I found it intriguing because it relates psychology, mood, and behavior with metabolic syndrome and I teach young college students about blood glucose regulation and diabetes prevention. I was wondering about its validity. Many of them have this kind of symptoms, and many more than 20 years ago report getting suddenly very sleepy after meals and (fewer) having signs of low blood glucose about 2-3 h after a meal (slight muscle tremors in hands and legs, urge to eat, irritability if prevented, as well as a relative with diabetes. 20 years ago, I might have a maximum of 5 out of 25 in a class, now, I sometimes have 25/25. I also recall some of those symptoms in myself when I was insulin resistant many years ago.

my students are generally slim, as they are studying fashion and related matters. Most of them are on relatively high protein diets, often with only 1200-1600 calories according to nutrition analysis I do in my nutrition classes. Unfortunately, I don't have the ability to do blood tests. To validate the questionnaire would probably be much easier where one already tests blood glucose and insulin.

Since I created the Nutrition Behavior Inventory and published it in 1980, I thought it would be helpful to answer the question. Yes, it has been validated. The citation is: Benko CR, de Farias AC, Cordeiro ML. Eating habits and psychopathology: translation adaptation, reliability of the Nutrition Behavior Inventory to Portuguese in relation to psychopathology. J Brasileiro de Psiquiatria(Brazilian Journal of Psychiatry). 60(4), 1-12, 2011.

In addition, it has been used by many researchers. For example, this paper in BMC Pediatrics: Potential link between caffeine consumption and pediatric depression: a case-control study. BMC Pediatrics. 11, 73-78, 2011.] I'm sorry that I did not see this question six years ago when you posted it, as the answer to your question could also have been found using Google since the paper on its validation appeared in 2011 and the NBI was included in the title.