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24 Hour Fasting Diet - A Beginner's Guide
Updated on September 13, 2023
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Diet / Weight Loss
24 Hour Fasting Diet - A Beginner's Guide
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Intermittent fasting is an eating pattern where you switch between cycles of fasting and feeding. 

You’re not starving yourself with this eating routine. It is actually a form of calorie restriction

But instead of limiting the types of food you can eat, it gives you a smaller eating window to better control your calorie intake.1 

You’re not supposed to eat or drink certain foods during your fasting period. This forces your body to enter ketosis — a metabolic state where your body starts burning fat stores for energy. 

You can go back to eating normally once you begin your eating window.

24 Hour Fasting Diet - A Beginner's Guide 2

What is a 24 Hour Fast?

The 24-hour fast or eat-stop-eat diet is a type of intermittent fasting schedule. It’s not the same as alternate-day fasting, which involves fasting every other day.

“Intermittent fasting burns the body’s fat stores after not eating for long periods. This is called metabolic switching,” says our in-house expert, Dr. Rizza Mira.

If you try the 24-hour fasting diet, you shouldn’t eat food for 24 hours. Only water and tea are allowed. You can do this once a week or even twice. Other days of the week are for eating normally.

Most people fast from breakfast to breakfast the next day. Others do it from lunch to lunch. 

This schedule allows you to eat only one meal a day. It keeps you from feeling like you haven’t eaten the entire day.

What Can I Eat During a 24-Hour Fast?

During your fast, you shouldn’t eat anything that contains plenty of calories. Sugary drinks and high-calorie beverages such as juice, sodas, and shakes are off the table. 

You can have zero-calorie beverages such as water or very low-calorie drinks like tea and black coffee. 

Using sweeteners or cream will break your fast. Once your fasting window ends, you can go back to eating proper meals.

What to Eat After 24-Hour Fast

After your 24-hour fast, you can eat anything. That doesn’t mean that you should binge eat junk food, however. 

Doctors encourage you to be careful with your eating, especially on your non-fasting days. 

Choose nutritious foods and cut out the empty calories. This allows you to maximize the potential health benefits of intermittent fasting. 

Nutrition experts often recommend the Mediterranean diet as a guide on what healthy foods to choose. This diet includes plant-based foods, such as:2

  • Whole grains like oats, brown rice, and whole wheat bread
  • Vegetables and fruits
  • Legumes, such as beans, peas, and lentils
  • Nuts and seeds like almonds, walnut, and sunflower seeds
  • Herbs and spices like garlic, basil, rosemary

Some people worry that intermittent fasting can make you overeat after the fasting period. Studies show that it’s not more likely to cause binge eating than other weight loss diets.3 

“One of the drawbacks of restrictive diets is rebound weight gain. This is when a person suddenly craves more empty-calorie foods because of their abrupt withdrawal from a person’s system,” says Dr. Mira.

24-Hour Fasting Benefits

Fasting for 24 hours can seem extreme for beginners, as it may take two to four weeks to adjust to this kind of diet. But unlike different types of intermittent fasting, it doesn’t require you to fast every day.

This might be a plus for someone who can’t commit to daily fasting. If you’re considering a 24-hour fast, you should know that it gives you many of the same benefits as other types of fasting:

1. Makes You Lose Weight

Intermittent fasting is proven to help with weight loss. Studies show that people lose an average body weight of seven to 11 pounds over a 10-week fast.3

Some researchers say it’s because fasting restricts your calories and reduces your overall caloric intake. This helps you achieve a calorie deficit, which is essential to weight loss. 

A calorie deficit happens when you eat fewer calories than your body burns. 

Others believe the stress caused by the diet changes your metabolic rate. 

Either way, both can lead to body fat loss and help you achieve weight loss.

2. Lowers Your Diabetes Risk

In type 2 diabetes, your blood glucose levels rise due to your body’s insulin resistance. 

Intermittent fasting can improve insulin sensitivity for better blood sugar control. It also helps prevent you from developing diabetes.

Diabetes is marked by insulin resistance, which means your body needs higher insulin levels to control your blood sugar levels. Fasting helps lower your risk of diabetes by decreasing your insulin resistance.4 

If you have diabetes, you must speak with your doctor before trying intermittent fasting. 

“Prolonged fasting can lead to the dangers of hypoglycemia, low blood sugar, coma, weakening of the heart, or even death,” says Dr. Mira.

Doing this will help you safely enjoy its benefits. 

3. Protects Your Heart 

Intermittent fasting can protect you from cardiovascular diseases by regulating your risk factors, such as:5

  • Blood sugar levels
  • Blood pressure
  • Blood triglycerides
  • Total and LDL cholesterol

Triglycerides are a type of fat (lipid) in your blood. High levels of it put you at risk for heart disease.

Low-density lipoproteins (LDL) are an unhealthy kind of cholesterol. Elevated LDL cholesterol levels are bad for your heart health. 

4. Reduces Inflammation 

Many chronic diseases are linked to inflammation and oxidative stress. This can happen when toxins accumulate in your body due to metabolism. 

These toxins damage essential cell structures, such as proteins and DNA.6

Intermittent fasting helps decrease the body’s inflammation by decreasing the number of cells that cause it.

Further studies show that these cells become inactive and less inflammatory during fasting periods. Fasting lowers your risk of developing chronic inflammation, which causes many diseases, including heart disease and diabetes, arthritis, and inflammatory bowel diseases.7

5. Promotes Cell Repair 

The body needs to remove and replace cell structures that are old and worn out with new cells. Intermittent fasting helps with this process. 

“Fasting causes a drop in insulin, an increase in growth factors– this process helps repair damaged cells,” says Dr. Mira. 

During the fasting period, your body may enter ketosis — a state where it turns stored fats into energy. This stage triggers autophagy.

Autophagy is when our body eliminates waste and breaks down damaged cells and proteins.8 

Removing these materials from your body also protects your health.

6. It Improves Your Brain Health 

Intermittent fasting slows aging by reducing the damaging effects of free radicals. Your body becomes better at resisting diseases. It also helps boost your brain functions since intermittent fasting helps regenerate and produce new and healthy nerve cells.

During a fast, your body undergoes ketosis and starts burning fat. The burned fat is converted to ketones and used for energy instead of sugar.

This change in energy source fights brain fog and makes you more alert and improves your mood.9 

Side Effects of a 24-Hour Fast

A 24-hour fast can benefit your health but isn’t great for everyone. Some people get severe side effects such as:10

  • Hunger
  • Lethargy 
  • Dizziness
  • Headaches  
  • Constipation
  • Dehydration
  • Low blood sugar
  • Low blood pressure

Staying hydrated during fasting periods may help relieve some of these symptoms. 

“Abruptly shifting to longer fasting hours can also lead to emotional and mental difficulties, which are the main reasons why some people may not stick to this eating style for long,” says Dr. Mira.

You can also consider reducing your fasting window and slowly increasing it until you’re more comfortable. This gives your body time to adjust to the change. 

Doctors don’t generally recommend fasting to people under the age of 18 or to pregnant or breastfeeding women since their bodies need sufficient calories for nourishment. 

They don’t also suggest fasting to people struggling with weight gain, eating disorders, or other medical conditions.

How to Start Intermittent Fasting

Before starting a fast, you need to find a schedule that works for you. The 24-hour fast or eat-stop-eat is just one way of doing it. There’s more to choose from.

Intermittent fasting apps make it easy to explore different fasting diets. They have built-in timers that remind you when to eat or fast.

Updated on September 13, 2023
Cristine Santander
Cristine Santander
Content Contributor
Cristine Santander is a content writer for KnowYourDNA. She has a B.S. in Psychology and enjoys writing about health and wellness.
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