The 33-year-old pop star has revealed she only has water and other drinks for almost two days at a time on the basis that it reduces inflammation – but Ellie insists her approach has been given the green light by doctors.
She told the Sunday Mirror newspaper: “I do it very safely by having a purposefully nutritious food day the day before and after.
“On the fast day, I drink high-grade electrolytes and a lot of water (plus tea and coffee). Fasting is safe and beneficial unless you are diabetic or have serious health issues.
“I built my way up to 40-hour fasts over time (started with 12). Fasting from time to time is a great way to give your digestive system a break.
“It helps blood sugar control, and helps fight inflammation – the mother of all health problems.”
Meanwhile, Ellie recently confessed to being a “jealous, chaotic, frenzied person” ten years ago.
The chart-topping star began her career in 2009, shortly after graduating from the University of Kent, but the quick turnaround meant she didn’t have a chance to understand her emotions throughout her youth.
She said: “I wrote a song about jealousy the other night because I was a jealous, chaotic, frenzied person in my 20s.
“I didn’t know who I was. I went straight from university to being on tour, so I had no chance to settle into a routine and understand my habits and my personality.”
Ellie entered into “crazy” relationships to help her feel secure, despite being secretly miserable inside.
The singer – who married art dealer Caspar Jopling in 2019 – said: “If you enter into a relationship as that person, then you will attract the same person that isn’t right for you.
“Then for whatever reason, you keep going with this relationship because you feel safe in it and you feel like I’d rather be in this crazy relationship than be single.”