Intermittent fasting has become one of the most popular lifestyle trends for weight loss and improving overall health
What is intermittent fasting?
Is it the same as starvation? According to DietDoctor, fasting differs from starvation in one crucial way: control. Starvation is the involuntary absence of food for a long time. This can lead to severe suffering or even death. On the other hand, fasting is the voluntary avoidance of food for spiritual, health, or other reasons. It’s done by someone who is not underweight and has enough stored body fat to live off. When done correctly, fasting should not cause suffering, and certainly never death.
According to Healthline, intermittent fasting is an eating pattern that cycles between periods of fasting and eating. It does not specify which foods you should eat but rather when you should eat them. It is not a diet in the conventional sense but more accurately described as an eating pattern. Common intermittent fasting methods involve daily 16-hour fasts or fasting for 24 hours, twice per week.
Fasting itself has been practiced from thousands of years ago by different cultures and religions. People who still fast for cultural or religious reasons claim that fasting improves their focus, concentration and clarity. There’s also a ton of promising intermittent fasting studies done on rats. They are all reporting positive results-such as weight loss, improved blood pressure, cholesterol, and blood sugars. However, according to Harvard Health Publishing, the studies in humans almost across the board have shown that intermittent fasting is safe and incredibly effective, but really no more effective than any other diet. Aside from that, many people find it difficult to fast and keep it as a lifestyle.
How does intermittent fasting work in weight loss?
When we fast, there are several things in our body on the cellular and molecular level. One of the things is that our body will adjust hormone levels to make our stored body fat more accessible. The food we eat is broken down by enzymes in our gut and eventually ends up as molecules in our bloodstream. Carbohydrates, particularly sugars and refined grains, are quickly broken down into sugar that our cells use for energy.
If our cells do not use the sugars, we will store it in our fat cells. Sugar can only enter our cells with insulin, which brings sugar into the fat cells and keeps it there. When we stop eating, our insulin levels go down and our fat cells can then release the stored sugar, to be used as energy. The entire idea of intermittent fasting is to allow the insulin levels to go down far enough and long enough that we burn off our fat. Not only that, when we fast, our human growth hormone levels go up and our body’s cells also change the expression of genes and initiate important cellular repair processes. So scientifically, there are major health benefits in fasting aside from weight loss.
A 2014 study found that this eating pattern can cause 3–8% weight loss over 3–24 weeks, which is a significant amount, compared to most weight loss studies (1).
How to do intermittent fasting correctly
According to Healthline.com, there are few different ways of doing intermittent fasting. The main idea is splitting the day or week into eating and fasting periods. During these fasting periods, you eat either very little or nothing at all.
These are the most popular methods:
- The 16/8 method: it involves skipping one of your meals in a day (typically breakfast or dinner) and restricting your daily eating period to 8 hours only. Then you fast for 16 hours in between.
- Eat-Stop-Eat: it involves fasting for 24 hours, once or twice a week.
- The 5:2 diet: you consume only 500–600 calories on two non-consecutive days of the week, but eat normally on the other 5 days.
- Alternate-day fasting: you fast every other day.
- The warrior diet: you eat small amounts of raw fruits and vegetables during the day and eat one huge meal at night.
- Spontaneous meal skipping: simply skip meals from time to time when you feel like it (spontaneously).
By reducing your calorie intake, all of these methods should cause weight loss as long as you do not compensate by binge eating during the eating periods. The 16/8 method is the most popular intermittent fasting method. People find it to be the simplest, most sustainable, and easiest to stick to. If you have ever eaten dinner, then slept late, skipped breakfast and gone straight to lunch on the next day, then you have probably already fasted for 16+ hours.
During fasting, you still can drink zero calorie liquids such as black coffee, tea, water, and other non-caloric beverages. You may also have supplements which are best taken with meals.
What are the side effects of intermittent fasting?
Intermittent fasting is certainly not for everyone. According to DietDoctor there are certain people who should not try intermittent fasting, such as:
- People who are underweight (BMI < 18.5) or have an eating disorder like anorexia.
- People who are pregnant
- Breastfeeding mothers
- A child under 18 years old
There are some people with the following conditions who can probably fast, but may need medical supervision:
- People with diabetes mellitus type 1 or type 2.
- People who take prescription medication.
- People who have gout or high uric acid.
- People who have any serious medical conditions, such as liver disease, kidney disease, or heart disease.
For normal and healthy people, hunger is the main side effect of intermittent fasting. In the beginning, they may also feel a little weaker and their brain may not perform as well as they are used to. But this is just temporary. After some time, your body will adapt to the new eating routine.
According to Healthline, there is some evidence that intermittent fasting may not be as beneficial for women as it is for men. Some studies in rats have found that intermittent fasting can make female rats emaciated, masculinized, infertile and cause them to miss cycles. There is no human study on this topic yet. However, there are a number of anecdotal reports of women who experienced absence of menstrual period when they started doing intermittent fasting and went back to normal when they resumed their previous eating pattern. For these reasons, women should be careful with intermittent fasting. Especially if you have issues with fertility and/or are trying to conceive, consider holding off on intermittent fasting for now.
Intermittent fasting is not something that anyone needs to or should do. Some people do not like the adjustment of lifestyle and it can be difficult to maintain, especially in their social life. Intermittent fasting is great for some people, not others. The only way to find out which group you belong to is to give it a try. If you enjoy doing it and find it a sustainable option of dieting, it may be a good idea to keep it.
If you need another option than dieting to lose weight, you could tune in the SureFiz app because we are going to launch meal plan features that are personalized and adjusted based on your body composition data. Subscribe to our newsletter to get yourself updated.
Source: Healthline, DietDoctor, Harvard Health Publishing