If you’ve been curious about intermittent fasting, you’re in the right place.
This comprehensive Intermittent Fasting 101 Guide will take you through the basics and give you practical tools to start implementing fasting. It will answer all of your questions and provide you with clarity on whether or not fasting is for you.
Let’s dive in!
What is Intermittent Fasting?
Intermittent fasting is defined as not eating for a set period of time followed by an “eating window”. The amount of time you’re fasting can range from 12 hours to over 24 hours. It can be daily, a few times a week, or even once a month.
We’ve all heard of fasting. Most of us are familiar with people fasting for religious purposes or having to fast before a medical test.
And for many people, it’s pretty intimidating to think about not eating for a period of time. Purposefully deciding not to eat, well, that’s a whole different story.
Intermittent fasting has been gaining in popularity the last few years, and many people are practicing it for health purposes and to lose weight.
There are many different approaches to intermittent fasting and no right or wrong way to do it.
If you’re thinking about trying it, start slow and take time to figure out what approach works best for you.
When you decide to incorporate intermittent fasting into your life, take time to determine your “why”. Intermittent fasting isn’t a quick fix and like any changes to your eating habits, consistency over time is key for success.
In general, it’s best to ease into fasting. Research supports health benefits from fasting at least 12 hours a day and most people can easily do this overnight.
For example, if you finish your last meal of the day at 7pm, make sure you don’t eat your first meal until after 7am the next day. Simple enough, but this can be difficult if you typically eat a late dinner and/or early breakfast.
Start by fasting 12 hours and then work on extending your fast over the next several weeks to 13 hours, 14 hours, 15 hours, and eventually 16 hours or longer.
The most common schedule is to fast for 16 hours with an eight-hour eating window.
As mentioned above, the most popular fasting method is to fast for 16 hours with an eight-hour eating window (16:8).
Many people who fast follow the 16:8 eating pattern. With this approach, you could finish dinner by 7pm and then eat your first meal the next day after 11am.
For most people, they just skip breakfast and end up eating two or three meals during the day.
Other approaches to fasting
While fasting for 16 hours is one of the most practiced approaches to intermittent fasting, there are other options. Many people fast for 20 hours and have only a four-hour eating window (20:4).
Another way of fasting is to do a 24-hour fast two days a week and then eat normally the other five days. With this method, the fasting days typically have two or three normal eating days between them.
Some people do alternate day fasting and practice full 24-hour fasts every other day of the week, which would be fasting three to four times a week and then having three to four normal eating days.
Whatever approach you decide to take when it comes to fasting, make sure you ease into it and consult with your doctor before starting.
Will I be hungry?
It’s interesting that for many people, once they make up their mind to fast, it becomes easier.
When you plan on skipping a meal, you’re okay with not eating versus missing a planned meal because you were busy.
Missing a planned meal typically leads to those extreme hunger pangs and feeling “hangry”.
Making the decision to not eat is much different. A large portion of intermittent fasting is all about your mindset.
The longer you practice fasting, the easier it gets. Yes, you might get hungry at times but it’s manageable hunger.
What you eat during your eating window can also impact your hunger levels. Focusing on protein will help keep you full for longer periods of time.
What is allowed?
The goal of intermittent fasting is to keep your blood sugar and insulin levels stable. As soon as glucose or insulin rises, you are no longer fasting.
Any solid food that you eat will kick you out of a fasted state.
Non-caloric beverages are allowed during fasting. This includes:
- Black coffee
- Plain tea
It’s debated whether or not adding plain heavy whipping cream to your coffee or tea will kick you out of a fasted state. Generally there’s some individual variability and the only true way to know is to check your blood sugars.
What to eat when you break your fast
It’s important to make healthy food choices during your eating window. Think of each meal as an opportunity to nourish your body.
Can I Eat Whatever I want?
There’s a misconception that you can eat whatever you want when you’re not fasting, and that it’s okay to splurge because you’ve been depriving yourself. This is a mindset that will not lead to improved health or weight loss.
Eating the right foods when you break your fast is key for successful weight loss and to achieve the health benefits of fasting.
The main priority when you eat is meeting your protein goals. Ideally, you need to aim for 30 to 50 grams of protein at your first and last meal. If you’re eating a third meal, try to get at least 25 grams of protein.
Pair protein with vegetables and a small serving of a starchy food if desired.
You should not constantly be eating during your eating window. It is best to eat only two to three meals or snacks during this time. Most often people eat two large meals and maybe a snack between the meals.
The goal is still to keep your blood sugars and insulin as stable as possible.
Think of the time between your meals as little “mini” fasts. If you’re hungry two hours after a meal, you likely didn’t eat enough protein at that meal. You should be able to go about four hours without getting hungry.
Is it safe?
Yes! Intermittent fasting is perfectly safe. It is always recommended that you discuss any dietary changes with your medical provider before starting though.
If someone has a history of an eating disorder, fasting may be contraindicated.
Disclaimer that if you have certain medical conditions such as diabetes and take insulin or other diabetic medications, you need to discuss fasting with your medical provider as they may need to adjust your medications and you could be at risk for hypoglycemia.
Research has shown many benefits to fasting. It can help with weight loss, diabetes, and overall improved health.
One of the main reasons people practice intermittent fasting is for weight loss. Research shows it helps with weight loss in a number of ways.
During fasting, your body will go into ketosis. Ketosis is when your body is burning fat for fuel instead of carbohydrates. With intermittent fasting, you’ll be burning your own fat stores for energy, which leads to weight loss.
This is why it can also be beneficial to follow a low-carbohydrate diet during your eating window. You can stay in ketosis and continue to burn fat for fuel if you keep your blood sugar and insulin levels stable.
For many people, intermittent fasting is a form of calorie restriction. By only eating two meals a day, you eliminate one full meal and thus reduce your total caloric intake. Research shows that being in a calorie deficit leads to weight loss.
Blood Sugar Control
For those with diabetes, intermittent fasting can greatly help improve blood sugars. It’s amazing what happens to your glucose and insulin levels when you’re not eating.
When you’re fasting, your body is forced to use the glucose that’s in your bloodstream. This will bring elevated blood sugars back down to a normal level. When blood sugars are stable, insulin levels will also stabilize.
Reducing blood sugars also lowers inflammation.
A word of caution though, if you are on certain medications for diabetes, they can cause your blood sugars to drop too low (hypoglycemia) while fasting.
- Sulfonylureas (increases pancreatic insulin secretion)
- Gliclazide (Diamicron)
- Glimepiride (Amaryl)
- Glyburide (Diabeta)
- Meglitinides (increases pancreatic insulin secretion)
- Nateglinide (Starlix)
- Repaglinide (GlucoNorm)
- Exogenous insulin
- SGLT2 Inhibitors (increases glucose secretion via urine and carry risk of diabetic ketoacidosis)
- Canagliflozin (Invokana)
- Dapagliflozin (Forxiga)
- Empagliflozin (Jardiance)
One of the main benefits of intermittent fasting is that it can improve your overall health.
How does not eating improve your health? Fasting is antiinflammatory and reducing inflammation is key when it comes to avoiding chronic disease.
When you’re fasting, your body goes through autophagy. What is autophagy?
Autophagy means “self-eating.” When your body isn’t focused on digesting and processing food, it’s able to remove or “eat” waste products and damaged, dysfunctional cells. The good parts of these cells are then reused and recycled to create new healthy cells.
Cleaning up waste helps to reduce inflammation.
As mentioned above, lowering blood sugars and insulin also reduces inflammation. Better blood sugar control means improving or helping to prevent diabetes. Anything you can do to lower your risk of chronic disease is beneficial to health.
Intermittent fasting also preserves your lean muscle mass. Short term fasting is not going to cause you to lose your muscle, especially if you’re prioritizing eating protein during your eating window.
If you were to consistently do longer fasts, then you would likely start to see some loss of muscle tissue.
Maintaining your lean muscle mass as you age is one of the major indicators of longevity.
Research is showing many benefits to intermittent fasting. It can lead to weight loss, lower blood sugars, and improve overall health.
When you first start fasting, take it slow. Start with an overnight 12-hour fast and gradually increase your fasting time over several weeks.
What you eat during your eating window is key to reaching your health goals. Prioritize protein intake and make sure you aren’t grazing during your eating period. Aim for eating two to three times.
Be sure to check with your doctor before starting a fasting regimen.