3. Experimental protocol and methods. A single-centre, randomized, cross-over design study consisting of a screening visit and four test days, which will be approximately 1 week apart The subjects (18 healthy volunteers for main study plus 4 for pilot studies) will receive (according to a randomization schedule) each test day one out of four test products: 1) glucose (control) 2) fructose, 3) glucose with fructose and 4) fructans. On each test day, volunteers will have a baseline scan in a 1.5T scanner, consume one of the products instead of breakfast at 09:00 and will be imaged in the scanner at intervals for 5 hours using a range of MRI sequences.