How to stop my rib bones showing??

okay i used to be around 90 kilograms and i'm 6 foot 2. most of which was fat. So i decided to loose weight so i cut out desserts etc i lost weight and it plateaued around 75kg so i did exercise and got down to about 73kg my ribones didnt show at this stage. however i had love handles so i did alot of jogging on the treadmill at a high incline so my legs are toned and my legs arent a big build neither are my arms so i neva had fat there. So as i exercised and stoped eating carbs my ribs potruded only the first two closes to my collar bone. i have broad shoulders and i can build muscle pretty easily considering the litlle regularity and amount of reps and sets i do in my pushups. so recently ive been trying to gain weight and i just cant get the weight to cover my rib bones. they dont show that much when i wake up in the morning but theyre more visible at night how can i fix this cause i still wanna do cardio to get rid of extra fat on my midsection?