I am a boxer, my height is 5ft7 & i weigh 74kg, i find it very hard to lose fat, i am only having 150g of carbs per day, is this my natural weight?

Yes: Your fat composition is linked to your genetics, hormonal balance and diet. If the fat is mostly on your trunk, get a blood analysis with your physician to look at your hormones and your vitamin d levels (actually a hormone that interacts with Insulin and thyroid and growth hormone). Some protein supplements strain the kidney function, and require care in your efforts at weight control.