Lean hamburgers are used as a substitute for normal hamburgers so as to reduce the harmful substances in the normal hamburgers. These include things like fat and other substances, but most importantly sodium. Since there is already low levels of sodium in lean hamburgers, limiting them would not make much of a difference.
If you eat foods that are high in sodium, the amount you consume will either not change or increase. You must eat more fruits and vegetables to lower your sodium intake.
