Smiling vs. Frowning and the muscles needed for both is an indicator that smiling is better for a person :-)
I heard it takes like 43 muscles to frown :-( and 17 to smile :-)
The link below gives a bunch of different perspectives.
http://www.snopes.com/science/smile.aspQUOTE (little koshka @ Jan 3 2009, 11:49 AM)

1. Stop drinking soda (diet and regular) - drink water instead.
2. Eat more fresh vegetables and fruits.
3. Eat less red meat and more fish and lean poultry.
4. Cut back on your sugar intake.
5. Avoid fast food.
6. Avoid highly processed foods - fresh is best. Avoid processed or packaged foods with a gazillion ingredients that you can't pronounce.
7. Avoid simple carbohydrates (processed white items) and choose whole grain complex carbohydrates instead.
8. Get at least 7 hours a sleep a day.
9. Excersise daily.
10. Smile.