The 36-year-old mother-of-three has wowed fans with her increasingly slim frame.
Fans have both complimented and criticised Holly for her changing look on her social media accounts, and the star is understandably keen to keep quiet about her weight loss methods.
She does this because she is anxious about encouraging mental health problems for women to do with their weight.
She said: “I don’t want to encourage eating disorders. I try not to focus too much on my appearance. As long as I’m being healthy, that’s good enough for me.
“I’m quite active and I try not to let the way I look be the main focus because it’s not the important thing.
“I actually avoid talking about my diet and exercise regime because I have interviewed so many people affected by eating disorders.”
However, some information about how Holly manages to stay healthy and glowing has found its way to the public.
The TV presenter told fellow morning show host Lorraine: “I think you sort of get – the children are a little bit older, so I’ve got a little bit more time for myself.
“And I’m always one of those people that if you feel happy and healthy that’s all that matters.”
However, Holly’s former fitness instructor revealed after the presenter had her children she helped her spring back tiny shape.
Holly used pilates once a week, post-baby.
Her former pilates instructor Lynne Robinson told the Sun: “I worked with Holly for several months, teaching her privately at her home once a week.”
“Holly had postnatal matt work classes which concentrated on strengthening and toning her core.”
“The exercises would have also helped strengthen the pelvic floor which can loosen after pregnancy, as well as help trim the waist and flatten the stomach.”
It was recently revealed that Holly uses powdered milk to stay youthful.
Holly Willoughby weight loss: Star stuns with shrinking frame – how does she do it? | Diets | Life & Style