Fasting is a period we go without food (anything that has calorie) and allow our body to switch from sugar burning phase to fat burning phase. It takes between 8 to 12 hours for the metabolic switch from sugar burning to fat burning state to occur in our body.
The two metabolic states are important in their respective forms: in the feeding state, the body engages in tissue-specific processes of growth and plasticity, while in the fasted state, pathways involved in the repair of damaged molecules and protection against metabolic and oxidative stress are activated by cells1.
However, it’s a matter of concern that majority of modern-day humans don’t experience the healing power of being in the fasted state in their lives due to continuous/regular eating. Majority of us remain in fed/feasting state, with its numerous health implications throughout our lifetime.
The Origin of Intermittent Fasting
Intermittent fasting didn’t start recently. It could be traced back to the days of our ancestors, who had no access to a regular three-meals-a-day regimen, with several snacking periods in-between.
Our ancestors could go without food for hours or even days before eating because they needed to go into the bush to hunt and gather food for themselves. Food and snacks weren’t readily available in the days of our ancestors as they are for us today.
The cavemen weren’t only observing intermittent fasting on a regular basis but were also physically very active with limited comfort when compared to the modern-day lifestyle.
The regular fasting periods and physical activities provided them the opportunity to detoxify and rejuvenate the body from time to time thereby increasing their immunity and overall health.
There were no sophisticated medical facilities in the time of our ancestors, but they lived long in good health without those privileges.
Unfortunately, in our modern and sophisticated world, we eat continuously without break, overloading the body with foods which are often unhealthy (over-processed and sugary), with little or no physical activity.
Our modern sedentary and overeating lifestyle deprive the body the healing powers of fasting.
Health Implications of the Modern–Day Continuous Eating Habits
Being in fed state every hour of the day with no break from food, especially the highly processed and high carbohydrate foods, has numerous health implications which are common in the world today.
No age category (young and old) is spared in the ravaging health damages of modern-day diets and constant eating habit.
These health implications include:
- Insulin resistance
- High blood sugar levels
- Type 2 diabetes
- Overweight/obesity
- Heart diseases (hypertension, high cholesterol, and high triglyceride)
- Low immunity against diseases such as cancer, autoimmune diseases
- Chronic inflammation
- Poor cognitive function
- Neurodegenerative diseases
- Reduced life span
If we understand how body functions when we eat and fast, we will adequately adjust our eating habits and experience the health benefits of the two metabolic states, especially those of the fasting state.
What Happens During the Feeding and Fasting States
Our body uses two forms of energy during the eating and fasting states.
Whenever we eat, the body uses energy in the form of glucose, while in the fasted state, it uses the energy in form of ketones.
So, there’s this constant switch between the two energy sources when we eat and when we fast.
When we eat, our body converts the food into glucose and uses it as a source of energy. Any excess glucose not utilized immediately, is converted into triglycerides in the adipose tissues and stored as fat. So, the larger the meal we eat, the more rapid the excess is stored as fat in adipose tissues2.
If we are eating every 2 to 3 hours, our body will not have sufficient time to utilize every glucose generated from each meal, and so stores the excess as fats.
The fats are what is broken down into ketones which are used as energy when we fast for at least 8 hours in-between meals.
What are Ketones?
These are the end-product of the metabolic break-down of the fatty acids stored in adipose tissues. During fasting, the liver coverts the fatty acids into ketones (β-hydroxybutyrate (BHB), acetoacetate, and acetone) which are distributed to metabolic tissues, especially the brain and muscles.
In fact, it is well reported that ketones are the preferred energy source for the brain. The high cognitive functions (decision making, reasoning, problem solving, learning, attention, thinking) in a fasted state are due to high concentration of ketones in the blood stream which gets to the brain in this state.
Apart from being an alternative energy source to glucose, ketones play a vital role in the proper functioning of the cells in the regulation of diseases and aging3.
Ketones are also produced during a ninety-minute-high intense exercise4.
Some Common Fasting Regimens
- Beginners often start with the 16:8 or 14:10 regimen. That is 16- or 14-hours fasting and 8- or 10-hours eating windows.
- One-meal-a-day (OMAD) is also common.
- Thirty-six hours.
- Forty-eight hours.
These four regimens are the most common fasting periods. However, some people go without food for several days under the guidance of a physician.
The different fasting periods have varying health benefits which we will highlight in another blog post.
What Kinds of Food Can Break Your Fast?
Avoid carbs/sugar/fruits, proteins, some fats, and vegetables, whether natural or artificial, in your fasting window so that you are not knocked off the fat burning phase by the rise in your insulin and glucose level due to these types of food.
In fact, any food that has calorie can break your fast and disrupt the benefits that comes with fasting.
Some foods that you can take in your fasting window without breaking your fast include:
- Water
- Little quantity of medium-chain triglyceride (MCT) oil, extra virgin olive, or other healthy fats (about a tea spoonful).
- Plane coffee and tea (without sugar and cream/milk)
- Dilute apple vinegar.
Summary
The health benefits of fasting cannot be overemphasized. However, there must be a balance between eating and fasting to experience the health benefits of the two states.
If you already have an underlying health challenge, make sure to consult your doctor before embarking on any fasting regimen to avoid complications.
Likewise for healthy individuals who want to go on more than 48 hours fasting period, do that with the consent of your doctor.
Thank you for dropping by. See you in our next post.
References
1. de Cabo R, Mattson MP. Effects of Intermittent Fasting on Health, Aging, and Disease. New England Journal of Medicine. 2019;381(26):2541-2551. doi:10.1056/nejmra1905136
2. Cahill GFJ. 6 Starvation in Man. In: Clinics in Endocrinology and Metabolism. Vol 5. ; 1976:397-415. doi:https://doi.org/10.1016/s0300-595x(76)80028-x
3. Newman JC, Verdin E. β-Hydroxybutyrate: A Signaling Metabolite. Annual Reviews of Nutrition. 2017;37:51-76. doi:10.1146/annurev-nutr-071816
4. Koeslag JH, Noakes TD, Sloan AW. Post-Exercise Ketosis. J Physiol. 1980;301:79-90.
Fantastic insights! This article truly underscores the importance of holistic health. Actually Well-researched and inspiring! It’s great to see such valuable information shared.
It also provides practical tips for a healthier lifestyle.
Thank you for sharing these invaluable health tips.
Thank you so much, Odinaka, for dropping by and your sincere review.
We hope to see you in our next post.