Body Composition Measurement. The most accurate assessment of your ideal weight takes into account the composition of your body. How much of your weight is lean body mass (muscle and bone) and how much is body fat. For optimum health, body fat should be no more than 20% of total body weight for men and 30% for women.
Fat is produced by the body when an excess intake of calories in the form of food or drink occurs. When the diet provides the body with more calories than it needs for general maintenance and its current level of physical activity, this excess energy is stored in the form of body fat.
Females tend to accumulate fat around their thighs and hips and males accumulate fat around the midriff.
An increase in regular exercise will help to increase your calorie expenditure. The more physical activity you do the more calories you will burn. Accordingly, if you increase your physical activity, and do not increase your intake of food, you will draw the extra energy needed from your stored body fat.