Pippa Middleton's pre-wedding diet is one you've most likely never heard of before.
According to E!, the 33 year old is a fan of the Sirtfood diet, which concentrates on 20 foods that help to speed up your metabolism and burn fat.
These foods include strawberries, kale, arugula, red wine, cocoa, walnuts, strawberries and coffee. They are high in polyphenols, which supposedly help activate a person's "skinny genes."
But don't be fooled, it gets a little wild.
RELATED: Pippa Middleton and her fiancé, James Matthews
The diet is broken down into two phases. Week one requires you to only consume 1,000 calories a day for the first three days, through three Sirtfood juices and one meal a day. Then, you consume 1,500 calories a day with two juices and two meals for the rest of week one.
Next follows a "maintenance" phase where you can eat three SirtFood meals and one juice a day.
Dietitian Brigitte Zeitlin told The Cut that the diet is actually quite dangerous, saying, "It's unhealthy and unsafe to eat below 1,200 calories a day."
She added that after a person gets off of the diet, they are probably going to gain the weight back again.
RELATED: Pippa's style transformation
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