It adds noise, but you compensate for that noise as you go. If the noise causes you to take in too many calories one week and gain weight, then you can make tha

It adds noise, but you compensate for that noise as you go. If the noise causes you to take in too many calories one week and gain weight, then you can make that up by reducing your calories the next week. If you lose weight too quickly, you can increase your intake. As long as the calorie estimates are within a reasonable range of the real value, it shouldn't matter much in the long run.