A sustainable and effective meal plan for losing weight should prioritize balanced nutrition and portion control. Incorporate a variety of whole foods, like lean proteins, vegetables, fruits, and whole grains, to ensure you receive essential nutrients. Limit processed foods, sugary beverages, and excessive fats. Maintain consistency and create a calorie deficit through portion control while focusing on long-term lifestyle changes rather than extreme diets. Consult a healthcare professional or registered dietitian to tailor a plan to your specific needs and monitor your progress.