
10. Prevent or reverse Type 2 diabetes, as well as slow its progression
11. Improve immune function9
12. Lower blood pressure
13. Reduce your risk of heart disease10 — One study11 found those who fasted regularly had a 58 percent lower risk of coronary disease compared to those who never fasted
14. Reproduce some of the cardiovascular benefits associated with physical exercise
15. Boost mitochondrial energy efficiency and biosynthesis
16. Shift stem cells from a dormant state to a state of self-renewal
17. Reduce your risk of cancer
18. Increase longevity — There are a number of mechanisms contributing to this effect. Normalizing insulin sensitivity is a major one, but fasting also inhibits the mTOR pathway, which plays an important part in driving the aging process
19. Regenerate the pancreas12 and improve pancreatic function
20. Improve cognitive function, thanks to rising ketone levels
21. Protect against neurological diseases such as dementia, Alzheimer’s disease13 and Parkinson’s disease,14,15 thanks to the production of ketone bodies (byproducts of fatty acid breakdown, which are a healthy and preferred fuel for your brain) and brain-derived neurotrophic factor (BDNF, which activates brain stem cells to convert into new neurons, and triggers numerous other chemicals that promote neural health)
22. Eliminate sugar cravings as your body adapts to burning fat instead of sugar

Note: These benefits are not listed in order of importance.

Intermittent Fasting Considerations

While intermittent fasting is likely to be beneficial for most people, here are some points to consider:

Intermittent fasting does not have to be a form of calorie restriction — It’s a practice that should make you feel good. If your fasting strategy is making you feel weak and lethargic, you need to reevaluate your approach.

Sugar cravings are temporary — Your hunger and craving for sugar will slowly dissipate as your body starts burning fat as its primary fuel. Once your body has successfully shifted into fat burning mode, it will be easier for you to fast for as long as 18 hours and still feel satiated.

It is not advisable to practice intermittent fasting if your daily diet is filled with processed foods — While intermittent fasting may sound like a panacea against ill health and excess weight, it alone may not provide you with all of these benefits. The quality of your diet plays an important role if you’re looking for more than mere weight loss.

It’s critical to avoid refined carbohydrates, sugar/fructose and grains. Focus your diet on vegetable carbohydrates, healthy protein in moderate amounts, and healthy fats such as butter, eggs, avocado, coconut oil, olive oil and raw nuts.

Considerations to Take Into Account Before Embarking on Longer Fasts

One of the reasons I’ve reverted back to advising caution with water-only fasting is because multiday water fasting is very effective at liberating stored toxins from your fat, which can cause problems if your detoxification system isn’t properly supported.

While I’ve done several five-day water-only fasts in the past, I’ve now switched to a partial fast that supplies many of the nutrients your body needs to support your detox pathways instead. It involves a base of intermittent fasting for 16 to 18 hours, and once or twice a week you have a 300- to 800-calorie meal loaded with detox supporting nutrients, followed by a 24-hour fast. So, in essence, you’re then only eating one 300- to 800-calorie meal in 42 hours.

Using an infrared sauna and taking effective binders, like chlorella, modified citrus pectin, cilantro and even activated charcoal can help eliminate liberated toxins from your body and prevent their reabsorption. Gradually easing into longer fasts will also help minimize most side effects associated with fasting, as will transitioning over to a high-fat, low-carb diet, to help your body to adjust to using fat as a primary fuel.

The so-called “keto flu” is often related to sodium deficiency, so it’s recommended to take a high-quality unprocessed salt each day. This will also help reduce the likelihood of headaches and/or intractable muscle cramps at night. Another important mineral is magnesium. It’s particularly important if you are diabetic, as magnesium deficiency is very common among Type 2 diabetics.

If you are taking medication, especially for your blood sugar, you have to make sure you talk to your doctor, because there’s a risk your blood sugar may end up dipping too low. If you’re taking insulin, and keep taking insulin while fasting, you could also get yourself into trouble.

If your doctor is adverse toward or unfamiliar with fasting, you’d be wise to find one that has some experience in this area so they can guide you on how to do this safely. There are also several absolute contraindications to water-only fasting. If any of the following apply to you, you should not do extended types of fasting:

  • Underweight, defined as having a body mass index (BMI) of 18.5 or less.
  • Malnourished (in which case you need to eat healthier, more nutritious food).
  • Children should not fast for longer than 24 hours, as they need nutrients for continued growth. If your child needs to lose weight, a far safer and more appropriate approach is to cut out refined sugars and grains. Fasting is risky for children as it cuts out ALL nutrients, including those they need a steady supply of.
  • Pregnant and/or breastfeeding women. The mother needs a steady supply of nutrients in order to assure the baby’s healthy growth and development, so fasting during pregnancy or while breastfeeding is simply too risky for the child.

Take Control of Your Health With Intermittent Fasting

Historically, generous amounts of food were not accessible throughout the entire year, let alone 24/7, and evidence shows you will radically increase your risk for chronic degenerative disease if you’re keeping your body continuously fed. As noted in the paper “A Time to Fast,” published in the November 2018 issue of Science:16

“Adjustment of meal size and frequency have emerged as powerful tools to ameliorate and postpone the onset of disease and delay aging, whereas periods of fasting, with or without energy intake, can have profound health benefits.

The underlying physiological processes involve periodic shifts of metabolic fuel sources, promotion of repair mechanisms, and the optimization of energy utilization for cellular and organismal health.

Future research endeavors should be directed to the integration of a balanced nutritious diet with controlled meal size and patterns and periods of fasting to develop better strategies to prevent, postpone and treat the socioeconomical burden of chronic diseases associated with aging …

In general, both prolonged reduction in daily caloric intake and periodic fasting cycles have the power to delay the onset of disease and increase longevity.”

If you’re new to the concept of intermittent fasting, consider starting by skipping breakfast; eat lunch and dinner within an eight-hour time frame, and make sure you stop eating three hours before you go to sleep.

The latter is important, as it helps protect your mitochondrial function. Recent research17 shows men who eat supper at least two hours before bedtime have a 26 percent lower risk of prostate cancer, and women have a 16 percent lower risk of breast cancer than those who eat dinner closer to bedtime. For more details on why this is so, see “Eating Early Dinner Aids Weight Loss and Lowers Cancer Risk.”

When you do eat, focus on healthy protein in moderate amounts, minimize net carbs like pasta and bread, exchanging them for healthy fats like butter, eggs, avocado, coconut oil, olive oil and raw nuts.

This will help shift you into fat burning mode. Remember, it may take a few weeks, but once you succeed, you may be easily able to fast for 18 hours and not feel hungry, making it that much easier to achieve your ideal weight. Virtually every aspect of your health will also begin to improve.