Hi all,

I’ve started the fast800 this week. My goal is to lose 5-8kg depending on how I feel at my lower weight.
I’ve struggled to lose this weight just by cutting cals and exercising unless my deficit is quite drastic, which leaves me lethargic.
Have also done atkins and low carb (<50g) previously, but found I was unable to shake the lethargy even after 3 weeks despite getting plenty of fluid and salt and monitoring macros, and increasing calories overall at times – still didn’t help.
I get enough sleep and don’t exercise strenuously – it’s really the dietary changes that seem to cause the fatigue.

So I’m curious to know about others’ experiences on the fast800 when it comes to lethargy and effectiveness – especially if like me you don’t have heaps of weight to lose.

Thanks in advance!

Hey! Love your username 😉
I’ve got several questions for you : what’s your body fat percentage? Waist measurement? BMI? I guess my overall question is do you have enough fat in storage to sustain you once in ketosis?
Also what were you macros like in previous instances when you tried this new diet? You’d want to try and keep carbs below 20g, moderate proteins ie ~0.8g per kilo of targeted weight and the rest in fat.
Usually you should get in ketosis fairly quickly, prob 2 weeks and then get that boost of energy.
I have a total of 15kg to lose, I’m already half way after 5 weeks but I def hav enough fat store to keep me going for a while! 😁

I started Fast 800 two and a half weeks ago. I had 7.5 kgs to lose. I’m very short so possibly should have adjusted it to Fast 700, but figured I didn’t mind if it was a little slower. I am doing it with my hubby. My starting BMI was borderline healthy/overweight and since turning 40 I have struggled to get back to my previous “normal” weight.

I think it’s crucial to make sure you do the recommended physical activity and for motivation take measurements with tape as well as scales.

Week 1 I lost nearly 2 kgs. Then nothing for a week, but my measurements changed. I lost another inch around my waist. I looked better.

I researched fluid retention and started taking a daily magnesium/b6 supplement as well as 2 prunes to encourage BMs, and the effect was noticeable after 2 days. I lost another kilo and a half, so all up I’ve lost 3.5 kgs in 2 weeks off a short frame (5 foot).

The first 3-4 days of the diet were tough but I have felt very well since. I feel great. I’m sleeping well and going to bed earlier. I’ve found chewing gum helps a lot between meals.

Good questions Louise, thanks for taking the time!
I’ve used calipers to estimate my bodyfat at about 30%. My waist measurement is 75cm and BMI is about 23. I’m a bit of a skinny fat person – normal weight, but very squishy!

Macros previously have been carbs below 20g, and probably too high in protein without adequate fat – I think I went about 40% for each but it was a while ago now.

7.5kg after 5 weeks is great!! Congrats, it must be very encouraging to see the changes!

Theory is that the fat is the satiating part of the macro equation. Maybe up your fat and make sure you don’t over do on proteins as they act like carbs when you go over your goal/limit.
How are you feeling now? You have been at it for a couple of days? I would expect keto flu p hit soon but it might not, some ppl don’t experience it at all 🙂

Hi ilovepasta
I started Fast 800 nearly 3 weeks ago. I found the first 3-4 days challenging, and I was waking up in the middle of the night thirsty and needing to pee. However I have not felt as well as I have felt since starting for years.
I started at the upper end of my healthy range, and am aiming to get down to the lower end.
Because I’m short, I think I should lower my calorie intake a bit further than 800, but I’m happy with the rate that I’m losing. So far 3.85 kgs, 3 inches off my waist. I’m really happy with that. I had a plateau last week that I knew in my head had to be fluid retention and constipation. Somewhere on the forum 2 prunes a day was recommended and that has been perfect. Also I started a daily magnesium/B6 supplement, and 2 days after that the scales were much less discouraging!