““and around an hour each day spent cycling”.....Uh, I suspect this had as much to do with it as the diet.”
3Kg of potatoes is about 2300 calories.
Cycling for an hour probably burns about 400 calories.
The human body, just to function (i.e. you lay there and do nothing while awake), needs about 2,000 calories.
Overall, he did exactly what you need to do to lose weight ... burn more calories than you consume. It isn’t rocket science and I’m sure morons like FoodBabe would tell him those potatoes have all sorts of disease ridden non-organic filth if she hadn’t endorsed them.
Weight loss scams make me sick. There are *always* exceptions to a rule when it comes to people, but a vast majority of people will lose weight if they burn more calories than they consume.
It’s a pretty simple formula.