800 Calorie Day

800 Calorie Day

The 800-calorie-per-day diet, known as the Fast 800, is one of the most popular low-calorie diets out there. Created by Dr. Michael Mosley, the Fast 800 is helping people all over the world lose body fat faster than they thought possible. This article provides an overview of the 800-calorie-per-day diet to discover if it’s worth taking on.

Fast 800 Diet Basics?

Calorie Blog

With Dr. Mosley’s most recent regimen, calorie counting takes center stage during the rapid weight reduction phase. He asserts that the “magic amount” for effective weight loss is 800 calories.

“The latest scientific data illustrate the health and weight benefits of intermittent fasting paired with a nutritional plan that promotes quick weight loss,” he stated in the Daily Mail.

Followers of the Fast 800 program are urged to limit their daily caloric intake to 800 for at least two weeks, although they are free to continue. The idea behind the diet is to customize it to meet your individual needs. You can either stick to the simpler 5:2 plan or, the more rigorous 800-calorie plan for up to 12 weeks.

The first two weeks of the Fast 800 diet require you to consume only 800 calories daily. After that, you transition to 5:2, during which time you consume 800 calories per day for two days and eat at your maintenance level for the rest of the week. 

After two weeks of eating 800 calories per day, you should lose a sizeable amount of weight. You then switch to eating 800 calories twice a week and stick to a Mediterranean diet on the other days while practicing portion management.

Dr. Mosley recommends that followers of the 800-calorie diet focus on eating natural, unprocessed while cutting out carbohydrate and sugar-laden foods such as white bread, savories, and pies. Instead eat plenty of fruits and vegetables, such as green beans, fatty fish, and healthy fats from oils such as coconut and macadamia. He also recommends using such spices as black pepper, a pinch of salt

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Dr. Mosley also recommends consuming 45-60 grams of protein per day, sourced from such lean sources as eggs, tuna salad, and chicken. 

According to Dr. Michael Mosley, who is widely recognized as the godfather of intermittent fasting, the Mediterranean diet is the ideal form of eating, providing a good mix of protein, fats, and starchy carbs. 

Who is the 800 Calorie Diet For?

If you’re looking for a quick, effective way to lose weight, the Fast 800 Keto is a good option. It is designed as a short-term, rapid weight loss phase for people with a lot of weight to lose.

The average weight loss on the 800-calorie diet is 3-5 pounds per week. 

Once you reach your initial weight loss goal, you should switch to a more sustainable form of intermittent fastings, such as the 16:8 diet.

The 800 Calorie Diet In Practise

fruits and vegetables with calorie

The body’s two energy sources are glucose and fat. Glucose, the preferred form, comes from the foods and beverages that you consume. This is what your body draws upon to meet its energy needs. The leftover calories go directly to your fat stores. 

Intermittent fasting stops the supply of glucose to your muscle cells. After approximately 12 hours of fasting, your body’s glucose levels will be depleted. At this point, it has no choice but to turn to its stored fat reverses to meet its energy needs. As a result, you will literally be burning fat with every breath you take. 

When you follow an intermittent fasting approach to weight loss, including reduced calorie diets, you will eliminate those between-meal snacks that cause blood sugar levels to go crazy. It also reduces the likelihood of experiencing insulin resistance, which can lead to weight gain and can be a contributor to heart disease. 

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Following the 800-calorie diet will also reduce a person’s risk of Type 2 Diabetes. 

Shakes are Included


The Fast 800 is the first time, according to Mosley, that he has chosen to add meal replacement shakes. These are not the traditional shakes that people used to purchase from the pharmacy but rather prepared beverages that are loaded with healthy nutrients.

With each smoothie containing 200 calories, you can simply and quickly refuel on nutritious plant-based fats, vitamins, and other critical nutrients while on the go. The Fast 800 diet does not require them, but according to Dr. Mosley, they are excellent for “keeping you feeling full and encouraging fat burning.” He adds that you shouldn’t just rely on smoothies for calories and shouldn’t consume them for an extended period of time.

Does It Work?

Dr. Mosley decided to test the diet on himself while developing it. He took several months to put on more than 6kg while he was creating the program. He acknowledges that the first two weeks of the diet sometimes left him feeling “down on energy,” but the 5:2 phase that followed was “quite simple.”

In just two weeks, he lost over 5 kg. Similar results to these have been reported by thousands of people all over the world. 

800 Calorie Diet Precautions?

doctor measuring blood pressure to a smiling woman

The 800 Calorie Diet involves reducing your calories below a level that is generally considered to be ideal by medical professionals. 

Before beginning the diet, people should speak with their doctor or dietician.

Give your body some time to become used to an 800-calorie diet. 
Fatigue and diarrhea are two symptoms of sudden calorie reduction. This can lead to dehydration. So, make sure that you increase your water intake when you start on this diet.
Pregnant women and mothers who are breastfeeding should not follow the 800 Diet. 

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The Fast 800 is a rapid weight loss plan developed by Dr. Michael Mosley to lose belly fat and improve overall health. It involves two weeks of reducing calorie intake to 800 calories per day for two weeks and then switching to a 5:2 diet, where you do two days at 800 calories and follow a normal Mediterranean diet for the other five days. Michael Mosley’s latest plan is an effective weight loss method that can help obese people lose weight quickly. However, it is quite a restrictive diet and should only be done for a short period of time. 

Frequently Asked Questions

Is the 800-calorie diet safe?

The 800-calorie should be safe so long as it is done for a short period of time. Eating less than a thousand calories per day long term will result in loss of muscle mass, so you should not follow this diet for more than 12 weeks. 

How much weight can I lose on the fast 800 diets?

In one study, a group of people who followed the Fast 800 diet for 12 weeks lost an average of 10.5 kg. That gives a good indication of how much weight you can lose on this diet. 

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Steve Theunissen

Steve Theunissen is a former gym owner and personal trainer based in Tauranga, New Zealand. He is the author of six hardcopy books and more than a hundred ebooks on the topics of bodybuilding, fitness, and fat loss.

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