BBC Scotland, Edinburgh and East reporterHe trained hard and followed the high protein, low carbohydrate diet favoured by many bodybuilders wanting to gain muscle.
"At first when I started eating a lot more food and carbs I felt in a lot of pain because my body wasn't used to it as I had been dieting on very little food for so long," he said."But suddenly on this high carb diet I had all this energy so I could train for longer and harder and I felt stronger.Image caption,A health and nutrition expert from the University of Edinburgh, Prof Lindsay Jaacks, said carbohydrates were of "critical" importance for exercise.
In addition to taking the Mr Universe title, he has dominated Masters competitions since changing his diet, winning Mr England, Mr United Kingdom, Mr Britain, and Mr World titles.Mark, who runs Taylormade Gym and Fitness in Leven with his wife Anita and sons Bodhi and Dalton, said he started bodybuilding after working for a famous Scottish soft drinks firm.
"Carbohydrates are absolutely critical because that's what the brain and the muscles use for energy sources during exercise.