What Is Alternate-Day Fasting? Your Simple Guide to Extreme Intermittent Fasting Schedule

Alternate day fasting for females and males is a special eating plan where you eat a normal diet one day, and either completely fast or eat a small amount of food (no more than 500 calories) the next day (2).

Some people go on this eating plan for mostly weight-loss purposes. But is this fasting regime effective for weight loss? And how much weight will you lose if you try it? You’ll get all these answers covered as we’re going to learn what alternate-day fasting is. Here’s your simple guide to extreme intermittent fasting schedules. 

How Many Hours Is Alternate-Day Fasting?

Alternate-day fasting involves around 36 hours of fasting. Some people don’t eat at all during this time, but most versions of this fasting regime include some food on fasting days, up to 500 or 600 calories, or 25% of usual energy needs.

It’s important to keep well-hydrated during the 36 hours. In addition to water, you’re also allowed to consume:

1. Unsweetened coffee
2. Unsweetened tea
3. Sparkling water
4. Any other beverage without calories

What Is an Example of Alternate-Day Fasting?

 The alternate-day fasting schedule is quite simple to remember. Here’s how it looks:

• Day 1: Eat as usual to satisfy your hunger
• Day 2: Fast, either eating nothing except calorie-free beverages, or eating a small amount of food up to 25% of your calorie needs or 500 calories
• Day 3: Eat normally
• Day 4: Fast as on day 2 

Despite being more extreme, this alternate-day fasting schedule is easier to understand, but is certainly more challenging to undergo. Please note that beginners should avoid this fasting regime and begin with simpler versions. Examples of milder intermittent fasting regimens include: 

• Fasting for 12 hours a day
• Fasting for 14 hours
• Fasting for 16 hours

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How Much Weight Can You Lose Doing Alternate-Day Fasting?

Now we’ve come to the juiciest part of this article: is alternate fasting a good option for weight loss and if yes, how much weight can you expect to lose with it? 

We’ll start with the first question and the answer may not completely satiate you as there are controversial opinions regarding weight loss through intermittent fasting. 

One 2023 meta-analysis compared alternate-day fasting, the 5:2 diet, and time-restricted eating, in addition to traditional calorie restriction. It concluded that intermittent fasting in general is comparable to traditional energy restriction as a weight loss tool, and that of the 3 types of intermittent fasting regimes, alternate-day fasting was the most effective for weight loss (3).

At the same time, a longer randomized clinical trial with 100 metabolically healthy obese adults concluded that an alternate-day fasting regime didn’t result in superior weight maintenance or weight loss compared to daily calorie restriction (4).

At six months, both the calorie-restricted and alternate-day fasting groups had lost 6.8 percent of their weight. By one year, the fasting group reduced weight to 6 percent, and the calorie restriction group 5.3 percent. 

In addition, the alternate-day fasting group showed the highest dropout rate: 38 percent stopped the study, compared with 29 percent of the calorie restriction group.

To summarize, research has shown the efficacy of alternate-day fasting on weight loss, but it’s not significantly better than calorie restriction. Therefore, alternate-day fasting may not be for everyone. There are other factors that will affect your weight results during alternate-day fasting for 1 week and longer: 

• Food choices on non-fasting days
• Sleep quality
• Lifestyle and activity level
• Stress levels

As is widely known, healthy weight can’t be simplified to just what you eat, and it’s about many of the daily choices you make. 

Read more: What to Eat After Fasting and What to Avoid to Reap the Benefits

How Much Weight Will I Lose on a 3-Day Water Fast?

How much weight will be lost by fasting for 3 days will vary from person to person, but most of this weight will be due to water loss. The fluid and the weight will return once you start eating again (5).

If you want to lose actual weight in a healthy and sustainable way (and you can), here are a few effective tips for you: 

• Burn more calories than you consume daily
• Avoid highly processed sugary foods and beverages
• Eliminate alcohol intake, or at least reduce it
• Sleep at least 7 hours per day
• Track your stress levels, ensuring you manage it in a healthy way
• Eat more fruits, vegetables, whole grains, berries, legumes, beans, eggs, lean meat, fish, and nuts (this will do your body a huge favor)
• Get physically active, making sure to include cardio workouts, resistance training, and any other form of exercise you enjoy. 

Is it Good to Fast on Alternate Days?

According to sources, there may be some alternate-day fasting benefits:

Alternate-Day Fasting May Help People with Type 2 Diabetes

According to one study, similarly to continuous calorie restriction, an alternate-day fasting regime may help reduce some of the risk factors for type 2 diabetes and people with overweight or obesity (6).

Alternate-Day Fasting May Benefit Better Body Composition

Studies have found that alternate-day fasting can produce similar or better weight loss results compared to other forms of fasting and traditional calorie restriction (4). This includes reductions in visceral (abdominal) fat (6).

Alternate-Day Fasting May Enhance Your Heart Health

Some studies have suggested that alternate-day fasting may help with weight loss and help reduce some of the risk factors for heart disease (9), (10).

In addition, a study has shown that alternate-day fasting appears to improve blood pressure and insulin sensitivity markers in a similar way to continuous energy restriction (4). Ultimately, weight loss can help improve risk factors for chronic diseases, and it should be noted that weight loss can be achieved in a variety of ways. Everyone needs to determine what works best for them, in consultation with their healthcare provider. 

Read more: 17/7 Intermittent Fasting: A Practical Approach to Time-Restricted Eating

Is Alternate-Day Fasting Safe?

Different research has suggested that an alternate-day eating regime is generally relatively safe for most healthy adults. However, using it as the main remedy for weight loss may not be more effective than calorie restriction.

Certain populations should avoid this eating plan, including: 

• Pregnant and lactating women
• Children
• Underweight people
• People who take insulin 
• Those with a history of eating disorders
• Those with uncontrolled blood sugar issues
• Anemic people
• People who work out hard
• Those who are taking medications that impact blood sugar

Although there may be prolonged fasting benefits, it can clearly be seen that this process is not for everyone. 

This eating schedule may also be too difficult for beginners, as not eating for a whole day can provoke dizziness, fatigue, constipation, and dehydration. You may initially feel hungry and tired and unable to think of anything else but food. 

If you still aim to try it, please make sure that you drink plenty of fluids as hydration is vital, particularly during non-eating periods. 

In addition, if you fast every other day, you may lose some of your muscle mass and experience high stress levels. Some individuals may also delve into junk foods as compensation for the “fasting sacrifices” they made the previous day and some may even turn to binge eating, which is another obstacle that will interfere with your fat-reduction goals. If you experience any negative effects from fasting, try a different weight loss strategy.

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FAQs

• What happens to your body during alternate-day fasting?

During alternate-day fasting, you may feel hungry at first and simply feel tired, dizzy, or fatigued. After alternate-day fasting for 1 month or longer, you may experience less hunger or cravings than in the first week and you may also start to notice changes in your body weight. 

• Does coffee break a fast?

Black coffee contains zero calories, which makes it drinkable during the fasting period. However, if you add milk to it or sugar, then you will break a fast. 

• What can I drink while fasting?

During fasting, you can drink still or sparkling water, unsweetened coffee and tea, and other zero-calorie beverages.

• What are the results of alternate-day fasting for 3 months?

People who practice alternate-day fasting for 3 months may see changes in their weight. They may also start to experience improvements in insulin sensitivity, blood pressure, or other health markers, particularly if they’ve lost significant weight. However, this will vary for every individual and could take longer to see. 

The Bottom Line

What is alternate-day fasting? Let’s summarize the whole article. Alternate-day fasting is a special eating plan where you eat a normal diet one day, and either completely fast or consume only a small amount of food (no more than 500 calories) the next day. 

This eating schedule involves approximately 36 hours of fasting. During this time, you need to drink a lot of water and are allowed to consume unsweetened coffee and tea. 

People can lose weight with alternate-day fasting, but this fasting regime has not proven to be more effective than calorie restriction. 

Alternate-day fasting offers a range of possible benefits: better insulin sensitivity, weight loss, improved blood pressure, and more. Despite being relatively safe, some individuals should avoid this day-alternating eating plan. You should talk to your doctor before you start any intermittent fasting regime if you have any health conditions or are taking certain medications.