The phrase "to waste the calories" means using up or consuming calories from food on something that doesn't provide much benefit or value, such as eating unhealthy or unnecessary foods. Full definition
Don't waste your calories on foods that you can have all year long. (onnit.com)
But do nt waste your calories on things you do nt love. (health.com)
They came really fast within the first night on the diet though and did I read correctly that excess ketones are just wasted calories? (ketodietapp.com)