List everything you ate yesterday. Then go to an online nutrient tracker such as the USDA National Nutrient Database, or What’s in the Foods You Eat, and list the sodium content next to each food. Remember to break down foods into their various parts and look up the sodium content for each; for example, for a sandwich, look up the sodium content for the bread, cheese, meat, etc. You can also consult the nutrition labels on any packaged food you ate for the sodium content.