15kg in 2 months is silly levels of loss. I hope you were very very overweight.

1kg of fat is 7,700 kcals. To lose 2kg a week for 8 weeks you need to find a deficit of 2,200 kcals per day the entire time. A large inactive man will have roughly a basal metabolic rate of ~2,200 kcals per day, so you need a deficit of your BMR per day to be losing this level of weight. This is very very hard to do.

Do not try this at home. Do not try this on your own.