Fat

hit the gym mate

if you eat less calories than you burn, you lose weight
if you eat more calories than you burn, you gain weight

it's that simple, man

Dammn, I weigh like 45kg, and I can eat anything without getting any more fat
Some people say, that I'm lucky, or something, but I don't believe that, because I drive my mtb everyday, every season, as I have been doing for something like 9 years.. It call it my hobby, as I do it everyday, because I just want to go out and do something, and the best way of transportation for me is using a bicycle, so yah..
So.. I would suggest going to the gym, riding a bicycle or going running! Always remember - No pain, no gain!
I personally think, that going to the gym, getting sore n stuff is a lot better, healthier and also faster to lose weight, than starving yourself, also you get fit.

Your weight is not healthy anymore rofl.

As @Flengo said. It's due to your eating habits. I tried excercizing and lifting but I never lost weight.

Due to eating habits.

I run every morning. It helps me keep myself in shape. If you want to lose weight, then you need to completely overhaul your diet and workout. In addition to aerobic exercise, you still need strength training. You can go to the gym, but I would recommend some kind of sport. It's more fun.

can someone live with under 70 kilos?

Eat better, maintain good diet, cardio. I do all of em and keep in lean shape.. it does work.

how tall are you tho