There are many different types of fasts, but the most popular and practical is called intermittent fasting. Intermittent fasting gives your body more time to effectively digest what you are eating and eliminate waste.
The most popular way to do intermittent fasting is to restrict your daily food intake to a specific window of time - typically a six to eight-hour time-frame each day.
For example, if you skip breakfast and make lunch the first meal of your day, you might restrict your food intake to the hours of 11:00 a.m. and 7:00 p.m. If you are a breakfast lover, your window could be between 8:00 a.m. and 4:00 p.m. The best results are obtained by having an early feeding window to match the bodies circadian rhythm. Food intake is a major part of setting that rhythm along with morning bright light exposure and limiting light for 2 - 3 hours before bed.
If you choose a later feeding window make sure you stop eating or drinking anything with calories at least three hours before bedtime. This ensures that you get a better growth hormone release during sleep and avoid heartburn. When you eat three or more meals a day, you rarely, if ever, empty your glycogen stores (storage form of glucose – mostly in your liver), mainly because it takes about eight to 12 hours to burn the sugar stored in your body as glycogen.
By fasting about 16 to 18 hours a day, you give your body enough time to drain your glycogen stores and shift into fat-burning mode. This pushes your body to use fat as a fuel. Because fat is a slow-burning fuel, you will not only have a more balanced energy supply, but you will also avoid the typical sugar "highs" and "lows" that come with typical diets.
While you will undoubtedly feel hungry on occasion, that is perfectly normal. Once your body adjusts, you may be surprised to discover how much less food you will consume to feel completely satisfied. In many cases your food cravings literally disappear once you have regained your ability to burn fat for fuel.
Benefits of Intermittent Fasting
Intermittent fasting provides a number of health benefits including:
- Forces the body to become efficient at burning fat as the primary fuel which helps eliminate sugar cravings
- Increases growth hormone to help build muscle and promote overall health and wellness
- Enhances brain health and helps prevent neurological disorders like Alzheimer's
- Reduces oxidative stress and fights aging and diseases like cancer
- Lowers triglycerides and reduces inflammation
- Dramatically boosts brain derived neurotrophic factor (BDNF) which activates brain stem cells to convert into new neurons.
- Dramatically increases the process of Autophagy
Benefits of Autophagy
During the bio-energetic challenge of exercising or fasting, autophagy is increased. This stimulates stem-cells including muscle stem cells which can help prevent sarcopenia (muscle loss with aging). So, intermittent fasting can help maintain the regenerative capacity of muscle stem cells.
There are three ways to boost autophagy: exercise, fasting, and nutritional ketosis.
Difference between intermittent fasting and chronic low calorie intake (aka dieting!)
There is a huge difference in what happens when we intermittent fast compared to eating low calorie all the time. When we keep our daily calories low for weeks or months at a time our body compensates by slowing our metabolic rate aka our daily calorie burn. In addition you end up losing lean mass (muscle) which is exactly what we you want to avoid as you get older! You also end up feeling deprived, fatigued, and it is easy to not fulfill all your nutrient needs.
Intermittent fasting does NOT reduce metabolic rate or result in loss of lean mass because of the cyclical nature of the practice. Since calories are not chronically reduced the body does not slow down. You can use this method for weight loss but it is easy to maintain your weight by simply eating enough during your eating window each day.
How to get started with Intermittent Fasting
There is no need to jump right into a 16 - 18 daily fast. Start by not eating in an eight hour window then progress slowly to 10 hours then 12 and eventually 16-18 hours. A good plan is doing a week at 8 - 10 hours of fasting then progress to 10 - 12 hours the following week then 12 - 14 hours the third week and finally 16 - 18 hours in the fourth week. This is very easy and not a big shock for most people.
The Importance of Proper Food Choices during Intermittent Fasting
During intermittent fasting, your food choices are very important. Since you'll be eating less, it's vitally important that you get proper nutrition from your food. Healthy fats are essential because intermittent fasting pushes your body to switch over to fat-burning. Particularly if you begin to feel tired and sluggish, it may be a sign that you need to increase the amount of healthy fat in your diet.
Cutting net carbs (total carbs minus fiber) is equally important. Focus on:
- High quality fat intake in the form of avocados, coconut oil, organic grass-fed butter, organic egg yolks and nuts.
- Moderate amounts of high-quality protein from organically raised, grass-fed or pastured animals, which translates to no more than 40 to 80 grams of protein per day
- High amounts of fresh, low-net-carb vegetables, ideally organic
Contraindications for Fasting
Although most people can safely benefit from intermittent fasting, it's important to take caution if you have certain health challenges. Do NOT use fasting unless approved by your physician if any of the following are true:
- You are underweight with a body mass index (BMI) of 18.5 or less
- You are malnourished
- Children should NOT fast! They need nutrients for continued growth; if your child is obese, consider cutting him or her back on refined grains and sugar to promote weight loss
- Pregnant and breastfeeding women should NOT fast because a consistent flow of nutrients must be shared continually with the baby to ensure its well-being
- If you take medications that should be taken with food you will need to be very cautious about fasting and consult with your physician first. This is especially true for diabetics and those with gout.