TPB can also be applied in area of nutrition-related interventions. In a study by Sweitzer, "et al", TPB-related behavioral constructs guided the development of intervention strategies. TPB was applied in such a way as to encourage parents to include more fruit, vegetables and whole grains (FVWG) in the lunches they packed for their preschool children. Knowledge/behavioral control, self-efficacy/perceived behavioral control, subjective norms, and intentions were assessed. The researchers observed in the TPD-oriented intervention a significant increase in vegetables and whole grains in the lunches parents prepared for their children.