Final answer:
Cross-training is the best way for a dietitian to control labor costs.
Step-by-step explanation:
To implement an effective staffing plan and adhere to budget constraints, the dietitian can ensure that labor costs are controlled best by cross-training. Cross-training refers to training employees to perform multiple tasks or skills, which allows for flexibility in staffing and reduces the need for hiring additional staff. By cross-training the dietitian and other staff members, the organization can better allocate resources and minimize labor costs.