Known for her Location Location Location hosting spot, Kirstie's hourglass figure and desirable curves are the envy of women everywhere.
Now, the TV star has revealed that since hitting her 40s she's felt some extra pressure, after gaining a bit of weight as she'd gotten older. Speaking on Chris Evans' Radio 2 show she said, 'I put on 2 stone between 40 to 44/45.
'I blame this totally on my work because being on the road, on location, is very unhealthy. The crew eat like gannets [and] there's always food everywhere; there are crisps, bacon sarnies and Haribos. It's cold, so you eat because it's cold, and you eat late at night.
'You're in pubs and hotels, and it's just not healthy.'
Recently the star has been showing off a newly slimmed-down figure after losing two stone, dropping from a size 16 to a 12.
The 45 year old credits her success to nutritionist and author of Eat Nourish Glow Amelia Freer. Amelia, who was formerly assistant to Prince Charles before training as a nutritionist, has transformed the diets of stars such as Sam Smith and James Corden.
Kirstie has opened up about the secrets to her weight loss success, including speaking to a psychotherapist and having an extensive medical examination, as well as praising the work of Amelia Freer.
Fans and followers noticed Kirstie's slim figure while she was busy working up a sweat hitting the pavements. Posting her running progress on Twitter, Kirstie admitted that although she was tired she was still willing to get moving and go on a run.
Replying to her tweet which reads, 'Sleepy but off for a run in my new favourite T-shirt' followers instantly noticed her slimmer-looking face.
Fans tweeted encouraging messages such as, 'have you lost weight? Looking very healthy either way Ms Allsopp' and 'Wow you've lost pounds! Looking healthy there Kirstie. Well done', so it seems her good work hasn't been going unnoticed!
Cut out sugar
Following Amelia's advice which saw Sam Smith lose over a stone in two weeks, Kirstie has discovered that completely cutting out sugar is key to her success.
She admits it's a difficult task and has been quoted saying, 'But I do find I have to work really hard to keep it from creeping up, because when I'm filming around the country I've got little control over what I'm eating. If I stay away from sugar, the weight stays off like it did when I was in my 30s, a size 14 on the bottom and 12 on the top.'
Another huge part of following the famous Amelia Freer detox is to cut out alcohol from your diet when trying to lose weight. Kirstie is said to have stopped all alcohol consumption which has played a huge part in her stunning two stone weight loss.
Writing for the Daily Mail, Amelia has said of alcohol in your diet, 'Just a few glasses of wine contains more sugar than a chocolate bar.
'Alcohol can also lead to huge blood sugar fluctuations, which directly impact your energy levels, food choices and waistline.'