In the chapter II : THE FIRST STEPS of Raja-Yoga non-killing is one of the requirement of Yama step
Râja-Yoga is divided into eight steps. The first is Yama — non-killing, truthfulness, non-stealing, continence, and non-receiving of any gifts. Next is Niyama — cleanliness, contentment, austerity, study, and self-surrender to God. Then comes Âsana, or posture; Prânâyâma, or control of Prâna; Pratyâhâra, or restraint of the senses from their objects; Dhâranâ, or fixing the mind on a spot; Dhyâna, or meditation; and Samâdhi, or superconsciousness. The Yama and Niyama, as we see, are moral trainings; without these as the basis no practice of Yoga will succeed. As these two become established, the Yogi will begin to realise the fruits of his practice; without these it will never bear fruit. A Yogi must not think of injuring anyone, by thought, word, or deed. Mercy shall not be for men alone, but shall go beyond, and embrace the whole world.
Does it mean a person should avoid non vegetarian food to be successful in Raja Yoga? Although the above statements support it but I found no explicit statements of avoiding non vegetarian food.