Diet Sleuth is one of the most complete diet software programs available for both Windows and the Macintosh. It is a nutritional database and personal health logbook.

Diet Sleuth allows you to keep track of what foods you eat each day, and their nutritional value. For each day, you select the foods you have eaten, and the number of servings of each. Diet Sleuth will automatically calculate your caloric intake, fat grams, carbohydrates, fiber, protein, cholesterol, along with sodium, potassium, and calcium. You can select from over 5000 different foods from 21 categories, including fast food, lunchmeat, junk food, seafood, and baby food.

In addition to the included food groups, you can create and edit your own foods in a separate catagory. You can also create a category of favorite foods to quickly access commonly used foods. In addition, you can enter nutritional information for your own custom foods. Diet Sleuth users can exchange custom foods with each other.

A built-in Recipe Editor allows you to quickly enter a custom recipe, with the nutritional information automatically calculated, based on the ingredients.

Diet Sleuth can also keep track of your daily weight, and calculate your EER or Estimated Energy Requirements, which is an estimate of how many calories you burn each day, based on various factors. This lets you estimate how much weight you can expect to lose on a given day, based on your caloric intake.