public decimal getNutrientIngredientSumForDate(DateTime date, IEnumerable<UserIngredient> userIngredients, Func<Ingredient, decimal> valueToSum) { decimal sum = 0; var userIngredientsInDate = from u in userIngredients where u.Date.Date == date select u; foreach (var userIngredient in userIngredientsInDate) { sum += userIngredient.GetActualCalorieCount(valueToSum); } return sum; }