"Daily kilocalories needed = BMR x 1.9 Knowing one’s daily calorie needs may be a useful reference point for determining whether the calories that a person eats and drinks are appropriate in relation to the number of calories needed each day. The best way for people to assess whether they are eating the appropriate number of calories is to monitor body weight and adjust calorie intake and participation in physical activity based on changes in weight over time. A calorie deficit of 500 calories or more per day i s a common initial goal for weight loss for adults. However, maintaining a smaller deficit can have a meaningful influence on body weight over time. The effect of a calorie deficit on weight does not depend on how the deficit is produced — by reducing calori e intake, increasing expenditure, or both. Yet, in research studies, a greater proportion of the calorie deficit is often due to decreasing calorie intake with a relatively smaller fraction due to increased physical activity. Table 2 . Estimated Calorie Ne eds Per Day By Age, Gender, and Physical Activity Level* Estimated amounts of calories needed to maintain calorie balance for various gender and age groups at three different levels of physical activity. The estimates are rounded to the nearest 200 calorie s. An individual’s calorie needs may be higher or lower than these average estimates. Physical activity level* gender age (years) sedentary Moderately active active child (female and male) 2 – 3 1,000 – 1,200c 1,000 – 1,400c 1,000 – 1,400c female 4 – 8 1,200 – 1,400 1,400 – 1,600 1,400 – 1,800 9 – 13 1,400 – 1,600 1,600 – 2,000 1,800 – 2,200 14 – 18 1,800 2,000 2,400 19 – 30 1,800 – 2,000 2,000 – 2,200 2,400 31 – 50 1,800 2,000 2,200 51+ 1,600 1,800 2,000 – 2,200 male 4 – 8 1,200 – 1,400 1,400 – 1,600 1,600 – 2,000 9 – 13 1,600 – 2,000 1,800 – 2,200 2,000 – 2,600 14 – 18 2,000 – 2,400 2,400 – 2,800 2,800 – 3,200 19 – 30 2,400 – 2,600 2,600 – 2,800 3,000"