Meal prepping can certainly help with your weight loss goal because it can help you stay organized, use healthier ingredients, and track your progress long-term. Weight loss is a personal journey, and therefore your approach could depend on the information you read or guidance you are following. However, the key to meal prepping and losing weight is mastering portion control, which can help you stay on top of your caloric intake, which is the key to losing weight. In a similar vein, if you wanted to gain weight, you can portion control accordingly to the number of calories you need.