It’s every dieter’s dream: imagine being able to eat whatever you want most days of the week, limiting your intake for one or two days at a time and still losing weight. Believe it or not, intermittent fasting benefits more than just your waistline; crucially, fasting helps to stabilize blood sugar levels, reduce inflammation and keep your heart healthy.
There are a variety of approaches to intermittent fasting and many studies backing the multitude of benefits to your health and overall wellness.
From fasting for just a few hours each day to skipping meals for two days each week, intermittent fasting (IMF) can be an easy way to simultaneously improve your health and achieve your weight loss goals.
What Is Intermittent Fasting?
Intermittent fasting, also known as cyclic fasting, has risen in popularity in recent years as more and more research emerges discovering new intermittent fasting benefits.
In a 2016 Cell Metabolism study called “Fasting, Circadian Rhythms, and Time-Restricted Feeding in Healthy Lifespan,” the authors discuss how fasting allow humans to rely less on our glucose stores for energy and instead on our ketone bodies and fat stories. As a result, “both intermittent and periodic fasting result in benefits ranging from prevention to the enhanced treatment of diseases.” (1) Even fasting mimicking diets (FMDs), which is not true fasting, can create beneficial changes similar to those caused by fasting.
However, intermittent fasting is hardly a new concept. It’s been used for centuries during times when food was scarce and it even plays a central role in many major religions. In fact, once a year, Muslims observe Ramadan, a month of fasting from dawn until sunset.
It’s difficult to define intermittent fasting as there’s not just one correct method for how to fast. In fact, there are many different variations of intermittent fasting that are used around the world. Each follows a different eating pattern that is often strictly adhered to in order to achieve physical or even spiritual results.
How does it work? The extensive research on the concept of intermittent fasting suggests it functions in two different ways to improve various facets of health. First, intermittent fasting results in lowered levels of oxidative stress to cells throughout the body.
The most common types of intermittent fasting — or fasting diets, as some call them — include:
- Alternate-Day Fasting: This entails eating only every other day. On fasting days, some eat no food at all and others eat a very small amount, typically around 500 calories. On non-fasting calorie days, eat normally (but healthfully!)
- The Warrior Diet: This diet involves eating only fruits and vegetables during the day and then eating one large meal at night.
- 16/8 Fasting (also often referred to as Time-Restricted Feeding): For this method, you fast for 16 hours everyday and limit your eating to eight hours. Most often, this simply involves not eating anything after dinner and skipping breakfast the next morning.
- Eat-Stop-Eat: Pick one or two days out of the week and fast for 24 hours, eating nothing from dinner one day until dinner the next day. On the other days, you should have normal calorie days.
- 5:2 Diet: For five days of the week, you eat normally. For the remaining two fast days, you should restrict your caloric intake to between 500–600 calories everyday.
6 Benefits of Intermittent Fasting
1. Promotes Weight Loss
One of the major intermittent fasting benefits is its ability to rev up fat burning and help the pounds slide off. In fact, many people prefer intermittent fasting to traditional diets because it doesn’t require you to meticulously measure your foods and track the calories and grams consumed.
IMF results in increased fat burning and fast weight loss by forcing your body to use up fat stores as fuel. When you eat, your body uses glucose (sugar) as its primary source of energy and stores whatever is left over as glycogen in your muscles and liver.
When you don’t give your body a steady stream of glucose, it begins breaking down the glycogen to use as fuel. After the glycogen has been depleted, your body seeks out alternative sources of energy, such as fat cells, which it then breaks down to help power your body.
This is similar to the ketogenic diet, in which you deprive your body of carbohydrates and force it to use up stored fat for energy.
A 2015 review looked at the effects of alternate-day fasting on body composition and found that, on average, it slashed body weight by up to 7 percent and cut body fat by up to 12 pounds. Whole-day fasting led to similar results, but with up to a 9 percent reduction in body weight. (4) It’s less clear what whole-day fasting does to your valuable muscle stores.
Another study focused on the 16/8 method of intermittent fasting showed that it significantly reduced fat mass while retaining both muscle mass and strength. (5) This fact is why I recommend this style of intermittent fasting the most.
2. Improves Blood Sugar
When you eat, carbohydrates are broken down into glucose (sugar) in your bloodstream. A hormone called insulin is responsible for transporting the glucose out of the bloodstream and into the cells where it can be used up as energy.
Insulin doesn’t always work effectively when you have diabetes, which can result in high blood sugar levels coupled with symptoms like fatigue, thirst and frequent urination.
Some studies have found that intermittent fasting benefits your blood sugar levels by keeping them well-regulated and preventing spikes and crashes.
In one study, participants with diabetes fasted an average of 16 hours daily for two weeks. Not only did intermittent fasting cause weight loss and a decrease in caloric intake, but it also helped significantly reduce blood sugar levels. (6)