Intermittent fasting (IF) is currently one of the world’s most popular health and fitness trends.
People are using it to lose weight, improve their health and simplify their lifestyles.
Many studies show that it can have powerful effects on your body and brain and may even help you live longer.
Here is everything you need to know about intermittent fasting as a beginner.
What is Intermittent fasting?
Intermittent fasting, or intermittent calorie restriction, is an umbrella term for various diets that cycle between a period of fasting and non-fasting during a defined period. Intermittent fasting may produce weight loss comparable to long-term calorie restriction.
It doesn’t specify which foods you should eat but rather when you should eat them.
In this respect, it’s 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 has been a practice throughout human evolution. Ancient hunter-gatherers didn’t have supermarkets, refrigerators or food available year-round. Sometimes they couldn’t find anything to eat.
As a result, humans evolved to be able to function without food for extended periods of time.
In fact, fasting from time to time is more natural than always eating 3–4 (or more) meals per day.
Fasting is also often done for religious or spiritual reasons, including in Islam, Christianity, Judaism and Buddhism.
Benefits of intermittent fasting
Now, I know what you’re probably thinking: What’s wrong with eating whenever you want as long as your meals are from healthy, whole-food sources? Well, giving your body a break from food allows your gut time to rest and inflammation to cool down, thus producing some amazing benefits to your overall health:
Intermittent Fasting Changes The Function of Cells, Genes and Hormones
When you don’t eat for a while, several things happen in your body.
For example, your body initiates important cellular repair processes and changes hormone levels to make stored body fat more accessible.
Here are some of the changes that occur in your body during fasting:
- Insulin levels:Blood levels of insulin drop significantly, which facilitates fat burning.
- Human growth hormone:The blood levels of growth hormone may increase as much as 5-fold. Higher levels of this hormone facilitate fat burning and muscle gain, and have numerous other benefits.
- Cellular repair:The body induces important cellular repair processes, such as removing waste material from cells.
- Gene expression:There are beneficial changes in several genes and molecules related to longevity and protection against disease.
Many of the benefits of intermittent fasting are related to these changes in hormones, gene expression and function of cells.
Lowers cancer risk
Multiple studies have shown a link between intermittent fasting and a reduced risk of breast cancer.
3. Enhances heart health
Intermittent fasting is thought to lower heart disease risk due to its ability to lower triglycerides and blood pressure and raise beneficial HDL cholesterol.
Improves autoimmune conditions
A fasting-mimicking diet under 1,000 calories a day for three-day cycles has been shown to improve symptoms associated with autoimmune conditions like multiple sclerosis as well as lupus.
Improves blood sugar.
When it comes to managing blood sugar, intermittent fasting takes centre stage. With its proven ability to lower insulin resistance and increase metabolism, it’s one of my favorite tools to recommend to patients with blood sugar problems.
Encourages weight loss
Weight-loss resistance can often be due to an underlying hormone imbalance. Leptin resistance occurs when your brain stops recognizing leptin’s signals to use your body’s fat stores for energy. This causes your body to continually store fat instead of using it. Intermittent fasting has been shown to improve chronic inflammation that can dull the brain’s leptin receptor sites.
If you’re worried you’ll be starving while fasting, you’ll be pleasantly surprised! Intermittent fasting decreases your hunger hormone ghrelin, which in turn can increase dopamine levels in the brain. (Just another example of the gut-brain axis at work.) Fasting can also help free people from emotional eating and kill cravings by transitioning your metabolism from unstable sugar-burning to steady fat-burning.
Increases cognitive function
Studies have shown that intermittent fasting can improve degenerative brain disorders such as Alzheimer’s and Parkinson’s.
Improves lung health.
One study showed intermittent fasting’s ability to decrease asthma symptomsas well as reduce oxidative stress.
Helps heal the gut
Lowering inflammation in the gut with intermittent fasting improves inflammatory gut problems such as IBS, ulcerative colitis, and Crohn’s disease.
Intermittent Fasting May Extend Your Lifespan, Helping You Live Longer
One of the most exciting applications of intermittent fasting may be its ability to extend lifespan.
Studies in rats have shown that intermittent fasting extends lifespan in a similar way as continuous calorie restriction.
In some of these studies, the effects were quite dramatic. In one of them, rats that fasted every other day lived 83% longer than rats who weren’t fasted.
Although this is far from being proven in humans, intermittent fasting has become very popular among the anti-aging crowd.
Given the known benefits for metabolism and all sorts of health markers, it makes sense that intermittent fasting could help you live a longer and healthier life.
While the idea of fasting can be overwhelming, especially if you haven’t done it before, intermittent fasting can actually be a lot easier than many other types of eating plans. Since you are fasting for a good chunk of the day, you’ll be eating less food, which eliminates a lot of the stress around having to meal prep. When you are eating, you’ll still want to focus mainly on healthy fats, clean protein, and carbohydrates from whole food sources—but this isn’t an excuse to hit the drive-thru and load up on sugar the rest of the time!
3 Methods for Intermittent Fasting
There are several different ways of doing intermittent fasting — all of which involve splitting the day or week into eating and fasting periods.
During the fasting periods, you eat either very little or nothing at all.
These are the most popular methods:
- The 16/8 method:Also called the Leangains protocol, it involves skipping breakfast and restricting your daily eating period to 8 hours, such as 1–9 p.m. Then you fast for 16 hours in between.
- Eat-Stop-Eat:This involves fasting for 24 hours, once or twice a week, for example by not eating from dinner one day until dinner the next day.
- The 5:2 diet:With this methods, you consume only 500–600 calories on two non-consecutive days of the week, but eat normally the other 5 days.
By reducing your calorie intake, all of these methods should cause weight loss as long as you don’t compensate by eating much more during the eating periods.
Many people find the 16/8 method to be the simplest, most sustainable and easiest to stick to. It’s also the most popular.
Who Should Be Careful Or Avoid It?
Intermittent fasting is certainly not for everyone.
If you’re underweight or have a history of eating disorders, you should not fast without consulting with a health professional first.
In these cases, it can be downright harmful.
Should Women Fast?
There is some evidence that intermittent fasting may not be as beneficial for women as it is for men.
For example, one study showed that it improved insulin sensitivity in men, but worsened blood sugar control in women.
Though human studies on this topic are unavailable, studies in rats have found that intermittent fasting can make female rats emaciated, masculinized, infertile and cause them to miss cycles.
There are a number of anecdotal reports of women whose menstrual period stopped when they started doing IF and went back to normal when they resumed their previous eating pattern.
For these reasons, women should be careful with intermittent fasting.
They should follow separate guidelines, like easing into the practice and stopping immediately if they have any problems like amenorrhea (absence of menstruation).
If you have issues with fertility and/or are trying to conceive, consider holding off on intermittent fasting for now. This eating pattern is likely also a bad idea if you’re pregnant or breastfeeding.
Common questions about intermittent fasting
Here are answers to the most common questions about intermittent fasting.
1. Can I Drink Liquids During the Fast?
Yes. Water, coffee, tea and other non-caloric beverages are fine. Do not add sugar to your coffee. Small amounts of milk or cream may be okay.
Coffee can be particularly beneficial during a fast, as it can blunt hunger.
2. Isn’t It Unhealthy to Skip Breakfast?
No. The problem is that most stereotypical breakfast skippers have unhealthy lifestyles. If you make sure to eat healthy food for the rest of the day then the practice is perfectly healthy.
3. Can I Take Supplements While Fasting?
Yes. However, keep in mind that some supplements like fat-soluble vitamins may work better when taken with meals.
4. Can I Work out While Fasted?
Yes, fasted workouts are fine. Some people recommend taking branched-chain amino acids (BCAAs) before a fasted workout.
5. Will Fasting Cause Muscle Loss?
All weight loss methods can cause muscle loss, which is why it’s important to lift weights and keep your protein intake high. One study showed that intermittent fasting causes less muscle loss than regular calorie restriction.
6. Will Fasting Slow Down My Metabolism?
No. Studies show that short-term fasts actually boost metabolism. However, longer fasts of 3 or more days can suppress metabolism.
7. Should Kids Fast?
Allowing your child to fast is probably a bad idea.
Getting StartedWith Intermittent Fasting
Chances are that you’ve already done many intermittent fasts in your life.
If you’ve ever eaten dinner, then slept late and not eaten until lunch the next day, then you’ve probably already fasted for 16+ hours.
Some people instinctively eat this way. They simply don’t feel hungry in the morning.
Many people consider the 16/8 method the simplest and most sustainable way of intermittent fasting — you might want to try this practice first.
If you find it easy and feel good during the fast, then maybe try moving on to more advanced fasts like 24-hour fasts 1–2 times per week (Eat-Stop-Eat) or only eating 500–600 calories 1–2 days per week (5:2 diet).
Another approach is to simply fast whenever it’s convenient — simply skip meals from time to time when you’re not hungry or don’t have time to cook.
There is no need to follow a structured intermittent fasting plan to derive at least some of the benefits.
Experiment with the different approaches and find something that you enjoy and fits your schedule.
Intermittent fasting: Is it for you?
Intermittent fasting is not something that anyone needs to do.
It’s simply one of many lifestyle strategies that can improve your health. Eating real food, exercising and taking care of your sleep are still the most important factors to focus on.
If you don’t like the idea of fasting, then you can safely ignore this article and continue to do what works for you.
At the end of the day, there is no one-size-fits-all solution when it comes to nutrition. The best diet for you is the one you can stick to in the long run.
Intermittent fasting is great for some people, not others. The only way to find out which group you belong to is to try it out.
If you feel good when fasting and find it to be a sustainable way of eating, it can be a very powerful tool to lose weight and improve your health.
Hunger is the main side effect of intermittent fasting.
You may also feel weak and your brain may not perform as well as you’re used to.
This may only be temporary, as it can take some time for your body to adapt to the new meal schedule.
If you have a medical condition, you should consult with your doctor before trying intermittent fasting.
This is particularly important if you:
- Have diabetes.
- Have problems with blood sugar regulation.
- Have low blood pressure.
- Take medications.
- Are underweight.
- Have a history of eating disorders.
- Are a woman who is trying to conceive.
- Are a woman with a history of amenorrhea.
- Are pregnant or breastfeeding.
All that being said, intermittent fasting has an outstanding safety profile. There is nothing dangerous about not eating for a while if you’re healthy and well-nourished overall.