Known as IF for short, intermittent fasting is one of the most popular health and fitness trends around the world.
People use it to lose weight, enhance their health and simplify their lives. Studies reveal it can have significant effects on the body and brain and could even help you to live longer,
Check out our beginner’s guide to intermittent fasting below.
What Is Intermittent Fasting (IF)?
Intermittent fasting (IF), an eating pattern cycling between periods of fasting and eating, doesn’t say which foods you should eat but instead tells you when you should eat them. That’s why it doesn’t fall under the category of a conventional diet. It’s more of an eating pattern.
The most common IF methods involve 16-hour fasts daily or fasting for 24 hours, two times per week. Fasting is nothing new. Ancient hunter-gatherers did not have grocery stores, and didn’t have the benefits of refrigerators. They didn’t even have the promise of food being available year-round. That’s why, in order to function without food for long periods of time, they had to fast. This is actually a more natural way of eating than having three to four meals a day.
People also fast for religious or spiritual reasons, including in Christianity, Judaism, Islam, and Buddhism faiths.
Intermittent fasting (IF), an eating pattern cycling between periods of fasting and eating, doesn’t say which foods you should eat but instead tells you when you should eat them.
There are many ways you can do intermittent fasting. They all require you to split the day or week into fasting and eating periods.
While fasting, you don’t eat anything, or very little.
The most popular methods include:
The 16/8 method: Also known as the Leangains protocol, you would skip breakfast and restrict your daily eating period to fall within just eight hours, such as 11–7 p.m. Then you would fast for those 16 hours in between.
Eat-Stop-Eat: You would fast for 24 hours, one or two times a week. For instance, maybe you wouldn’t eat from dinner one day until dinner time the next.
The 5:2 diet: Using this method, you eat only 500–600 calories on two non-consecutive days, while eating normally the other five days.
When you reduce your caloric intake, any of the above methods should lead to weight loss, provided you don’t overeat during your eating periods.
Many people think that the 16/8 method is the easiest because it’s the most sustainable. This method also happens to be the most popular.
There are many ways you can do intermittent fasting. They all require you to split the day or week into fasting and eating periods.
How IF Impacts Cells and Hormones
When you start to fast, many things are happening in your body on both the cellular and molecular levels. For one thing, your body will adjust its hormone levels to ensure stored body fat is more accessible. Also, your cells start the repair process and switch up the expression of genes.
Check out these changes that occur when you fast:
- Human Growth Hormone (HGH): The levels of growth hormone go up by as much as five-fold. This allows for fat loss and muscle gain.
- Insulin: Insulin sensitivity is enhanced and levels of insulin will drop drastically. Lower insulin levels ensure stored body fat becomes more accessible
- Cellular repair: Fasting cells begin the cellular repair process, including autophagy. This is when your cells digest and remove dysfunctional, old proteins that have built up inside your cells
- Gene expression: Gene function changes related to longevity and disease protection.
These changes in cell function, hormone levels, and gene expression are what give you the health benefits of intermittent fasting.
When fasting, insulin levels go down and human growth hormone levels go up. Your cells also switch up gene expression while starting the cellular repair process.
IF: A Powerful Weight Loss Tool
Weight loss is the most popular reason people want to start intermittent fasting.
By eating fewer meals, IF can result in an automatic reduction in caloric intake.
Also, IF changes hormone levels to ensure weight loss.
On top of reducing insulin and boosting growth hormone levels, IF boosts the release of norepinephrine (noradrenaline), a fat-burning hormone.
Due to these hormonal changes, short-term fasting can increase your metabolic rate by about four percent to 14 percent.
When you eat fewer calories and burn more calories, intermittent fasting leads to weight loss because it changes both sides of the caloric equation.
Studies reveal that IF is a powerful weight loss tool.
One study found that this eating pattern may cause between three and eight percent weight loss over a period of between three and 24 weeks. The same study found that participants lost four to seven percent of their waist circumference, leading to a significant loss of belly fat that can build up harmfully around the organs and result in disease.
An additional study revealed that IF causes less muscle loss than continuous caloric restriction.
But remember that intermittent fasting helps you to consume fewer calories overall. If you binge during your eating periods and take in too many calories, you probably won’t lose weight.
Intermittent fasting can enhance metabolism while helping you consume fewer calories. Thus, it is an effective way to lose belly fat and weight overall.
Health Benefits of IF
Many studies have shown that IF has powerful benefits for controlling weight and improving the health of your body and brain. You may even be able to live longer.
Check out the top health benefits of intermittent fasting:
- Weight loss: IF helps you lose weight and belly fat, without the need to restrict calories all day long
- Anti-aging: This method has been shown to extend rats’ lifespan. Studies show that fasting rats lived 36 to 83 percent longer
- Inflammation: IF can reduce reductions in inflammation markers, an important cause of chronic diseases
- Heart health: IF can reduce “bad” LDL cholesterol, blood triglycerides, blood sugar and insulin resistance, and inflammatory markers, which are all risk factors of heart disease
- Insulin resistance: Intermittent fasting reduces insulin resistance, reducing blood sugar by three to six percent, as well as fasting insulin levels by 20 to 31 percent, offering protection against type 2 diabetes
- Cancer: Animal studies show IF could prevent cancer
- Brain health: IF boosts the brain hormone BDNF and could help with the growth of new nerve cells. It could also offer protection against Alzheimer’s disease
In the end, the research is still being done and we need to know more about IF. Many studies so far are small, short-term or done on animals. We need higher quality human studies to know more.
Intermittent fasting has several benefits for the body and brain. It may result in weight loss while reducing the risk of type 2 diabetes, cancer and heart disease. You could also live longer.
IF: Making a Healthy Lifestyle Simpler
Eating healthy may start out easy, but it’s very hard to maintain over the long term. One of the biggest challenges is all the work you have to put in to plan out a menu and then cook healthy meals.
IF may make this easier on you. That’s because you don’t have to plan, cook or clean after a lot of meals like you did before. This is why IF is popular with the life-hacking crowd, as it boosts your health while simplifying lifestyles.
One of the biggest advantages of intermittent fasting is that it simplifies healthy eating. You don’t have to plan for, prepare and consume as many meals as you used to.
Who Should Be Careful With IF or Avoid It Altogether?
Intermittent fasting isn’t for everyone.
If you are underweight or have had an eating disorder in the past, do not attempt fasting without first talking with your doctor. That’s because IF can be harmful to your health.
Should Females Fast?
Evidence suggests that IF may not have as many benefits for women as for men. One study showed IF improved insulin sensitivity in males, but lowered blood sugar control in females.
Human studies on this topic are currently unavailable, rat studies have shown that IF can lead to emaciation in female rats, while also making them masculinized and infertile. They also missed cycles.
There are many reports of females whose menstrual period stopped when they began IF and then resumed normal cycles when getting off IF. This is why women should be careful when deciding to do intermittent fasting.
Females should follow separate guidelines, such as easing into IF slowly and stopping if they experience problems such as amenorrhea, which is the absence of menstruation.
Females who have issues with fertility or who are trying to conceive should hold off on intermittent fasting. This eating pattern is also not for those women who are pregnant or breastfeeding.
Underweight people and those with a history of eating disorders shouldn’t fast. Evidence shows that intermittent fasting could be harmful to some women.
Safety and Side Effects of IF
Hunger is the most common side effect of intermittent fasting. People could also feel weak and their brains may not function optimally.
These effects may be temporary, as it does take time for the body to adapt to a new eating pattern.
Those with medical conditions should consult with their doctor before trying IF.
This is critical if you:
- Have diabetes.
- Have issues with blood sugar regulation.
- Take medications.
- Are underweight.
- Have had an eating disorder.
- Have low blood pressure.
- Are trying to conceive.
- Have a history of amenorrhea.
- Are pregnant or breastfeeding.
With that said, intermittent fasting has been proven safe for most people, as long as you eat a healthy, well-nourished diet.
The biggest side effect of intermittent fasting is hunger. Those with certain medical conditions shouldn’t fast without asking their doctor first.
Check out these most common questions about IF.
1. Can You Drink Liquids During Fasting?
Yes. You may drink water, coffee, tea and other non-calorie beverages, but don’t add sugar to your coffee or tea. Coffee is great during a fast, as it lessens hunger.
2. Is It Unhealthy to Skip Breakfast?
Not always. Most stereotypical breakfast skippers also lead unhealthy lifestyles. If you eat healthy food for your eating window, then it’s perfectly fine to skip breakfast.
3. Can You Take Supplements While Fasting?
Yes, but some supplements such as fat-soluble vitamins work better when you take them with meals.
4. Can You Work Out While Fasting?
Yes, but some people recommend popping branched-chain amino acids (BCAAs) before a workout during fasting. Check out these BCAA products on Amazon.
5. Will Fasting Lead to Muscle Loss?
While all weight loss methods may cause muscle loss, you should make it a point to lift weights and increase your protein intake. Studies show that intermittent fasting leads to less muscle loss than standard caloric restriction.
6. Will Fasting Slow Your Metabolism?
No. Studies reveal that short-term fasts can actually enhance metabolism. However, if you engage in longer fasts of three or more days, this can suppress metabolism.
7. Should Kids Do IF?
This isn’t a good idea.
How to Get Started
You may have done other intermittent fasts in your lifetime, such as when you have had dinner, then slept late the next day and didn’t eat until lunch. That means you already fasted for 16 hours.
Some people eat this way out of habit without realizing they are fasting. They just don’t feel hungry in the mornings.
Many think the 16/8 method the easiest and most sustainable way of engaging in IF, so you may want to start out with this method.
If you feel good with this and find it easy, move on to more advanced fasts such as 24-hour fasts one to two times a week (Eat-Stop-Eat) or only consuming 500–600 calories one to two days a week (5:2 diet).
You could also just fast whenever it is convenient for you, skipping meals periodically when you aren’t hungry or don’t feel like cooking.
You don’t always have to follow a structured intermittent fasting plan to get some benefits.
Try experimenting with different approaches to land on something you enjoy and that fits with your schedule.
Most people start with the 16/8 method, then move on to other methods later if that works for them. Experiment with the method that works best for you.
Should You Try IF?
Intermittent fasting is not for everyone; it’s just one of many lifestyle changes that can boost your health. Eating healthy, real food, exercising and sleeping well are all important too.
There’s really no one-size-fits-all solution in regards to nutrition. The best diet is the one that’s sustainable and enjoyable.
Intermittent fasting works for some people, but not for others. The only way you will know is to give it a try and see.
If you feel good as you fast, it may end up being a sustainable way of eating for you, resulting in weight loss and health improvements.
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