The Beginner’s Guide to Intermittent Fasting
Intermittent fasting is currently one of the world’s most popular health and fitness trends. Intermittent fasting is when you go without food for a certain amount of time. That kind of seems scary to a lot people, but intermittent fasting can actually be a lot easier than many other types of meal plans or diets.
You’ll be eating less food, which takes away a lot of the stress around having to meal prep. After all, life is all about balance!
Intermittent fasting is better described as an eating pattern rather than a ‘diet’, and there is actually a solid amount of scientific evidence supporting its benefits – including weight loss, mental clarity and improved metabolism.
Intermittent fasting provides huge benefits if it is done right, including weight loss, lower inflammation, increased energy, a higher metabolism and lot more.
The goal of this beginner’s guide is to provide everything you need to know about intermittent fasting.
What Is Intermittent Fasting?
Intermittent fasting is an eating pattern that cycles between periods of fasting and eating; an eating window and a fasting window.
To understand intermittent fasting, you need to understand that it’s not a diet. It’s a specific pattern of eating that is going to change your body for the better.
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 or a way of timing your meals.
Intermittent fasting is not a diet, but rather an eating pattern.
By fasting and then feasting on purpose, intermittent fasting generally means that you consume your calories during a specific window of the day, and choose not to eat food for a larger window of time.
Intermittent Fasting Methods
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.
What most people do (including myself) is eat nothing in the morning except for water and black coffee. I normally eat eggs with lots of veggies around noon, and then my last meal is around 7:30 or 8pm.
Most Popular Methods
The 16/8 Method (or Leangains)
Many people find the 16/8 method to be the simplest, most sustainable and easiest to stick to. It’s also the most popular. It involves skipping breakfast and restricting your daily eating period to 8 hours, like 12-8 like I do. Then you fast for 16 hours in between. Basically it’s just skipping one meal!
Some people only eat in a 6-hour window, or even a 4-hour window. This is “feasting” and “fasting” parts of your days and the most common form of intermittent fasting.
It fits pretty seamlessly into most lifestyles, seeing as how you can choose to skip either breakfast or dinner, depending on your personal preferences. Also, you’re sleeping during a good chunk of the fasting window, which makes it easier.
This schedule is good for just about anyone, but especially if you’ve already experimented with shorter fasting windows, you might want to give this one a try. It tends to hit the sweet spot for most people as far as being manageable while still providing noticeable benefits.
You can adjust this window to make it work for your life.
24 Hour Fasting
This way of doing intermittent fasting involves fasting from dinner to dinner (or lunch to lunch). If you eat dinner on day 1, you would skip the next day’s breakfast and lunch and eat dinner again on day 2. This means that you are still eating daily, but only once during that day. This would generally be done two to three times per week. If you’re just starting out, you may even do just one day a week.
Fasting completely for 1 or 2 days a week, known as the Eat-Stop-Eat diet, involves eating no food for 24 hours at a time. Many people fast from breakfast to breakfast or lunch to lunch.
Skipping two meals one day, where you are taking 24 hours off from eating. For example, eating on a normal schedule (finishing dinner at 8PM) and then not eating again until 8PM the following day.
People on this diet plan can have water, tea, and other calorie-free drinks during the fasting period.
A 24-hour fast can be challenging, and it might cause irritability, fatigue, and/or headaches. Many people find that these effects become less extreme over time. Your body just needs time to adjust to this new pattern of eating.
Some people may benefit from trying a 12-hour or 16-hour fast before transitioning to the 24-hour fast.
You would eat your normal 3 meals per day, and then occasionally pick a day to skip breakfast and lunch the next day.
If you can only do an 18 hour fast, or a 20 hour fast, or a 22 hour fast – that’s okay! Adjust with different time frames and see how your body responds.
The 5:2 Diet
With this method, you consume only 500–600 calories on two non-consecutive days of the week, but eat normally the other 5 days.
One common way of planning the week is to fast on Mondays and Thursdays, with two or three small meals, then eat normally for the rest of the week.
You can choose whichever two days of the week you prefer, as long as there is at least one non-fasting day in between them.
For example, you can fast on Monday and Thursday but eat clean meals on the other days. Food on these five days will look just like the rest of the fasting plans—healthy fats, clean meat sources, vegetables, and some fruit.
Keep in mind that this plan is not for beginners, and you should always talk to your doctor before starting any fasting regimen, especially if you are on medication or have a medical condition.
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.
Intermittent fasting is a powerful approach that facilitates weight loss and helps reduce your risk of chronic diseases like type 2 diabetes, heart disease and cancer. A large and growing body of medical research supports the use of intermittent fasting, showing it has a wide range of benefits.
Weight loss is the most common reason for people to try intermittent fasting.
Intermittent fasting can help you lose weight and belly fat, without having to consciously restrict calories.
By making you eat fewer meals, intermittent fasting can lead to an automatic reduction in calorie intake.
Intermittent fasting can fast-track your weight loss goals by busting stubborn fat, reducing calories, and rewiring your metabolism for better performance.
A 2014 review 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.
According to the same study, people also lost 4–7% of their waist circumference, indicating a significant loss of harmful, stubborn belly fat or visceral fat that is packed deep around your abdominal organs.
During a period of six months, people on an intermittent fasting diet were able to shed four to seven percent of their visceral fat.
Another study showed that intermittent fasting causes less muscle loss than the more standard method of continuous calorie restriction.
However, keep in mind that the main reason for its success with intermittent fasting is that it helps you eat fewer calories overall. If you binge during your eating periods, you may not lose any weight at all.
Studies show that intermittent fasting also accelerates weight loss. In a 2015 review pooling 40 different studies, participants shed on average 10 pounds in a 10-week period. Another study found that obese adults following an “alternate day” intermittent fasting schedule (eating 25 percent of their daily calories on one day, and eating normally the following day) lost up to 13 pounds over 8 weeks.
When you’re in the fasted state your body can burn fat that has been inaccessible during the fed state.
Because we don’t enter the fasted state until 12 hours after our last meal, it’s rare that our bodies are in this fat burning state. This is one of the reasons why many people who start intermittent fasting will lose fat without changing what they eat, how much they eat, or how often they exercise. Fasting puts your body in a fat burning state that you rarely make it to during a normal eating schedule.
How It Affects Your Cells and Hormones
When you fast, several things happen in your body on the cellular and molecular level.
For example, your body adjusts hormone levels to make stored body fat more accessible. Your cells also initiate important repair processes and change the expression of genes.
Here are some changes that occur in your body when you fast:
Cellular repair: When fasted, your cells initiate cellular repair processes. This includes autophagy, where cells digest and remove old and dysfunctional proteins that build up inside cells. The list goes on and on. But how can one simple practice possibly do all this? Autophagy is what happens in the body when cells clean house and the weak ones die off. This makes room for the regeneration of new, healthier cells and tissues, which affects longevity and helps reverse diseases of all kinds. It’s even been shown to play a role in decreasing inflammation and improving immunity. In other words, fasting gives your body a break from digesting and allows it to focus on other things.
• Human Growth Hormone (HGH): The levels of growth hormone skyrocket, increasing as much as 5-fold. This has benefits for fat loss and muscle gain, to name a few.
• Insulin: Insulin sensitivity improves and levels of insulin drop dramatically. Lower insulin levels make stored body fat more accessible.
• Gene expression: There are changes in the function of genes related to longevity and protection against disease.
These changes in hormone levels, cell function and gene expression are responsible for the health benefits of intermittent fasting.
When you fast, human growth hormone levels go up and insulin levels go down. Your body’s cells also change the expression of genes and initiate important cellular repair processes. In addition to lowering insulin and increasing growth hormone levels, it increases the release of the fat burning hormone norepinephrine (noradrenaline). Because of these changes in hormones, short-term fasting may increase your metabolic rate by 3.6–14%.
It Simplifies Your Life
Keep it Simple
When you adopt an intermittent fasting lifestyle, well it just makes your life much easier!
The reason most diets fail isn’t because we switch to the wrong foods, it’s because we don’t actually follow the diet over the long term. It’s not a nutrition problem, it’s a behavior change problem.
Before I practiced intermittent fasting, I obsessed about waking up early to cook breakfast, prep 6 meals a day, etc. Now that I intermittent fast, my life is a lot more simple. I eat one or two major meals a day, I don’t obsess about what I eat and still make consistent progress to improve my health every day. Simplifying my life in this way has freed up more time and energy to focus on what really matters to me.
Eating healthy is simple, but it can be incredibly hard to maintain. One of the main obstacles is all the work required to plan for and cook healthy meals. Intermittent fasting can make things easier, as you don’t need to plan, cook or clean up after as many meals as before.
Health and simplicity go hand and hand. The healthiest foods are often the simplest, like a banana or a piece of lean chicken breast. These basic foods are some of the healthiest you can eat, and being healthy should be simple. 2-3 large healthy meals per day are much easier to manage than 6 normal-sized meals and snacks.
Intermittent fasting improves your health while simplifying your life at the same time.
Other Benefits of Intermittent Fasting
- Reduces inflammation: Lowering inflammation is key to losing weight, boosting longevity, and reducing your risk of major illnesses such as Alzheimer’s and cancer. Intermittent fasting decreases oxidative stress and inflammation across the board. Some studies show reductions in markers of inflammation, such as adiponectin, leptin, and brain-derived neurotrophic factor.
- Lowers insulin levels: Intermittent fasting acts on insulin in two ways. First, it boosts your adiponectin levels, which helps restore insulin sensitivity to prevent weight gain and diabetes. Second, fasting decreases your fasting insulin levels. Lowered insulin is the cue your body needs to make the switch to burning stored fat instead of glucose. 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.
- Heart health: Intermittent fasting may reduce “bad” LDL cholesterol, blood triglycerides, inflammatory markers, blood sugar and insulin resistance — all risk factors for heart disease Studies show that intermittent fasting can improve numerous risk factors for heart disease such as blood pressure, cholesterol levels, triglycerides and inflammatory markers.
- Cancer: Animal studies suggest that intermittent fasting may prevent cancer.
- Brain health: Intermittent fasting increases the brain hormone BDNF and may aid the growth of new nerve cells. It may also protect against Alzheimer’s disease.
- Anti-aging: Intermittent fasting can extend lifespan in rats. Studies showed that fasted rats lived 36–83% longer.
Keep in mind that research is still in its early stages. Many of the studies were small, short-term or conducted in animals. Many questions have yet to be answered in higher quality human studies.
Side Effects and Safety
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.
Frequently Asked Questions
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. There is no scientific evidence that proves that eating a meal in the morning will help boost your metabolism. If anything, it’s just extra calories that your body may not need. If you aren’t hungry, don’t eat. Wait until lunch and have a big lunch.
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?
Nah. Let kids be kids.
Many people consider the 16/8 method the simplest and most sustainable way of intermittent fasting — this is a good place to start.
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. 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. Remember, this is to simplify your life!
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.
Fasting and a change in your diet are only going to improve your health even more, but starting with intermittent fasting is a good step in the right direction.
If you’re able to stick to the 8-hour windows where you eat and give your body the other 16 hours of the day to focus on other processes that need to happen, your body is going to thank you.