Intermittent Fasting-Is it for You?
Have you heard about Intermittent Fasting (IF)? Some people swear by this method as a means to help them lose weight or improve blood sugars. Others find there are complicated rules they have trouble following. The research on IF for weight loss is promising, but mixed. However, there are other reasons to consider IF. Before you decide if it's for you, let's explore what it really is and who may benefit.
What is intermittent fasting?
There really isn’t anything new about intermittent fasting. Intermittent fasting is a fancy term for not eating any food between your last meal of the evening and your first meal of the morning. In other words, after you eat dinner, don’t eat again until breakfast…which literally translates into break (the) fast. Breakfast is the meal we have every morning to break our overnight fast. The problem for many people-they don't have an adequate fast between dinner and breakfast. As it also turns out, many people who skip morning breakfast due to lack of hunger find they are plenty hungry in the morning when they don't eat late at night!
Minimally, most people can benefit from a 12-hour fast. This can easily be accomplished by following the simple advice of no food between tonight's dinner and tomorrow's breakfast. So, if you finish your evening meal at 7:00 p.m. (and don’t have an evening snack), you should try to wait until 7:00 a.m. the next day before eating breakfast.
A 12-hour fast is adequate for your body to fully digest the meal you had in the evening as well as maintain stable blood sugars upon awakening and starting your day. Avoiding after dinner snacking has a few benefits. First, you're less likely to consume extra calories your body doesn't need. Secondly, avoiding snacking before bed can help improve your quality of sleep. Going to bed on a full stomach is never recommended. If you tend to have your meals later in the evening, it's a good idea to make sure you finish your meal at least two hours before going to bed.
While a 12-hour fast is a pretty good idea for just about everyone, most IF regimens call for a longer fasting period than 12 hours. The most common IF regimen calls for a 16-hour fast.
Is fasting for 16 hours better than fasting for 12 hours?
Maybe…or maybe not. There really isn't any solid evidence to suggest that a 16-hour fast is better than 12-hour fast. A 16-hour fast usually translates into two meals per day, while a 12-hour fast has enough room for three meals.
For some people, eating two meals per day makes it easier to decrease total caloric intake, which is a key element to weight loss that may result from IF. This is where it's important to be mindful of the fact that IF regimens have two important features:
1. A defined eating window.
For some people, having a structured eating window helps draw a line in the sand on when they “can’t” have any more food. This may be particularly helpful for people with the habit of late-night snacking or snacking out of boredom rather than hunger.
2. A calorie limit.
While many people interested in intermittent fasting are hoping to lose weight, it’s important to understand that calories, and quality of calories, still count. In other words, there is nothing magical about intermittent fasting that suggests you can “pig out” as long as you are doing so in your defined eating window.
What are some typical IF regimens?
You may have heard of “16/8.” This means 16 hours of fasting and an 8-hour eating window. This typically translates to two meals, which could be a later than usual breakfast and and evening meal, or a lunch and evening meal. For example, an eating window of 10:00 a.m. – 6:00 p.m. or 11:00 a.m. – 7:00 p.m. For super early risers, it may mean an earlier breakfast and a late lunch.
Another regimen is known as the "5/2." This calls for intermitting fasting for 5 days interspersed with two days of very low calorie days or complete fasting. This is a little more difficult for some people and may not be advised for certain medical conditions.
Easing your way into IF
A 12-hour fast is a great place to start. This may be as simple as not eating after dinner, which can provide tremendous health benefits. This may be just the small tweak you need to make big health gains. If you decide to experiment with other types of regimens, this is best done in collaboration with a registered dietitian nutritionist (RDN). Your RDN can counsel you on appropriate number of calories for your age and other lifestyle factors, as well as provide guidance on food selection based on any medical conditions that need to be considered.
At the end of the day, it’s important to realize that calories still count. If weight loss is your main reason for trying IF, be patient, as your desired results will not happen overnight. Instead of strictly focusing on a number on the scale, be mindful of other benefits such as improved quality of bedtime rest, improved lipids or blood sugars, and overall feeling of well-being you may experience.
Dr. Amy Knoblock-Hahn is a registered dietitian nutritionist and health behavior expert specializing in both chronic disease and weight management.