The Fast 800

highly1111

Hi,

I was just wondering if anyone is currently trying the fast 800 - https://thefast800.com/ - it's advocated by Michael Mosley. The idea is you fast intermittently for at least 12 hours (only no-calorie drinks allowed) and then you consume 800 calories during the remaining 12 hours. The idea is that it kick starts ketosis and you lose a lot of weight very quickly. I read the book before starting and listened to the obesity code podcast and the science behind it is very persuasive. You do it for a MAX of 12 weeks (often people do it for less) and then switch to the 5/2 way of eating. You need to drink a lot of water (I'm drinking over 2500ml a day) and follow a med style diet - so 30% good carbs, 30% protein and 40% healthy fats. I'm on day 3 and have noticed benefits already - without the hunger - the med style approach he advocates really is just clean eating.

Anyone else tried it / heard of it?

pinkypinky

Have just read the book and am going to give it a go for a couple of weeks, then switch to the intermittent fasting version.

Did you have success with it?

neris

Have the book but not read it yet. Have done his 5:2 after rating that book and still try to do it. Can normally get the 1st day done on it easily but day 2 I find hard. Mixing it with proper food and exercise has worked.

silverharp

I didn't buy his books but listening to his interviews inspired me to go down the IF route with the 5:2 , if I remember at the time I overlapped it with 16:8 , which worked well for me.

jaykhunter

How can you get ketosis while eating 30% carbs?

brick tamland

Its just a method of eating less calories. The rest is rubbish talk

800 calories is not enough for anyone and not sustainable in any way. Just find out how many calories you burn a day and take away 10-20%. Simples

pinkypinky

Well, he has at least got some scientific properly conducted studies behind the method, albeit with some small sample sizes.

Weltsmertz

brick tamland wrote: »

Its just a method of eating less calories. The rest is rubbish talk

800 calories is not enough for anyone and not sustainable in any way. Just find out how many calories you burn a day and take away 10-20%. Simples

It's just a very low calorie diet. If you eat 800 calories a day you will lose fat. Probably a few pounds a week. Doubt it needs to be within an eating window though. And not really sustainable for long unless you use meal replacement products. They contain protein and stuff that expands in stomach to make you feel fuller.

Macy0161

pinkypinky wrote: »

Well, he has at least got some scientific properly conducted studies behind the method, albeit with some small sample sizes.

Who knew that scientific studies would show that massive calorie restriction would lead to weight loss?

Just for reference, as a mid-40's male at 70kg, my maintenance is 2340 calories, before exercise!

I struggle to see how 800 calories is sustainable for more than a couple of days, never mind a max of 12 weeks.

silverharp

Macy0161 wrote: »

Who knew that scientific studies would show that massive calorie restriction would lead to weight loss?

Just for reference, as a mid-40's male at 70kg, my maintenance is 2340 calories, before exercise!

I struggle to see how 800 calories is sustainable for more than a couple of days, never mind a max of 12 weeks.

if you are 70kg you have no reason to eat only 800 calories, if you were ~90-120KG it would be sustainable

Macy0161

silverharp wrote: »

if you are 70kg you have no reason to eat only 800 calories, if you were ~90-120KG it would be sustainable

Eh? I'm really struggling with the logic that with a higher TDEE, that a lower calorie intake would be more sustainable?

Weltsmertz

silverharp wrote: »

if you are 70kg you have no reason to eat only 800 calories, if you were ~90-120KG it would be sustainable

If you are 70kg then 800 calories a day is perfectly sustainable if you want to lose 5kg or 10kg. If you are in a calorie deficit your body will use stored fat for energy.

Macy0161

Macy0161 wrote: »

Who knew that scientific studies would show that massive calorie restriction would lead to weight loss?

Just for reference, as a mid-40's male at 70kg, my maintenance is 2340 calories, before exercise!

I struggle to see how 800 calories is sustainable for more than a couple of days, never mind a max of 12 weeks.

How is that maintenance calculated? Trial and error? I'd expect you to be easily under 2k calories maintenance, unless you're generally active with stuff that doesn't count as exercise.

brick tamland

Weltsmertz wrote: »

If you are 70kg then 800 calories a day is perfectly sustainable if you want to lose 5kg or 10kg. If you are in a calorie deficit your body will use stored fat for energy.

800 cals is not sustainable. 70kg or 120kg

pinkypinky

Wary of getting into a flame war on this but I've been trying it for a week now. It's sustainable.

Alf Veedersane

pinkypinky wrote: »

Wary of getting into a flame war on this but I've been trying it for a week now. It's sustainable.

I don't wish to get into a flame war either, or completely dismiss what you're saying but no one can say anything is sustainable for a much longer term after only a week.

I've had people tell me nonsense like Clean 9 and other faddy "eat very low calories" diets are sustainable until a couple of weeks in when they find it isn't.

Maybe you will find it sustainable for the 12 weeks. And great if it is for you. But a week is too short a window to say anything is sustainable in a longer term

pinkypinky

I'm not intending to do it for 12 weeks so I won't be able to. However, so far, it's manageable.

Alf Veedersane

As an aside, there is a place for very low calorie diets. There was a study with different groups with one on ~900 kcals a day until 15% weight loss is achieved and then switch to maintenance. Of the 4 groups, that group had the most weight loss over a 6-month study.

But it's not for everyone.

ETA: found where I'd read it: https://sigmanutrition.com/the-pros-and-cons-of-aggressive-dieting/

Macy0161

Basil3 wrote: »

How is that maintenance calculated? Trial and error? I'd expect you to be easily under 2k calories maintenance, unless you're generally active with stuff that doesn't count as exercise.

Based on the formula that is/ was in a sticky on this forum. Not based upon the completely sedentary, the next one up, as I aim for 10,000 steps (which I don't count as exercise).

I've been maintaining at that calories for 18 months since hitting it (with some expected fluctuations for holidays, Christmas etc where I have been over that target)

I used the same formula to calculate my tdee and deficit on the way down from 130kg plus, so I'm happy it works for me.

neris

Maybe just me but trying to live your life by any of the diets isn't compatible with modern life once you leave the comfort of your own home and even then with some diets you'll need a few weeks to see the weight loss effects.

silverharp

Macy0161 wrote: »

Eh? I'm really struggling with the logic that with a higher TDEE, that a lower calorie intake would be more sustainable?

i dont understand the question ? 1lb of body fat is in the order of 3000 calories , if someone had 10-30kg to lose they could fast ie eat nothing for 3 weeks no problem, or alternate day fast for months, whats unsustainable about 800 calories per day for a set period?
it wouldnt be my personal preferred method of losing weight but i dont see an issue with it

bladespin

Weltsmertz wrote: »

It's just a very low calorie diet. If you eat 800 calories a day you will lose fat. Probably a few pounds a week. Doubt it needs to be within an eating window though. And not really sustainable for long unless you use meal replacement products. They contain protein and stuff that expands in stomach to make you feel fuller.

Just to ad a caveat, it's not just fat you loose on a diet like this, especially over time.