If the nutritional data for a recipe appears incorrect there are two things to check. First, look at the number of servings. Sometimes recipes are imported with the wrong serving information, other times the serving size might not exist so Modernmeal defaults the servings to 1. Nutritional information is based per serving, so make sure the serving size in the recipe is correct then re-import the nutritional data by pressing the import button. 
Secondly, the most accurate way to get nutritional information will always be to explicitly define the weights or price volume of each ingredient, (e.g. 100g shrimp, 1 lb. turkey, 1 cup diced onion). You can use the 'review ingredients' feature to make sure that 1) we properly understand the recipe ingredients and 2) make sure the unit of measure is clearly defined like in the example above.
If you still have issues please contact support.