I'm impressed with the way utilized the long strip comic style with this chapter. Changing the perspective while scrolling down during the fight was really intuitive.
@Seamew i think there has been a 2 month time skip, and some of the vegetable there are more effective to help loose weight than anything on earth (but they taste like shit)
@Seamew I think you have to just assume it passed a lot of months for that to happen. Remember he is not just doing exercise to lose weight LOL. The exercises were more to motivate Lena and for him to train his body to be flexible and agile to make physical attacks as wee see happening in this chapter.
The trick to lose weight is the herbs he is eating. Now that he has his ranked chef back home, I am sure she is doing a better job in cooking the herbs while giving them a better taste so he can eat more and increase his metabolism to have a faster fat reduction.