Final answer:
Diet can influence gene expression, and therefore the statement is false. Not all genes are expressed in every cell, and diet can significantly affect which genes are turned on and off, influencing health outcomes.
Step-by-step explanation:
The statement is false. Diet can indeed influence gene expression—the making of proteins. While every cell contains the same DNA, not all genes are expressed in every cell. Gene expression is regulated and can be influenced by various external factors including diet. Different cells express different genes to produce the proteins they need for specific functions. Therefore, certain dietary components can modulate gene expression and affect protein synthesis. By influencing gene expression, diet can play a crucial role in health and the development or prevention of lifestyle-related illnesses.