Depends on the definition.
Someone who sometimes discover some racist trait in himself and is appalled is no racist.
Scientists say that differences in body are not that much in humans to speak of "races". There have been different human races ("us", i.e. homo sapiens sapiens, the Neanderthal man, the Denisova man, the Flores man and possibly another race in Africa, which is suspected because of genetic traits in modern humans but is has to be discovered). Neanderthal genes, Asians less Neanderthal and more Denisova genes, Africans neither genes), but modern humans are a single race.
Discovering differences, whether in body (East African people are good long distance runners, because of their long legs, Innuits are more adapted to cold climate, ...) or in culture is no racism. The racism starts when these differences are used to view some people "superior" to others. Every person has the same rights, there should be no discrimination.
Often racism claims "racial" differences which are not existent. The most prominent example is the so-called Jewish race.