Skinnies down is a phrase often used to describe weight loss and is a bit colloquial in nature. Synonyms for this term can include phrases like "lose weight," "trim down," or "slim down." Other similar phrases could be "shed pounds," "drop some weight," or "reduce body fat." In more formal language, words like "reduce" or "decrease" could be used to describe this process. Ultimately, the way in which one chooses to describe their weight loss journey may come down to personal preference, but there are certainly many different ways to express the idea of "skinnies down".