Fasting is a dietary intervention based on restricted energy intake, which has different forms of frequency and intensity and is effective at reducing body weight and improving metabolic health. However, there are various ways to do it according to everyone’s different lifestyles and goals.
What is Intermittent Fasting?
Do you believe everyone is fasting every day but not everyone knows that?
For example, when you’ve got eight hours of uninterrupted sleep a night, it means you’ve already had an eight-hour intermittent fasting period. Yeah, that’s true!
Instead of focusing on what to eat, intermittent fasting focuses on when to eat.
Based on its definition, intermittent fasting, also called IF, limits the specific time to eat and that to fast (AKA: not eating) in other time while IF.
Why Fasting – The Health Benefits
Blood Sugar Control and Weight Loss
Those who usually have an uncontrolled diet tend to be overweight, dramatically increasing the risk of chronic diseases. At this time, intermittent fasting for a period of time can not only help lose weight but also help reduce fasting blood glucose and postprandial blood glucose. Therefore, intermittent fasting is essentially beneficial to weight loss and blood glucose control. Some experts believe that this method can also enhance the sensitivity of insulin, so it has a certain effect on the prevention and treatment of diabetes.
Beneficial to Heart Health
Common sense: bad eating habits and lifestyles like binge eating and staying up late often leads to unhealthy heart problems. Intermittent Fasting can effectively improve blood lipid level by reducing lipoprotein cholesterol and hunger hormone, which can effectively reduce the risk of heart disease. Moreover, it also improves heart function.
Boosting Sleep and Preventing Alzheimer’s Disease
Intermittent fasting can effectively improve the body’s function, so as to better prolong sleep time, which is very helpful to improve sleep quality. Besides, intermittent fasting can also effectively enhance brain function and better prevent memory loss, so as to achieve the purpose of preventing Alzheimer’s disease. In addition, this diet mode can also restore the polarity of a cell membrane protein to effectively reduce the probability of suffering from Alzheimer’s disease.
Based on the Honoring Clive McCay and 75 Years of Calorie Restriction Research by Roger B. McDonald and Jon J. Ramsey, rats with severely restricted diets lived up to 33% longer than those that don’t. Therefore, limiting the intake of calories as one aspect of Intermittent fasting is beneficial to expand lifespan.
Ask Before Fasting – Who Shouldn’t Try Intermittent Fasting?
In general, intermittent fasting is overall safe for people as it has lots of health benefits on weight loss and immune system boosting. However, not everyone should or need to try it because of their physical condition. A few groups who shouldn’t try intermittent fasting may include:
- Old people (because they possibly lack nutrients from the beginning)
- The adolescents who are at a critical stage of growth and development (because their body needs more nutrients during this period)
- Pregnant women or women trying to become pregnant (because extended fasting periods may throw off your menstrual cycle). Note: for breastfeeding women, it depends on the specific stage they are staying at.
- Those who take diabetes medication (because blood sugar can drop too far in the absence of food)
- Those who take multiple drugs (because food, or lack of it, can affect absorption and dosage)
- Those with extremely low weight (because the fasting period may lead to continued weight loss and health problems may also come)
Some Side Effects Intermittent Fasting May Have
Intermittent Fasting May Make You Feel Hungry
Intermittent fasting is a way to limit your time to eat. So, during the fasting time, you may easily feel hungry especially when you are a fasting beginner.
Intermittent Fasting May Make You Easily Irritate
As an obvious result of intermittent fasting, hunger will bring you low blood sugar and thus may cause a bad mood. But it happens only in the initial stage of intermittent fasting. So when you keep fasting for a period of time, you will gradually adapt and no longer feel angry during fasting time.
Intermittent Fasting May Make You Feel Bloated
As an initial faster, you may restrain yourself from eating to get through the fasting period but have a strong appetite for foods and eat more when you finish the fasting time, which will lead to bloating.
Leading Types of Intermittent Fasting to Pick Up
Once you have the plan of intermittent fasting, you may find that there are many ways to do IF but not every approach is suitable for you because of numerous habits and lifestyles. You can select the one that best fits you after deep considerations. Here are seven types of intermittent fasting for you to consider.
As one of the most popular IF methods, 5:2 fasting suggests that you have 5 days to eat normally without diet limitations but the other 2 days with limited calorie intake. The fasting two days can be any day depending on your choice. Since some people may say “I can do anything for two days, but it’s too much to cut back on what I eat all seven days”, the 5:2 fasting just suits their situation. However, this approach is inadvisable for those who are preparing for a lot of endurance exercises such as a bike or running races as the two fasting days may make them feel weak and lead to a lack of endurance.
When this type of intermittent fasting is adopted, fasters are required to leave a 14 to 16 hours fast every day and set their own eating windows based on their original lifestyle. And women are recommended to leave a fast period not more than 14 hours everyday as it can affect the menstrual cycle and increase the risk for anxiety and depression.
For instance, you can set your eating phase from 8:00 to 6:00, which can avoid missing any meals and is especially convenient for someone with a family to have meals every day. Actually, sleep occupies the most time of the fasting period in this way. But if you have a constantly changing schedule or you want to eat every meal occasionally or you want to go out for a late date night, then this time-restricted fasting is not suitable for you.
Overnight fasting is the simplest way you can take as it requires you to fast for only half of the day-12 hours. For example, you can stop eating after dinner at 7 p.m. and resume eating for breakfast at 7 a.m. of another day. So, it is easy to implement but is still effective in keeping you healthy although you decrease the fasting hours. However, this overnight fasting is not advised for those who want to lose weight through intermittent fasting because a shorter time of fasting may allow you to have more time to consume more calories every day and cannot maximize the advantage of IF.
Eat Stop Eat
Eat stop eat was proposed by author Brad Pilon in his book Eat Stop Eat: The Shocking Truth That Makes Weight Loss Simple Again. In this way, Brad Pilon put more emphasis on flexibility, and he stressed that fasting was just a break from eating. This means that you can complete a plan of taking 24-hour fasting one or two times every week so as to avoid an extreme diet every day and keep a happy mood. By the way, eat stop eat combined with regular weight training is more beneficial for those who want to lose weight.
Whole-day fasting suggests that you only eat once a day. Someone may choose to eat lunch and then not to eat again until the lunch of the next day, which means that you will have 24-hour fasting by adopting this method. However, only one meal for one day is mostly hard for people to insist and it cannot make sure that the human body gets the necessary nutrients to function well through only one meal. Therefore, old people or teenagers who are at the stage of enough nutritional supplements are not advised to take the whole-day fasting.
Alternate-day fasting was proposed by Krista Varady, PhD, a nutrition professor at the University of Illinois in Chicago. It suggests people eat normally on one day and then control the calorie intake to about 500 on another day. A small study published in Nutrition Journal by Dr. Varady and colleagues found that alternate-day fasting was effective in helping obese adults lose weight. But this approach may result in not feeling full of each meal, which can make this type of IF difficult to insist for people.
It can be easily inferred from the name that this approach depends more on yourself. You can choose your own fasting days and change the plan freely. For example, you can take the 5:2 fasting for one week and then adopt the alternate-day fasting for another week. The biggest characteristic of this way is its flexibility and randomness. This may easily be adaptable to your lifestyle and the trend but it may cause an unhealthy diet that is harmful to your body.