Final answer:
The missing word for a healthful diet is 'moderation,' which along with balance and variety, forms the foundation of a healthy diet. These principles ensure an adequate intake of nutrients, proper calorie control, and the inclusion of a diverse range of whole foods.
Step-by-step explanation:
The three key words to a healthful diet are balance, variety, and moderation. A healthful diet includes the five key factors which are: adequacy, balance, calorie control, moderation, and variety. To achieve balance in your diet, it is essential to consume the right proportion of nutrients without overemphasizing one at the expense of the others. Calorie control ensures the energy gained from food matches the energy spent in daily activities. Moderation is crucial, meaning you should avoid eating too much or too little of any food or nutrient. Variety involves including different foods from each food group to secure adequate nutrient intake and promote health.
A healthy diet should focus on whole foods, which provide essential vitamins, minerals, proteins, carbohydrates, fats, and fiber. It's also important to limit processed foods high in sugar, salt, saturated and trans fats. Tools such as MyPlate and MyPyramid, along with reading food labels, can assist with making informed choices and creating a balanced eating plan that incorporates a diverse range of foods, textures, and flavors, thus ensuring that one's diet is both interesting and nutritious.