Why my body is not gaining weight?

To few calories!: Assuming you are not hyperthyroid, the most common cause is eating too few calories! although meats, poultry, fish, eggs, cheese, nuts are the most nutrient dense foods, if you are a vegan, or have dietary preferences that take you away from these food sources, you might have problems. I always encourage consumption of protein and good fats! but your goal is to put on muscle, not fat.

Taking A Look At...: ..How much you eat, relative to your body's need ("bmr") for calories, will let you know if your intake is enough. For a woman, a general formula might be: 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age) = BMR (basal metabolic rate). Factors such as age, activity level, disease states, medical issues can affect this value..Up or down.. Too.