Do you think there are poses and yoga practices to gain weight? Should I do just meditation and no asana:) ?
You could try padmasana while eating a large Bigmac menu 
A complete yoga practice including asana, pranayama, meditation, lifestyle, nutrition, and applied philosophy should balance the student and therefore bring them to an optimal weight (for them) such that they may live life with great joy.
[QUOTE=Arno;44240]You could try padmasana while eating a large Bigmac menu :p[/QUOTE]
I have not asked hot to get sick:0 but how to gain weight:)
I do alot of physical activity and can not eat so much…especially sattvic diet
[QUOTE=CityMonk;44282] I have not asked hot to get sick:0 but how to gain weight:)
I do alot of physical activity and can not eat so much…especially sattvic diet[/QUOTE]
Follow what the sages said thousands years ago.
Wake up early in the morning.
Do meditate.
Then perform Anulom-Vilom and Kapalabhati Pranayama.
Practice Surya Namaskara (Sun Salutations)
Then perform Padmasana, Siddhasana, Bhujangasana and Dhanurasana.
Take a warm fresh bath.
Do this and if you are thin then you will surely gain weight as well as if you are overweight you will reduce excessive fats.
Yoga is so natural it will find what your body lacks and supply exactly that.
You just do yoga and every thing will be cared by Yoga itself.
Hope this helps.
Thanks,
Kindest to you,