16/8 Intermittent Fasting: Meal Plan, Benefits & How It Works In 2024

Intermittent fasting — also known as IF — has been practiced for centuries for religious and spiritual purposes. In recent years, research has shed light on the potential health benefits of intermittent fasting. Studies suggest that intermittent fasting can improve cognitive functions, heart health, and physical performance. It may also protect against diabetes and inflammatory diseases.^[1] Its anti-obesity strategy, when successful, prevents/improves metabolic syndrome. It also corrects the gut microbiome,^[2] a subject becoming more important to the total health of the individual. 

In short, intermittent fasting refers to an eating style that rotates between periods of fasting and eating. Depending on the method of intermittent fasting you follow, you may abstain from food for a certain number of hours or fast for several days at a time. 

One of the most popular styles of fasting is called 16/8 intermittent fasting. It involves fasting for 16 hours a day and consuming all of your calories during an eight-hour eating window.

In this 16/8 intermittent fasting guide, we’ll be discussing its potential benefits and possible risks to help you decide if it is right for you.

What Is 16/8 Intermittent Fasting?

Intermittent fasting (IF) is a form of time-restricted eating that involves fasting for 16 hours and eating during the other eight hours in a day. 

During periods of fasting, you are only allowed water and other zero-calorie beverages such as black coffee and green tea. During the eight-hour window, you consume all of your daily calories. 

This pattern can be repeated as frequently as you would like. Some people practice it daily, while others only practice it a few days per week.

Unlike many other diets that restrict food or food groups, IF has no dietary restrictions and is not centered around counting calories. As long as you fast for 16 hours, you can eat freely during your eight-hour eating period.

How Does Intermittent Fasting 16/8 Work?

Most people do 16/8 intermittent fasting by beginning their fast overnight and skipping breakfast. They often start their first meal of the day around lunchtime.

Intermittent fasting works by extending the length of time your body burns fat after you’ve burned through all the calories (up to and including your last meal).

The theory is that after a person has gone hours without food, their body has used up all of its sugar stores and starts to burn fat. This process is referred to as “metabolic switching.”

Additionally, when the body is without food for an extended period of time, insulin levels^[3] begin to drop. Insulin levels do more than simply react to sugar; they are part of a complicated system that involves liver metabolism of fat, appetite, and other fat-related processes. This can accelerate fat burning.

16/8 Intermittent Fasting Meal Plan

To begin 16/8 fasting, you will first want to choose an 8-hour time window that best fits your lifestyle. This can be an important consideration for those working unusual shifts. Most people find it easier to choose a 16-hour fasting schedule where most of the fasting takes place during rest periods.

Here’s a look at the eating windows of a few of the most popular 16/8 intermittent fasting schedules:

• 2 p.m. to 10 p.m.
• 9 a.m. to 5 p.m.
• 12 p.m. to 8 p.m.
• 7 a.m. to 3 p.m.

One of the most common time windows involves eating from noon to 8 p.m. and fasting from 8 p.m. to noon the following day. This is because many people prefer to skip breakfast and enjoy lunch and dinner, with snacks throughout the day.

However, athletes or those who tend to wake up in the morning for intense workouts often require a meal beforehand to avoid reducing their training performance or running low on the energy needed for such exertion. In this case, a fasting plan with an eating window between 7 a.m. to 3 p.m. may be more beneficial.

It’s also important to space your meals out during the time window of your choice to promote blood sugar control and satiety.

Recommended Foods

Although it is not required, some people choose to follow diets such as the paleo diet or keto diet combined with intermittent fasting. However, it isn’t always necessary. 

One of the best ways to maximize your health benefits and prevent overeating or weight gain when practicing intermittent fasting is to eat a well-balanced diet and follow a healthy meal plan. If your food intake during your eating window is filled with high-calorie, unhealthful foods, it could cause you to gain weight. In other words, you still have to “eat right.”

Ensure your healthy diet contains the following foods to promote your overall health:

• Lean protein (chicken breast, lean beef, beans, eggs, legumes)
• Whole grains (brown rice, quinoa, oats, barley)
• Fresh or frozen fruits (apples, berries, mango, etc.)
• Vegetables (green beans, broccoli, asparagus, brussels sprouts, spinach)
• Healthy fats (salmon, olive oil, avocados, nuts, and seeds)

Be sure to stay adequately hydrated throughout the day to avoid a false sense of hunger. It is felt that food intake may be regulated less by hunger than by satiety, so besides adequate hydration assisting kidney health, having something in your stomach, even liquids can be an important strategy in IF.

Benefits of 16/8 Intermittent Fasting

As we learn more about IF, scientific studies suggest fasting can do more than merely help those who follow the eating plan to lose weight. 

Here, we’ll discuss the research-backed benefits of 16/8 intermittent fasting.

Weight Loss

If you are following a well-balanced diet, limiting your eating window to eight hours a day will reduce overall calorie intake and, over time, 16/8 intermittent fasting results in a reduction of body weight.

One 2020 review published in Canadian Family Physician^[4]looked at a total of 27 trials to examine the effectiveness of IF in promoting weight reduction.

All 27 trials found that participants lost between 0.8% and 13.0% of their baseline weight. What’s more, five of the studies included participants with type 2 diabetes who also experienced improved blood sugar control. No serious side effects were reported during any of the studies.

Another review of studies published in the Journal of Nutrition and Dietetics^[5]suggests that IF can result in weight loss regardless of the method of fasting chosen. Out of 13 studies included in the review, 11 reported significant weight loss among participants.

Fat Loss

Aside from lessening caloric intake, IF may also help promote fat loss by boosting metabolism. In one study from 2017 published in the International Journal of Obesity^[6], researchers found that obese men who practiced intermittent fasting lost more fat and weight compared to those who did not.

Additionally, one 2016 study^[7] found that men who paired resistance training with 16/8 intermittent fasting for eight weeks experienced a decrease in fat mass. The conclusions were also noteworthy for finding that the participants did not lose any muscle mass throughout the study period.

Reducing Inflammation

A newer 2019 study^[8] suggests that intermittent fasting can reduce oxidative stress and lower levels of inflammation throughout the body.

Many diseases are associated with chronic inflammation. These include:

• Alzheimer’s
• Cancer
• Heart disease and Type 2 diabetes
• Crohn’s, ulcerative colitis, and other bowel diseases
• Rheumatoid arthritis

Disease Prevention

Some studies suggest intermittent fasting can also protect against chronic health conditions. One 2014 review published in the Journal of Laboratory and Clinical Medicine^[9] found that IF can be a useful alternative to calorie restriction for weight loss and in reducing the risk of type 2 diabetes in overweight and obese individuals.

Another 2020 study published in the European Journal of Preventive Cardiology^[10] found that intermittent fasting was linked to a lower risk of developing heart failure and a longer lifespan.

We were never designed to “work well” with obesity. Whether all of these preventative benefits are a result of the metabolic shifts that the “intermittent” part of IF relies upon or just losing weight successfully, no one really knows. At the end of the day, however, what’s the difference?

Potential Risk Factors & Side Effects

There are many different reasons a person may try intermittent fasting. For example, some people may try it to lose weight, while others may fast to improve their overall health. The reality is that they’re doing both!

Even though IF has many potential health benefits, it is not for everyone. Always consult with your healthcare provider before making any dietary changes to discuss the potential risks and side effects of intermittent fasting.

When you first start fasting, you may experience hunger, irritability, and weakness. However, once your body adjusts to your new eating patterns, it typically subsides. The human body is surprisingly adaptive to new ways to “live.”

Although many studies highlight the weight loss benefits associated with intermittent fasting, it may have adverse effects for some. If you know you are only allowed an 8-hour window to eat each day, you may overeat to avoid feeling hungry during your fasting period. This can cause weight gain, an upset stomach, and disordered eating habits.

Moreover, according to the National Eating Disorders Association, a fixation on fasting has the potential to lead to disordered eating. Those who are at risk or have a history of an eating disorder should avoid fasting unless otherwise instructed and managed by their dietitian or healthcare provider.

The National Institute on Aging^[11] also suggests that, due to the lack of evidence, we need to learn more about the safety and effectiveness of fasting diets and diets that promote calorie restriction, especially in older individuals. (The calories stay the same calories over our lifetime, but we change.)

Populations who should avoid intermittent fasting unless otherwise instructed by their healthcare provider include the following unique groups:

• Pregnant and lactating individuals
• Those with low blood pressure, diabetes, or blood sugar problems (risk for hypoglycemia)^[12]
• Children and teens under the age of 18
• People with a history of mental health disorders
• Individuals with a history of eating disorders

Is 16/8 Intermittent Fasting Right For You?

16/8 intermittent fasting is one of the most popular types of fasting today. It is a time-restricted eating pattern in which a person fasts during a 16-hour time window and eats normally during the remaining 8 hours.

In addition to losing weight, some studies suggest 16/8 IF can help promote blood sugar control, promote fat loss, reduce inflammation, and prevent diabetes and other chronic diseases. Pair healthy eating and a well-balanced diet plan for best results. 

It’s important to note that IF is not for everyone. Pregnant and lactating individuals, those with a history of eating disorders, and people with certain health conditions should avoid IF. 

As always, you should consult with your healthcare provider and/or registered dietitian before making any dietary changes.

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