Here is a completed version of the passage with the appropriate words filled in:
A plant-based diet Following a diet consisting of plant foods only can have a profound effect on the body and mind, especially on teenagers who still GROW and developing. On the positive side, a well-planned plant-based diet rich in fruits, vegetables, whole grains, nuts and seeds can bring many health benefits, INCLUDING increased energy levels, improved digestion and reduced risk of chronic diseases. However, if you eat incorrectly, this type of diet can also lead to a deficiency of nutrients, especially vitamin B12, iron and omega-3 fatty acids, which ARE FOUND in animal products. Teenagers may experience fatigue, weakness or even problems concentrating if their diet LACKS essential nutrients. Ultimately, switching to a plant-based lifestyle may be a worthwhile choice, but it is extremely important for young eaters to educate THEMSELVES and make sure that they receive all the necessary nutrients to maintain an active lifestyle and overall well-being.