Been on this vegan diet for nearly a week now. Have been letting my body adjust to this very demanding diet before I thought I would engage in any physically demanding activities. I use to compete as a distance runner and a sprinter nearly 3 years ago now. I've basically lost all my core fitness and am intending to regain it. I weighed 78kg and stood at 6"1. Nowadays I weigh about 92kg. I'll probably start of this training program by reintroducing myself to distance running. All runs will be ran at an easy pace for approximately 30 minutes. Will not be considering speed work or hill repetitions within the first couple of weeks. Once I've got that foundation, will engage in speed and hill work. Fartlek is a good alternative for someone who can't train on a track. It means speed play, where you alter the speed throughout the run. Circuit training will then be introduced with such workouts like press ups, sit ups, squats, burpee's, squat thrusts, planks etc. Will also use an aerobic step and a speed rope to help improve agility as well as strength. Harness training is also an option to seriously consider. All this in 6/7 weeks in combination with a vegan diet should help return a modicum of my fitness I once had. It's the state of mind I must overcome!