What is it?
The rapid weight loss stage of the diet involves eating 800 calories a day. If you decide this approach is for you, we recommend that you stay on this stage for a minimum of 2 weeks, though you can stay on the plan for up to 12 weeks depending on your goals and how much weight you have to lose.
To most people 800 calories doesn’t sound like a lot, and that is why we have based the 800 calorie a day meal plans in the online programme on delicious Mediterranean style diet recipes, which are designed to keep you feeling full and satiated.
Who is it for?
The Very Fast 800 involves rapid weight loss. It is also a highly effective way to bring down raised blood sugars (i.e. pre-diabetic or type 2 diabetic). Over the past few years major studies have shown that following an 800 calorie a day diet is much more effective than going “slow and steady”, with typical weight loss of around 10kg. Rapid weight loss is also the best proven way to reverse type 2 diabetes and prevent people with pre-diabetes from becoming diabetic.
Because The Very Fast 800 is an intensive approach to weight loss, it is not suited to everybody. As with any diet, you should speak to your usual health professional before commencing The Very Fast 800 approach, and please see our medical disclaimer for information regarding cautions and exclusions as to who shouldn’t do the diet. If you find that this approach isn’t for you, you can skip straight ahead to The New 5:2 plan or the Way of Life.
How it works
1. Burning fat by flipping the metabolic switch
Your body is like a hybrid car; it runs on two different fuels – sugar and fat. When your body needs a quick burst of energy, the first fuel source it turns to is the glucose (sugar) in your blood. Next it will draw on the sugar stored in your liver and muscle (glycogen). Only when this starts to run low does the body turn to its fat stores. Your body can’t just burn fat. Instead it turns some of your fat stores into ketone bodies, which its uses as energy. The buildup of ketones in your blood is called “ketosis”.
When you are on a low calorie diet (800 calories a day) you will begin to rapidly use up your fat stores. The first fat to go will be that around your gut, the visceral fat. This is also the most unhealthy fat. Because The Very Fast 800 plan is also moderately low in carbohydrates, this will add to the fat burning.
People worry about running out of energy on a low calorie diet, but the reality is that most of us have such big fat stores we could go for months without eating. The reason you may feel hungry and perhaps more tired than usual for the first week that you are on the diet is because your body is having to adapt to running on a different fuel, fat. But you should soon start to feel better – more energetic and clearer thinking.
2. Improve your insulin resistance: stop snacking and watch the hunger disappear
We are often told that we should snack between meals to avoid getting hungry. There are two serious problems with this advice. Firstly, the more often people eat, the more they eat overall. And secondly, if you are snacking all the time that means you constantly have lots of sugar circulating in your blood. Constantly topping up your blood sugars is a really bad idea.
The reason you don’t want to keep you blood sugars topped up is that having high levels of sugar in your blood damages your arteries and nerves. Sugar, in high concentrations, is toxic to the cells. So, after a sugary, carby meal your pancreas produces lots of insulin to bring your blood sugar levels down. Unless you go for a run, to use that sugar up, most of those excess calories will get stored as fat.
And it gets worse. Because if you have lots of snacks and sugary treats then your pancreas needs to produce more and more insulin to bring those blood sugars down. It is like shouting at the kids. After a while they stop listening. The same is true of your body; over time you become insulin resistant. When the pancreas can no-longer produce enough insulin to keep your blood sugars in check then you will be on the downward journey to pre-diabetes and eventually diabetes (where the pancreas just packs up).
The good news is that an 800 calorie diet is a highly effective way to lose weight and reduce insulin resistance.
How to do it
The Very Fast 800 plan uses Mediterranean-style ingredients to keep you feeling fuller for longer. We also recommend that you take a multivitamin whilst following this plan to guarantee you are getting all the necessary nutrients and vitamins. If you join our online programme we provide you with delicious meal plans so you don’t have to worry about counting calories.
You may also want to use shakes for those busy days when cooking just becomes too difficult. We have developed The Fast 800 shakes to reflect the quality of our nutritionist-designed meal plans. Low in sugar and based on all natural ingredients, they are designed to fit perfectly alongside the rest of The Fast 800 plan, They deliver an exact balance of vitamins, minerals, protein, fibre and probiotics.
It is also extremely important to stay hydrated when following this plan. As a guide, try to take in at least 8 cups a day, or about 2 litres. The commonest side effects of going on a rapid weight loss diet are headaches and constipation, both of which can be prevented by drinking lots of water. One other possible complication of rapid weight loss is gallstones, though gallstones are also very common in people who have diabetes or are overweight.
The evidence
The DiRECT trial (2018) (1)
The DiRECT trial is a ground breaking study carried out in the UK involving nearly 300 overweight type 2 diabetics. The participants were randomly allocated to either a 800 calorie diet for 12 weeks, or to a standard diet. The participants on the 800 calorie diet made a gradual return to a more normal diet after the 12 weeks of 800 calories. Both groups were then followed for two years.
The results in the rapid weight loss group were astounding. Average weight loss was 10.5kg and nearly ¼ lost over 15kg. Even better, nearly half of them got their blood sugars back to normal despite not being on medication. Two years on and those in the rapid weight loss group are still going strong.
The DROPLET trial (2018) (2)
This was an 800 calorie trial, carried out by researchers from Oxford University with overweight patients and followed for a year. Average weight loss at the end of a year was again 10kg, with the 800 calorie group showing big improvements in blood pressure, cholesterol and improvements in biomarkers of cardiovascular and metabolic risk compared to the control group.
Following the success of DiRECT and DROPLET, the NHS is proposing to allow GPs to consider prescribing a very low calorie diet to patients with a high BMI.
The PREVIEW study (3)
The PREVIEW lifestyle intervention study is, to date, the largest, multinational study aimed at preventing type 2 diabetes. 2,326 pre-diabetic patients from eight countries followed an 800 calorie diet for eight weeks as part of a longer term weight loss management and diabetes prevention study.
After eight weeks, participants had lost an average of 11kg, and experienced an average reduction of 10cm in waist size.