The invention relates to the use of one or several synthetic or natural furan alkyls for preparing a drug preventing and/or treating obesity or overweight. The use of one or several synthetic or natural furan alkyls for cosmetically treating local excessive weight is also disclosed. Said furan alkyls preferably correspond to formula (I), wherein identical or different R.sub.1, R.sub.2, R.sub.3et R.sub.4 are independently of each other a hydrogen atom, a C.sub.1-C.sub.35alkyl radical, C.sub.1-C.sub.35 alcenyl radical or a C.sub.1-C.sub.35 alcynyl radical, preferably C.sub.10-C.sub.22, wherein said alkyl, alcenyl and alcynyl radicals are substitutable and R.sub.1, R.sub.2, R.sub.3 are preferably a hydrogen atom.