The invention is concerned with novel substituted piperidine derivatives of formula (I) wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and X are as defined in the description and in the claims, as well as physiologically acceptable salts and esters thereof. These compounds inhibit L-CPT1 and can be used as medicaments.