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The Fast Diet

Fast Diet Review (UPDATED 2024): Don't Buy Before You Read This!

Lose Weight, Stay Healthy, and Live Longer with the Simple Secret of Intermittent Fasting

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What is it?

The Fast Diet is an overall health and weight loss diet that emphasizes fasting during certain days of the week. It’s also known as the 5:2 diet, and it’s claimed to help burn fat by limiting calories and improving how the body reacts to food.

One has to follow a strict habit of not eating on certain days, and there’s a different calorie limit for men and women. It’s essentially a form of intermittent fasting, but it’s specialized and added as a part of a full diet.  The official book also adds the principle of that which does not kill us, makes us stronger. In reviewing many kinds of weight loss diets our review experts found the 18Shake Diet to be the best. It’s made up of an appetite suppressing meal replacement and a fat burning diet pill. Customers have given it rave reviews for its weight loss effects. Learn more about the 18Shake Diet by visiting the link here.

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Fast Diet Possible Side Effects

The Fast Diet emphasizes different eating habits and limits for both men and women:

Men: Only 600 calories are allowed on the 2 fasting days.

• Women: 500 calories are allowed during the 2 fasting days.

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It’s also referred to as the 5:2 diet due to the 5 days you’re allowed to eat normal, and 2 days where you cut around 25% of your calorie intake. It’s highly recommended to eat only lean protein rich foods for the fasting days, as getting 600 to 500 calories is easy to do if one is not careful.

For suggestions on food it’s advised to eat:

• Legumes, skinless chicken, nuts, carrots, strawberries, other low calorie vegetables and low glycemic foods.

In order to avoid feelings of hunger it’s advised to eat later in the day during fasting. This is to have something in the stomach to provide nourishment for when you really need it.

It’s also recommended to try and eat around 50 grams of healthy protein during fasting. You can resume eating normally on your non fasting days, and there’s no adherence to any amount of calories.

While not eating is a way to help with weight loss, the issue is that this can be extremely hard for some. This is also not considered safe for everyone, and it would be highly advised to seek the advice of a medical professional.

Web MD has also found:

“many health experts don’t recommend fasting”

They also found:

“it may slow your metabolism, making it even harder to lose weight”

A major issue with fasting like this is that it may cause binge eating to occur. This desire happens because once you have access to food; it makes it harder to control your hunger as the body wants to make up for the loss of calories. Eating such a reduced amount of calories can also potentially cause side effects such as:

       • Headaches, low blood sugar, and fatigue.

       • Mood swings, irritability, and loss of energy.

• Lack of mental focus, difficulty concentrating, and extreme hunger.

It can also take a lot of willpower which can make it difficult for most to begin. Click on the link provided for a list of the top ranked weight loss diets.

EDITOR’S TIP: Combine this diet with a proven meal replacement such as 18 Shake for better results.

Fast Diet Overall Quality

Whether or not one can sustain such an extreme reduction in calories varies from person to person. Some might find it difficult to start, especially those who have no experience with fasting.

Certain are advised not to follow this diet as it may cause serious side effects.

There’s also some evidence that shows metabolism is slowed down, making it harder to lose weight if one were to reduce calories this low.

Another major issue is due to the lack of guidance during non-fasting days. You’re allowed to eat any amount of calories that you’d like. This makes it possible that one might binge eat to make up for the loss of calories during fasting. Follow the link cited for the list of the best weight loss diets.

The Price and Quality of Fast Diet

The official book currently retails for $10.87 on Amazon.com. The only other prices are related to the kinds of foods one chooses on their non-fasting days.

Fasting can be an approach to weight loss, but it’s extremely difficult and does not guarantee weight loss. Some actually gain weight as they suddenly feel the urge to overeat while not fasting.

Some people are also unable to start this diet due to health concerns. It can be difficult to function normally or to put forth effort in basic tasks. Overall this is another version of intermittent fasting which may not work for everyone. For the list of the top ranked weight loss diets, follow the link here.

Business of Fast Diet

The book was created by a Michael Mosley and Mimi Spencer. Michael Mosley has a background in psychiatry and Mimi Spencer is a journalist.

An official website is offered which provides a BMI calculator and more information on the Fast Diet. An online forum is also provided for likeminded dieters to ask questions and provide a community of support.

They also provide up to date information about the topic of fasting. Different books are also provided each one with their own emphasis on tips or cookbooks. 

EDITOR’S TIP: The top 10 list of the best diets is available here.

Customer Opinions of Fast Diet

Provided below are some select reviews from users found online:

“After several weeks of trying and cutting back on fast days I have not lost any weight”

“Discussion on the topic of fasting is quite shallow. It’s written less by a doctor but more of a reporter”

“don’t like that hungry feeling and going without eating”

“This would be an unhealthy and unnatural way to live. I can’t see myself following this diet”

Some found it impossible to keep using the diet as it was too restrictive. People have struggled to make sure they were underneath the allowed calories, only to suffer and only able to think about food.

There were also issues from people who made sure to follow the diet but who failed to notice any weight loss. People who had to measure out their foods were concerned about the little amounts of food allowed.

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Conclusion - Does Fast Diet Work?

The Fast Diet is made to be a comprehensive diet for overall health and weight loss. While reducing calories is the traditional way to lose weight, some found the caloric restriction incredibly difficult. Some experienced side effects and man found it difficult to follow. There’s also been research which shows that metabolism slows down during such a limited caloric intake. The book was also not written by health professionals.

In reviewing countless diets our review experts found that 18Shake Diet is the best. Customers have given it rave reviews for its potent weight loss effects. It’s made up of a fat burning diet pill and an appetite suppressing meal replacement shake.

Only natural ingredient are added free of colors, stimulants, preservatives, artificial additives, or binders. Discover more about the 18Shake Diet by clicking this link.

How Does The Fast Diet Compare?
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User Feedback

(Page 1 of 1, 6 total comments)

Roy Christopher


I really like the fast diet. I've been on it seven weeks and have lost almost 8 lbs and 2 inches off my waist. I enjoy the fast days because I don't have to think about food. Odd huh?
I'm a snacker and it's nice to know "today I don't snack"
I will stay on this program indefinitely. It works for me.

posted Apr 30th, 2016 5:34 am



I saw the documentary a couple years ago. Dementia runs in the family as well as other issues. I also have not had success on other weight loss plans. Have started the fasting and also FastExercise. Second week and finding it easy. I use a little Garcinia Cambogia for appetite suppression. Feeling good : )

posted Feb 11th, 2015 12:03 am

Marie Nemetz


I have been following the Fast Diet for 9 months and have lost 20 lbs, I have been able to maintain the wgt. Loss and Iam extremely happy with the results. This food plan has been the easiest program I ever participated in.
My lab results are also improved .

posted Apr 22nd, 2014 6:09 pm


I have been on this diet for 12 weeks and have lost 14.6 lbs. I have never felt better. I sometimes do 3 days of 500 calories, as it is very easy and I don't feel hungry.

posted Oct 1st, 2013 5:48 pm



I have been on this diet for 12 weeks and have lost 14.6 lbs. I have never felt better. I sometimes do 3 days of 500 calories, as it is very easy and I don't feel hungry.

posted Oct 1st, 2013 5:46 pm



I have been on this for 4 weeks and have lost 10 lbs. It is surprisingly easy. I am also trying to limit my non-fast day intake to

posted Sep 15th, 2013 2:31 pm


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BACKGROUNDBACKGROUND Start the Diet Now Advertisement

The Fast Diet, written by Dr. Michael Mosley and Mimi Spencer, promotes intermittent fasting as a means for weight loss, optimum health and longevity. In the book, the authors write, "Intermittent fasting can put us back in touch with our human selves. It is a route not only to weight loss, but also to long-term health and well-being."

The book is based on two things: Modern scientific research and the authors' own personal experiences with fasting, especially Dr. Mosley who lost 20 pounds, a high percentage of body fat, and lowered his fasting glucose levels to normal through an intermittent fasting diet.

Mimi Spencer offers practical advice on how to follow an intermittent fasting diet safely and effectively with meal plan options, as well as a female voice of experience in fasting.

The diet is based on a model called the 5:2 diet approach - 5 days of eating normally without any restriction, and 2 days of loose fasting, meaning dieters can have 25% of their normal day's calorie intake - roughly 500 for women, and 700 for men. Those calories should come from lean proteins and vegetables.

The Fast Diet approach claims to yield weight loss, an abundance of health benefits and ultimately, longevity. This is because going without food has been one of the only interventive dietary methods that can prolong life, at least in animals. Similar research is now being done on humans.

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  • No complicated rules to follow
  • An easy-to-follow strategy
  • Based on scientific research
  • Dieters don't "starve" on any given day
  • Still enjoy the foods you love most of the time
  • Claims to cut longterm risks of diabetes, heart disease, cancer and other serious diseases
  • Includes detailed meal plans
  • Other benefits include a sharpened mind and longterm weight management
  • Not necessarily a "proven" method
  • May not be safe for everyone

The Fast Diet promotes the 5:2 diet approach, meaning dieters eat normally 5 days of the week and restrict their caloric intake to 25% of their daily needs on 2 "fasting days" of his or her choice.

This approach is thought to reconnect our bodies with our "human" nature while also promoting weight loss, optimum health and longevity.

The book includes a month worth of meals in photos, as well as an extensive list of meal plans demonstrating how to follow an intermittent fasting diet safely and effectively.




Based on Dr. Mosley's extensive research and own personal success with intermittent fasting, it seems like a safe enough approach to losing weight.

Although at first glance it may appear the authors are promoting starving to lose weight, they're actually promoting a diet method that keeps our body guessing to promote weight loss.

Also, because dieters restrict their calorie intake to 25% on their fasting days (never going completely without food), this has a tendency to shrink overall appetite, prohibiting dieters from overeating on their 5 normal eating days.This is one more way the diet promotes overall calorie restriction and weight loss.

Though this diet approach may not be safe for everyone, it seems to be a safe enough method for losing weight and living longer. There doesn't seem to be anything fundamentally wrong with The Fast Diet, though more research is still being done to confirm the safety and effectiveness of Dr. Mosley's methods.

Common MisspellingsCommon Misspellings

the fast diet, the fasting diet, the F.A.S.T diet, dr. michael mosely, micheal mosley

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