Intermittent Fasting: A Beginner's Guide
29/06/2022 | Catarina Vilela - Mipmed
Intermittent fasting (IF) is currently one of the most popular health and fitness trends in the world, aiming to lose weight, improve your health, and simplify lifestyles.
Many studies show that it can have powerful effects on the body and brain and may even help you have greater longevity.
What is Intermittent Fasting?
Intermittent fasting is an eating pattern that alternates between periods of fasting and eating.
It doesn't specify what foods you should eat, but when you should eat them. It's not a diet in the conventional sense, but more accurately described as an eating pattern.
Common methods of intermittent fasting involve 16-hour daily fasts or 24-hour fasting twice a week.
Fasting has been a practice throughout human evolution. Ancient hunter-gatherers didn't have supermarkets, meatpackers, or food available year-round and sometimes couldn't find anything to eat. As a consequence, humans evolved to be able to function without food for long periods of time.
In fact, fasting once in a while is more natural than eating 3 to 4 (or more) meals a day.
Fasting is also often done for religious or spiritual reasons, including in Islam, Christianity, Judaism, and Buddhism.
In short: Intermittent fasting is an eating pattern that alternates between periods of fasting and eating. It is currently very popular in the health and fitness community.
Intermittent fasting methods
There are several different ways to do intermittent fasting – they all involve dividing the day or week into periods of eating and fasting.
During periods of fasting, eat very little or nothing.
These are the most popular methods:
The 16/8 method: Also called the Leangains protocol, involves skipping breakfast and restricting the daily eating period to 8 hours, such as 1pm to 9pm. Then fast for 16 hours in between.
Eat-Stop-Eat: This involves fasting for 24 hours once or twice a week, for example, not eating from dinner one day until dinner the next day.
The 5:2 diet: With this method, you consume only 500-600 calories on two non-consecutive days of the week, but eat normally on the other 5 days.
By reducing calorie intake, these methods cause weight loss, as long as you don't overcompensate by eating a lot more during eating periods.
Many people find the 16/8 method the simplest, most sustainable, and easiest to follow. It is also the most popular.
In short: There are several different ways to do intermittent fasting. They all divide the day or week into periods of eating and fasting.
How does (JI) affect cells and hormones?
When you fast, there are consequences in the body at the cellular and molecular level. For example, adjusting hormone levels to make stored body fat more accessible. Cells initiate important repair processes and alter gene expression.
Some changes that occur in your body when you fast:
Human Growth Hormone (HGH): Growth hormone levels skyrocket, increasing up to 5 times, which is beneficial for fat loss and muscle gain.
Insulin: Insulin sensitivity improves and insulin levels drop dramatically. Lower insulin levels make stored body fat more accessible.
Cell repair: When fasting, cells initiate cell repair processes, which include autophagy, where cells digest and remove old, dysfunctional proteins that accumulate inside cells.
Gene expression: There are changes in the function of genes related to longevity and protection from disease.
These changes in hormone levels, cell function, and gene expression are responsible for the health benefits of intermittent fasting.
In short: When you fast, your human growth hormone level increases, and your insulin levels decrease. The cells in your body also change the expression of genes and initiate important cellular repair processes.
Many studies have been done on intermittent fasting, both in animals and in humans.
These studies have shown that fasting has powerful benefits for weight management and body and brain health. It might even help you live longer.
Key health benefits of intermittent fasting:
Weight Loss: As mentioned above, intermittent fasting can help you lose weight and belly fat without having to consciously restrict calories.
Insulin resistance: Intermittent fasting can reduce insulin resistance, lowering blood sugar by 3-6% and fasting insulin levels by 20-31%, which should protect against type 2 diabetes.
Inflammation: Some studies show reductions in markers of inflammation, a major factor in many chronic diseases.
Heart health: Intermittent fasting can reduce “bad” LDL cholesterol, blood triglycerides, inflammatory markers, blood sugar, and insulin resistance — all risk factors for heart disease.
Cancer: Animal studies suggest that intermittent fasting can prevent cancer.
Brain health: Intermittent fasting increases the brain hormone BDNF and may promote the growth of new nerve cells. It may also protect against Alzheimer's disease.
Anti-aging: Intermittent fasting may extend lifespan in rats. Studies have shown that fasting rats lived 36-83% longer.
Keep in mind that research is still in the early stages. Many of the studies are small, short-term, or tested on animals. Many questions remain to be answered in high-quality human studies.
In short: Intermittent fasting can have many benefits for your body and brain. It helps with weight loss and may reduce the risk of type 2 diabetes, heart disease and cancer. It can also help you live longer.
Makes your healthy lifestyle simpler
Eating healthy is simple, but it can be incredibly difficult to maintain. One of the main obstacles in planning and cooking healthy meals. With intermittent fasting, you don't have to plan, cook, or clean up after as many meals as you used to. For this reason, intermittent fasting is very popular.
In short: One of the main benefits of intermittent fasting is that it simplifies healthy eating. There are fewer meals to prepare, cook, and clean.
Who should avoid or beware of intermittent fasting?
Intermittent fasting is certainly not for everyone.
You should not do it if:
- Are underweight or have a history of eating disorders. Consult a healthcare professional first. In such cases, it can be downright harmful.
- If you have fertility issues and/or are trying to conceive, are pregnant or breastfeeding, consider delaying intermittent fasting.
- Has diabetes.
- Has problems with blood sugar regulation.
- Have low blood pressure.
- Take medication.
- She is a woman with a history of amenorrhea.
In short: People who are underweight or have a history of eating disorders should not fast. There is also some evidence that intermittent fasting can be harmful to some women.
1. Can I drink fluids during the Fast?
Yup. Water, coffee, tea and other non-caloric drinks are fine. Do not add sugar to your coffee. Small amounts of milk or cream may be fine. Coffee can be particularly beneficial during a fast as it can decrease hunger.
2. Is it unhealthy to skip breakfast?
Not. The problem is that most stereotypical breakfast skippers have unhealthy lifestyles. If you make sure you eat healthy foods for the rest of the day, then the practice is perfectly healthy.
3. Can I take supplements on an empty stomach?
Yup. However, keep in mind that some supplements, such as fat-soluble vitamins, may work better when taken with meals.
4. Can I exercise on an empty stomach?
Yes, fasted exercises are good. Some people recommend taking branched-chain amino acids (BCAAs) before a fasted workout.
5. Can Fasting Cause Muscle Loss?
All weight loss methods can cause muscle loss, which is why lifting weights and keeping your protein intake high is important. A 2011 study showed that intermittent fasting causes less muscle loss than regular calorie restriction.
6. Does fasting delay metabolism?
Not. Older studies show that short-term fasts actually increase metabolism. However, longer fasts of 3 or more days can suppress metabolism.
7. Should children fast?
Children should not fast.
Catarina Vilela - Nurse