The Liverpudlian singer believes that he "has never had so much energy", due to his new carbohydrate-free diet which was recommended to him by Barlow's nutritionist.
Colton told Closer: "I'm having meals of 60% cooked veg, 20% meat and 20% raw veg. I've never had so much energy!
"He comes over to the house and takes me on jogs round the garden! It's weird not doing a double-take at him anymore."
The 22-year-old added: "Sometimes, my phone buzzes and I see the name 'Gary Barlow' and I'm like, 'The one from Take That, right?'"
Take That singer Barlow recently opened up about his previous weight issues.
> Craig Colton drops a stone in weight in one week