It is a phase!
Your job as a parent is to buy the right food, prepare it nutritiously and serve it creatively.
Leave the rest up to your child. How much they eat, when they eat, and if they eat is their responsibility. After a year of rapid growth (the average one-year-old has tripled birth weight), toddlers gain weight more slowly. Aim for a nutritionally-balanced week, not a balanced day. Offer, don't force.