So according to http://www.turkishairlines(dot)com/e...eal-selection/ "you can easily select your main course on our website or mobile app before your travel." and also:

• A week before your flight, you can check photos, and choose from delicious dining options that will be served to you on any and all intercontinental flights departing from Istanbul. We kindly remind that you make your meal selection at least 48 hours before your flight.
• Dining options vary from flight to flight.
• Your meal selection may not available due to operational reasons.
• You can make your meal selection using your ticket information, via our website or mobile application.
• Our meal selection service is currently only available on flights from Istanbul to Atlanta, Bangkok, Bogota, Boston, Cape Town, Caracas, Dallas, Denpasar, Durban, Guangzhou, Caracas, Hanoi, Havana, Hong Kong, Houston, Jakarta, Johannesburg, Kuala Lumpur, Los Angeles, Madagascar, Manila, Maputo, Mauritius, Mexico City, Miami, Montreal, New York, Newark, Osaka, Beijing, Phuket, San Francisco, Shanghai, Sao Paulo, Ho Chi Minh, Seattle, Seoul, Singapore, Chicago, Taipei, Tokyo, Toronto, Vancouver, Washington DC and Xi'an.

We are flying business from Istanbul to Mexico City.
Have any of you been able to pre book a meal, and if yes, how?