Spencer Matthews has "completely overhauled" the way he lives his life to change his physique.
The 'Made in Chelsea' star shed 14lbs and saw his percentage of body fat drop to eight per cent from 17 in just six weeks, in a bid to appear in Men's Health magazine.
Matthews worked with fitness expert Shaun Stafford using a combination of diet and exercise, as well as Forza supplements to give him added energy and help burn excess fat, and Spencer admits it wasn't an easy transformation.
He said: "It's fair to say that I'm a bit of a yo-yo dieter. I get in shape for a bit and stick to my gym sessions for a week or two but pretty soon I let it all go with too many late nights, parties, booze and take-aways.
"Before I know it I'm looking pretty hefty again. But this time I was going to be given the opportunity to totally change my lifestyle for good - diet, fitness and the range of Forza supplements to help with the occasion lack of energy and deal with food cravings.
"Clearly it wasn't going to be easy to break the habits of a lifetime and Shaun began with a complete overhaul of my diet, a severe reduction on the late nights and the alcohol that went with them so that I could get the required sleep and recovery to allow my body to change. This was a 24-hour strategy to strip away the fat - not just the one hour in the gym."
Because Spencer was monitored so closely, he knew there was no chance to "cheat" on his new regime.
He added in a blog for MailOnline: "There were weekly body-fat tests and photographs every two weeks to keep me focused. That way I knew I would be caught out if I was cheating so I had to stay disciplined."
And the reality TV star was determined not to be outdone by his other castmates who were also working with experts from the publication.
He added: "I was also motivated by the fact that there were other guys from 'Made In Chelsea' also taking the Men's Health challenge - Oliver Proudlock, Andy Jordan, and Alex Mytton were also training with other top instructors so that element of competition motivated me to work even harder."
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