How many calories on average does a recipe that comes from "Produce for Better Health Foundation and 5 a Day" contain?
Produce for Better Health Foundation and 5 a Day is a source of recipe; calculation = DIVIDE(SUM(calories), COUNT(recipe_id))
SELECT AVG(T2.calories) FROM Recipe AS T1 INNER JOIN Nutrition AS T2 ON T1.recipe_id = T2.recipe_id WHERE T1.source = 'Produce for Better Health Foundation and 5 a Day'