No, its not related to food intake,.
White spot ...it may be due to lot of reasons,
Like ?Pitryiasis alba(due to atopy) where the patch looks hypopigmented with scaling, this most common..
? Pre-vitiligo or vitiligo (Depigmented skin patch) auto immune disorder..
?Hansens (white patch without sensation or decreased sensation) infection.
?it may due due post inflammatory hypo or depigmented patches...(Due trauma, post burns..etc).
Next Steps
Consult a near by dermatologist for better evaluation & treatment.