Forms of intermittent fasting exist in religious practices in various groups across the world. Religious fasting regimens include, but are not limited to, Vrata in Hinduism, Ramadan fasting (Islam), Yom Kippur fasting (Judaism), Orthodox Christian fasting, Fast Sunday (The Church of Jesus Christ of Latter-day Saints), and Buddhist fasting. Certain religious fasting practices, like Buddhist fasting, only require abstinence from certain foods, while others, like the Jewish fast on Yom Kippur, last for a short period of time and would cause negligible effects on the body.
An intermittent fast is a brief fast where, for 12–16 hours or more, you don’t eat anything except water (a few exceptions apply). And while that may sound incredibly difficult to achieve, you might already be fasting without knowing it if you eat dinner at, say, 7 p.m. and break your fast in the morning between 7—10 a.m. — and if you only have water and black coffee or tea between.
How It Works: Not completely satisfied with the IF diets listed above? This method takes the best parts of Eat Stop Eat, The Warrior Diet and Leangains, and combines it all into one plan. You also get one cheat day each week (yay!) — followed by a 36-hour fast (which may be not-so-yay for some). After that, the remainder of the seven-day cycle is split up between the different fasting protocols.
There are different types of intermittent fasting, but the most common involves only eating within a certain window of time each day. For example, you might only eat between 12pm and 6pm each day, giving you a 6-hour “feeding” window when you eat all of your calories for the day. That means you’ll be fasting for 18 hours in between. Your intermittent fasting ratio would then be 18/6.
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.
Cons: Going 24 hours without any calories may be too difficult for some — especially at first. Many people struggle with going extended periods of time with no food, citing annoying symptoms including headaches, fatigue, or feeling cranky or anxious (though these side effects can dimish over time). The long fasting period can also make it more tempting to binge after a fast. This can be easily fixed… but it takes a lot of self-control, which some people lack.
On this plan you'll eat clean five days of the week but will not eat anything for two nonconsecutive days of the week. 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.
With this information in hand, you should know exactly how to schedule meals when starting an intermittent fasting plan. And while it might seem complicated at first, once you get into the habit of fasting, it will feel like second nature and fit pretty seamlessly into your days. Just remember to always start slow and gradually work up to more advanced plans.
Of course, most people use IF with another weight-loss plan. For instance, you might decide to eat 1,200 calories a day to lose weight. You may find it much easier to spread out 1,200 calories within two meals and two snacks than in three meals and three snacks. If you’ve struggled with weight loss because your diet either didn’t work or was simply too hard to stick to, you might try intermittent fasting for quicker results.
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 time restricted chunks of the day, you’ll be eating less food, which eliminates a lot of the stress around having to meal prep. During the periods of time in which you're 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! Here are some of the effects of intermittent fasting:
In one study, protein and carbohydrates were more efficiently absorbed in individuals who completed a cardio workout after fasting, as opposed to those who consumed a carbohydrate rich breakfast prior to working out. This research indicates that fasting can assist your body to more efficiently absorb nutrients from your post-exercise meals, as well as improve your general health and boost lean muscle mass growth.
The four-hour eating window — which Hofmekler refers to as the “overeating” phase — is at night in order to maximize the Parasympathetic Nervous System’s ability to help the body recuperate, promoting calm, relaxation and digestion, while also allowing the body to use the nutrients consumed for repair and growth. Eating at night may also help the body produce hormones and burn fat during the day, according to Hofmekler. During these four hours, the order in which you eat specific food groups matters, too. Hofmelker says to start with veggies, protein and fat. After finishing those groups, only if you are still hungry should you tack on some carbohydrates.
Because it simplifies your day. Rather than having to prepare, pack, eat, and time your meals every 2-3 hours, you simply skip a meal or two and only worry about eating food in your eating window. It’s one less decision you have to make every day. It could allow you to enjoy bigger portioned meals (thus making your tastebuds and stomach satiated) and STILL eat fewer calories on average.