I'm eating 4500 calories everyday and I just can't gain weight, I'm stuck at 80kg o will occasionally see 81kg on the scales but then it will go back down to 79kg or 80kg . I don't understand why I need so many calories to gain weight surely 4500 should be enough to gain weight . My maintenance calories is about 2400 if I use calorie calculators . What could be stopping me from gaining weight?