Should You Do 18:6 Intermittent Fasting?

Intermittent fasting is a hot topic in health and fitness. Some people swear by it, while others are skeptical of its benefits. In this blog post we will talk about one particular form of intermittent fasting called the 18:6 plan, what it is, and if it is right for you.

What is the 18:6 intermittent fasting plan?

As a registered dietitian, one of the most common questions I get asked is ‘should I follow an intermittent fasting diet?’ But what most people don’t realize is that ‘intermittent fasting’ is an umbrella term and can refer to many different styles of eating – from time restricted eating to alternate day fasting.

In this article, I’ll be discussing the form of time restricted eating called the 18:6 plan, which is one of the most popular forms of intermittent fasting, or IF. The idea behind it is that you fast for 18 hours a day and only eat during a six hour window. For example, if your last meal was at dinner time (around six o’clock) then you wouldn’t eat again for 18 hours, or until 12pm the following day.

With the 18:6 style of time restricted eating, you would eat during the same eating window each day, so you want to be sure the six-hour eating window you choose works for your lifestyle. Many people choose to have a later eating window, eating their daily calories from 12pm-6pm or from 2pm-8pm. However, some research suggests an earlier eating window may offer additional metabolic and health benefits.

A sample meal plan for 18:6 intermittent fasting

With time restricted eating, there are no specific calorie or macronutrient goals. The idea is to consume your nutrition and energy needs during a small eating window and fast the remainder of the day. Which means there is no need to track or count calories or macros, a factor that can be appealing to some people.

For someone who chooses to fast for 18 hours starting at 8pm each night, a sample meal plan timeline may look like this:

2pm: First meal of the day

4pm: Snack

6pm: Meal

7:30pm: Last meal or snack of the day

Food choices, calories, and macronutrient composition can vary from person to person depending on their needs. What doesn’t change is the eating window timeframe or length from day to day.

Does the 18:6 intermittent fasting plan promote weight loss?

Studies have shown intermittent fasting has been shown to promote weight loss and may offer some health benefits, such as improvements in sleep quality as well as improved insulin sensitivity. 

Although more research is needed, IF appears to provide similar weight loss benefits to following calorie restricted meal plans. For some individuals who would prefer to simplify their weight loss approach by only focusing on eating time versus following a structured calorie controlled eating plan every day, this style of eating may be a good match for weight loss success.

When you choose to eat can impact the benefits of this plan as well. Some research suggests that early time restricted eating – where the eating window is earlier in the day versus later – may be better for appetite regulation as well as metabolic benefits such as improved insulin sensitivity.

What are the benefits of following an 18:6 plan?

There are many potential benefits to following this style of intermittent fasting, including:

– Eating during a smaller window each day may help with appetite regulation and food cravings

– Anecdotally this plan has been reported as being easier for some people to follow versus daily calorie restricted eating or fasts that restrict the entire day. This is likely due to the fact that there is less focus on what you should or should not eat during your eating window, rather it being more about when you should be eating.

– Some people may find this easier for social situations where food intake can vary from day to day since they are only needing to worry about their daily nutritional needs within a set time.

It is easier to plan ahead of time for this style of intermittent fasting since you know exactly when your eating window starts and ends each day versus following a different meal schedule on different days

Cons of the 18:6 intermittent fasting plan

There are also some potential drawbacks associated with the 18:6 approach, including:

– With a focus only on food timing and not on actual food consumption, it is possible to fall short on nutrient and energy needs. Care should be taken to ensure you still consume your total daily needs for vitamins, minerals, fats and carbohydrates each day.

– This plan may not work well for everyone due to social situations where it is difficult to control food intake or travel that could interfere with the ability to eat at your chosen time window.

– IF is a restrictive meal plan and may be triggering by some individuals with a history of disordered eating. For those individuals, any form of IF is discouraged.

-The human studies to date on time restricted eating, and specifically on an 18:6 meal plan, are limited. More research needs to be done to truly understand the potential health benefits (and any downsides) this eating style may offer.

Should you do 18:6 intermittent fasting?

Should you choose the 18:6 plan over alternate day fasting, calorie restriction, or one of the many other weight loss strategies available? The answer is it depends. The 18:6 plan works well for some lifestyles, personalities, and goals, but not all.

If you’re looking for a way to simplify your nutrition approach while still achieving all of the benefits of intermittent fasting (such as appetite control, weight loss, and better sleep), the 18:6 plan may be a good option for you.

However, eating during a short 6-hour window doesn’t work for everything. If you have a history of disordered eating, I would avoid following any form of IF as the restrictive nature of it could be triggering.

If you have diabetes and uncontrolled blood sugar levels, eating during such as short window of time may increase the risk of hypoglycemia and should be avoided. Additionally, individuals with certain health conditions, and those who are pregnant or breastfeeding should also avoid this style of eating.

Individuals who are very physically active may not find time restricted eating works for their increased energy needs. If you are an athlete or a very physically active person considering an 18:6 plan, you will need to ensure your eating window matches with exercise routine to be able to fuel your body both before and after a workout.  

The bottom line on intermittent fasting

The bottom line is that there’s no one size fits all approach to intermittent fasting or eating in general. The meal plan you choose to follow should fit into your lifestyle, health needs, and goals.

Remember, in order to improve health or body weight, you need to be consistent. If you cannot follow an 18:6 plan consistently, you won’t achieve the benefits from it.

As with any diet plan, always consult your physician and medical team before starting or changing any meal plan to ensure it is right for you.