You wouldn't have to straight up tell them that you are trying to lose weight. You could tell them you are eating healthy and exercising because you want to live a healthier lifestyle. Everyone's bodies are shaped differently, don't feel like you have to look like a model. God made you the way you are out of his own image and likeness. Also, don't be afraid to tell your parents the truth. Maybe you could exercise WITH your parents and help them lose some weight too!
Protein is a fundamental part of a healthy and balanced diet, but when you are in the daily grind, you may not get the proper amounts, especially if your goal is weight loss. Protein not only helps keep you satisfied for longer, it also contains amino acids like leucine, which has been shown in research to aid in maintaining muscle during weight loss. <<<