Impact of Macronutrient Composition of Energy-restricted Diet and Exercise on Body Composition and Appetite Hormones.

This will be a block randomised parallel study, with one group of participants undergoing exercise training combined with the consumption of a calorie-restricted high CHO-low FAT diet and another group undergoing exercise training with consumption of a calorie-restricted low CHO-high FAT diet. The interventions will last for 4 weeks. Prior to and after the interventions participants will undergo a 5-hour experimental trial, which will involve body composition measurements by the D2O method, appetite hormones, insulin via blood collection and subjective appetite via a visual analogue scale. During the experimental trials, participants will consume breakfast and ad libitum buffet-style lunch. Prior to the first experimental trial, participants will be subjected to a screening process followed by a preliminary exercise test in the metabolic research unit at New Lister Building (NLB), Glasgow Royal infirmary (GRI). Participants will also be asked to record their food and drink consumed for 4 days (3 weekdays and 1 weekend) prior to and during the four last days of the intervention. By following this step, individual diets will be designed based on participants preferences with restricted energy intake and different macronutrient compositions. Dietary intake records will allow a comparison of participants' calorie intake before and after the intervention. During intervention participants will consume either energy-restricted low CHO-high FAT or energy-restricted high CHO-Low FAT diet and exercise (brisk walking) while wearing a heart rate monitor 3 times a week after 5 minutes of warm-up, and 5 minutes The duration of the brisk walking will increase after week one from 30 to 45 minutes and to 60 minutes at week three and four. Participants will be advised to cool down after the brisk walking session. During the intervention, participants will be encouraged to avoid alcohol consumption. In case this was not possible, a maximum amount of two units will be allowed per week.