Registered dietitian Jessica Bippen, MS, RD, gives us the rundown on what you need to know about intermittent fasting before you skip meals.
Remember when breakfast was the most important meal of the day? In fact, new research is showing there may be benefits from skipping your overnight oats and avocado toast in the a.m. Intermittent fasting is becoming increasingly popular, but it’s actually not a new concept at all. Back in hunter-gatherer times, meals weren’t always guaranteed. Chinese Medicine and Ayurveda practices encourage regular fasts as a way to provide mental clarity and overall wellness. Finally, fasting is often observed in various religions for various spiritual and physical benefits.
What is intermittent fasting?
Intermittent fasting is by definition a brief time period during which you refrain from eating or drinking. It permits a few exceptions like water, tea, coffee, and bone broth. Intermittent fasting shouldn’t be confused with starvation or calorie restriction. It’s simply shorting your time window of eating.
It might be helpful to think of intermittent fasting as an eating pattern rather than a diet. With food easily accessible, we’ve been programmed to eat anywhere from three-to-six times per day—and that’s if we’re not grazing on trail mix or sipping on a green juice in between meals. Intermittent fasting sets a limited time window of eating so your body can take a break from digestion—which uses a lot of energy!—and instead spend dedicated energy taking care of other processes like cellular repair and fighting oxidative stress.
What are the benefits?
Intermittent fasting enthusiasts claim numerous benefits from increased energy and mental clarity to reducing disease risk and aiding in weight loss. While this trendy eating pattern may seem too good to be true, there’s research to support the benefits.
Some of the latest evidence-based benefits on intermittent fasting include:
- Reducing inflammation
- Lowering total cholesterol, LDL cholesterol, blood triglycerides, and blood pressure
- Managing blood sugar by normalizing insulin sensitivity
- Weight loss from decreased calorie intake and temporary increase in resting energy expenditure
- Improvements in degenerative brain disorders
- Lowering inflammation in the gut
Intermittent Fasting MEthods
While there are several different ways to fast, there isn’t research to support a superior way. The key—as with any new routine—is consistency. Below are some of the most popular methods of intermittent fasting. Some methods are more extreme than others.
In this broad fasting scenario, you abstain from food for 12 to 16 hours. In the most popular version, you fast for 16 hours and have an eight-hour window of eating in a 24-hour time period. For example, you stop eating at 8 p.m. and eat your first meal around noon the following day.
This eating plan allows for five days of normal eating and two non-consecutive days of eating only 500 to 600 calories per day.
In this plan, you go an entire 24 hours without eating two or three times per week.
Are there negative side effects?
Some side effects of prolonged fasting include increased stress levels, disrupted sleep, headaches, and moodiness. Hanger is real, people. It’s important to listen to your body. If you feel faint, lightheaded, shaky, or nauseous, you’re better off breaking your fast and eating something.
There’s also the possibility of forming a restriction-bingeing cycle, which is typical with calorie-restricted diets. When individuals feel deprived, they may overeat or binge when “allowed” to eat. It can set individuals up for weight gain and creating a negative relationship.
Intermittent fasting can also be hard on your social life. If you’re committed to the consistency, what happens when you have a brunch celebration? Intermittent fasting can get in the way of life’s many celebrations, which are often centered around meals.
who it might not be for
Most research on intermittent fasting has been done on men, and these results don’t automatically transfer over to women. Women have more complex hormone systems. Research shows that intermittent fasting can cause hormone imbalances and irregular periods in women when not done correctly.
Women who are pregnant or breastfeeding shouldn’t fast. Those who are underweight, have histories of eating disorders, have diabetes or problems with blood-sugar control, suffer from adrenal fatigue and chronic stress, have a medical condition, and take medications should never fast without consulting with a doctor first.
In general, it’s very important to talk with your doctor before making any drastic changes to your diet or exercise program.
Should you be intermittent fasting?
As with any changes you’re making to your diet and lifestyle, it’s important to understand your reasons. For instance, are you looking to break through a weight-loss plateau? Intermittent fasting may help you break through a weight loss plateau, but there are other diet and lifestyle changes that have this benefit as well.
If you don’t have any of the conditions mentioned above and want to give intermittent fasting a try, here are some questions to consider. Is it a sustainable way of eating for you? Does it interfere with your social life? How does it actually make you feel? Do you enjoy it and can you create a lifestyle around it? Different eating patterns work for different people. If you think intermittent fasting is the way to go, I recommend starting out slow with a 12-hour fast once or twice per week.
Just remember: There’s no one-size-fits-all plan when it comes to diet and lifestyle. Intermittent fasting may work for you, and that’s awesome—but don’t feel like you have to adhere to this eating pattern to live a healthy lifestyle.