Go Deep

Intermittent Fasting


minute read

April 15, 2018

Learn about this growing wellness trend & find out if It can work for you.

Intermittent fasting

Become familiar with Intermittent Fasting - the process, it’s benefits, effectiveness and similar concepts shared with the keto diet.

Fasting is one of the oldest healing traditions in human history. It was practiced by almost every culture or religion and has many proven health benefits. Fasting is defined as the absence of food for a longer period of time. It can be involuntary, which was the case when our ancestors were hunters and gatherers and couldn’t eat every day.  It can also be voluntary by intentionally withholding food for health, spiritual or other reasons. Fasting is rather a natural eating pattern, to which our bodies adapted over thousands of years. In fact, our ancestors could withstand longer periods without food and still be able to pursue high intensity physical activities like hunting and running from danger. Evolutionary theory would therefore suggest that our bodies are not meant to eat 3-4 meals a day, because our bodies got adapted over millions of years to longer fasting periods.

What is Intermittent Fasting?

Intermittent fasting (IF) is less of a diet, but rather an eating pattern, where you control the time when you eat and the time when you fast. IF doesn’t define what food to eat but provides different methods to simulate short or longer fasting periods. It has caught a lot of attention recently, because some scientific studies indicate significant health benefits and IF eating patterns are easier to execute than specific diets.

How IF Affects the Body

Fasting is a critical parameter which affects our metabolism and triggers many processes on a cellular and molecular level. From a high-level perspective, fasting induces a katabolic state in cells, which triggers hormones, repair processes and also changes the expression of genes.

Here are the main processes we observe during fasting – it is very likely that these processes and mechanisms are interrelated:

  • Increase of human growth hormone (HGH) production: During a fasting period, the production of HGH increases up to 400% and these increased levels lead to muscle growth and fat loss.
  • Reduction of insulin response: Due to the reduction or lack of glucose in the blood during a fast, the levels of insulin decease which improves insulin sensitivity and reduces cravings. Due to reduced insulin, the fat storage process is restricted as well, which can result in weight loss.
  • Autophagy (cellular recycling): Autophagy is a natural destructive mechanism of the cell that allows degradation and recycling of cellular components. When fasting puts the cells in a katabolic state, they induce autophagy, where they recycle re-usable proteins and remove disfunctional or damaged cell components (find a more detailed explanation here).
  • Production of ketones: After the glycogen levels are depleted during a fast, the liver will start to process stored fat and produce ketones. This can result in a mild state of ketosis with an increased ketone blood concentration (>0.5 mmol/l).
  • Reduction of inflammation and oxidative stress: Several studies point out, that inflammation levels are being reduced significantly during a fast. The reason is not well understood. One hypothesis states that because of a reaction of the immune system resulting from a damaged gut wall or leaky gut, body inflammation levels are increased significantly. Fasting can help to improve your gut microbiome and even help to heal a leaky gut and therefore reduce inflammation.

Health Benefits of IF

Based on the processes described above, IF has several health benefits:

  • ‍Improved mental clarity and increased energy
  • Increased fat burning and weight loss
  • Reduced risk of Type 2 Diabetes
  • Improved heart health, lowered blood cholesterol and risk of cardiovascular disease
  • Anti-aging potential and longer life
  • Cancer reversal and prevention
  • Improved brain health and lowered risk of neurodegenerative diseases (eg. Alzheimer)
  • Healing of gut
  • Decreased hunger
  • Strengthening of immune system
  • Improved skin

Different IF methods

These are the most popular methods for IF that you can try:

The 16:8 Method (Leangains protocol):

With this method, you can eat during a period of 8 hours per day and restrict food during the remaining 16 hours. Most people find it easiest to skip breakfast and eat 2-3 meals between noon and 8pm. The 16:8 method doesn’t restrict any calories and depending on your weight target, you can eat the same number of calories as usual, just within a restricted period.


This method involves a 24 hour fast once or twice a week. During the fasting period, you should drink calorie-free beverages like water or unsweetened tea to stay hydrated and you should supplement with sea salt and other electrolytes to avoid headaches or fatigue. You can break the fast with a large meal or just with a small snack, whatever makes you feel better. If you want to boost weight-loss and improve your body composition, you can work out during the fasting period.

1-Meal-A-Day (Warrior Diet):

The 1-meal-a-day diet is very popular due to its effectiveness, but difficult to execute for most people, due to the 20 hour+ fasting periods. The meal is mostly consumed in the late afternoon or evening, because you will fall asleep easier on a full stomach. You do not have to restrict calories on this diet, but because it is difficult to eat 1 meal of 2,000-2,500 kcal at once, you usually restrict calories by 20-25% with this method. Due to the long and regular (daily) fasting periods and mild calorie restriction, the health benefits described above are most prominent in this method.

5:2 Method:

We do not consider the 5:2 Method a real intermittent fasting method, because it’s more a calorie restriction method without a clear eating pattern. With the 5:2 Method, you eat regularly during 5 days per week and on 2 non-consecutive days you restrict your calories to 500- 700 kcal.

Side Effects and Risks of IF

  • Cravings - When you start your IF routine, your body expects food at the times you regularly had your meals in the past. So, when you omit these meals the body will react to it with hunger and cravings. These cravings will vanish after the body is adjusted to the new eating pattern after about 2-3 weeks.
  • Headaches - Due to the reduction of stored water in your body, you also flush-out important minerals, such as sodium, potassium, magnesium and calcium. Make sure to drink sufficient water and add a tablespoon of sea salt. You can also take supplements to counter this effect.
  • Low Energy - Having low energy can have several reasons. One may be the lack of minerals mentioned above. Another reason could be that the body is not well adapted to burning fat as fuel. Therefore, we recommend a 3-week keto-adaption program before you start IF to make sure that your body can run efficiently on fats.
  • Irritability - Everyone knows that if people are hungry, they are usually in a very bad mood and short tempered. If keto adapted, the body will cycle into mild ketosis (>0.5 mmol/l) during the fasting period and with increasing blood ketone concentration the body starts to regulate hunger-related hormones, which suppress the feeling of hunger and reduce irritability. This is just another reason to wait until you are fully keto-adapted before you begin a IF regimen.
  • Overeating - When people start IF, a powerful psychological process takes place, where you feel that something is being taken away from you.  This feeling is regularly overcompensated with overeating during the eating periods.  This is something to be aware of and monitor to the best of your ability.
  • Heartburn, Bloating & Constipation - Overeating and the adaption of the metabolism can cause digestive issues in the short term. To avoid this, you should eat whole and fresh foods and omit processed foods as a general rule.

If you have any medical conditions, you should consult with your doctor before trying IF. Following conditions or situations require particular caution:

  • ‍Diabetes
  • Problems with blood sugar regulation
  • Low blood pressure
  • Take medications
  • If you are underweight
  • History of eating disorders
  • If you are trying to conceive
  • If you are pregnant or breastfeeding

Overall IF is considered to be a very safe eating pattern and there is nothing dangerous about IF, if you eat healthy.