if then elif

[Shawn Minisall]

I just learned about if, then elif statements and wrote this program.  
The problem is, it's displaying all of the possibilities even after you 
enter a 0, or if the fat grams are more then the total number of 
calories , that is supposed to stop the program instead of continuing on 
with the print statements that don't apply.  Any idea's?  thanks

    #Prompt for calories
    cal = input("Please enter the number of calories in your food: ")

    #Prompt for fat
    fat = input("Please enter the number of fat grams in your food: ")

    #Input validation
    if cal or fat <= 0:
       #Display message
        print "Error.  The number of calories and/or fat grams must be 
positive"
        print

    else:
    #Calculate calories from fat
        calfat = float(fat) * 9
       
    #Calculate number of calories from fat
        caldel = calfat / cal
 
    #change calcent decimal to percentage
        calcent = caldel * 100

    if calfat > cal:
        print "The calories or fat grams were incorrectly entered."

    else:
    #evaluate input
        if caldel <= .3:
            print "Your food is low in fat."
        elif caldel >= .3:
            print "Your food is high in fat."

    #Display percentage of calories from fat
        print "The percentage of calories from fat in your food is %", 
calcent

Here's an example of the output...

Please enter the number of calories in your food: 50
Please enter the number of fat grams in your food: 30
Error.  The number of calories and/or fat grams must be positive

Your food is low in fat.
The percentage of calories from fat in your food is % 0.0

It was supposed to print The calories or fat grams were incorrectly 
entered since the calories from fat was greater then the total number of 
calories.