Detoxing side effects?

Hi guys,

I’ve just finished my first week of Huel and finished my first bag.

I started off with a few shakes a day, the moving to only having an evening meal, and then did my first 100% Huel day yesterday (5x 100g shakes = approx 2000 kcal) bar my Bulletproof coffee in the AM (coffee, butter, MCT oil).

The online calculators say my maintenance intake is about 2600. But my fitness tracker says I burn about 3500 kcal a day so who knows…

I’m feeling pretty crappy to be honest. Do you think this could be the body ‘detoxing’ from my normal diet?

Or less than usual calories?

I don’t think I’m getting any sugar in, part from the Huel, so maybe that is having an effect?

Has anyone else experienced this when switching to Huel?


In what way are you feeling crappy?

What do you do to burn so much calories? D:

I’ve just done a month of Huel 100%, and the first day I could eat “traditional” food I had a steak and chips, and a beer, my stomach was not happy at all, the microbiome is a strange beast. Yes it does take some adjusting as different microorganisms in the microbiome live off different foods, so as you switch some die and some other increase which causes the changes.

They can even influence your mood -

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Yeah, I honestly don’t think “detoxing” is a real thing.

Here is some info on how Fitbit comes to that number:

I try to walk at least 10,000 steps a day - my average is about 13,000 - and go to the gym 2-3 times a week.

I’m 6ft1 and about 90kg.

The effects have mainly been brain fog, lack of focus, low energy, irritability, slight nausea, headaches.

I think it probably is down to lack of calories.

Yesterday I had 6 x 100g (410 kca) of Huel so 600g which is about 2,460 kcal. Prior to that I only had about 2000.

I felt a bit better than so will stick to that level and try and get in a big Huel meal around lunch time to prevent myself from falling behind.

Today I had a Bulletproof Coffee for breakfast, then my first Huel at 1245pm which was 150g, so approx 600 kcal.

Will have another same sized one at about 4pm and then 6pm, then hit the gym and have one PWO.

I’ve been able to tighten my belt by an extra notch - down to the smallest setting - so something is happening in that department.

Have you read the Brain Maker book? Its crazy if true:

Did you follow the steps here:

According to the calculator you need approx 3000 calories per day (based on 25 years old, not sure of your age) to maintain your weight. So 2000 cals is way under, if you want to lose fat we recommend a 500 cal per day deficit.

Thanks. I’m 35 and with light exercise 1-3 times a week it says 2595 is maintenance.

With exercise 3-5 times a week its close to 3000.

I’m probably somewhere in between.

I’ve had 2x 150 g of Huel today and feel ok so far. Bit bunged up but hopefully that will pass!

So how has it been since?

Yeah fine. No problems, thanks.

Either I was just having withdrawals from not eating chocolate/sugars or I was under-feeding myself.

Now I have about 2,500 to 3,000 calories a day and feel fine.

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That’s probably the most likely explanation. It could also have been unrelated. You might have just been a bit ill.