Forget your horoscope--the answers might be in your blood.

Oh, sorry--did you think that you determined your personality and behavior?

According to a popular Japanese belief, some things are just in our blood. And while blood-type profiling, or ketsuekigata, isn't scientifically proven, millions of people swear by it to guide a healthier lifestyle--there's even a diet plan based on it. So what's your type?

Type A

Key traits: You're responsible, anxiety-prone and a bit of a control freak. You're also introverted and sensitive.
Optimal diet: Vegetarian and low-fat.
Best workouts: Low-impact aerobics, stretching and dance.

Type B

Key traits: A strong individual, you set your own rules and are outgoing and charming.
Optimal diet: Balance plant and animal proteins.
Best workouts: Yoga, brisk walking or swimming.

Type O

Key traits: You seek attention and are energetic, confident and outgoing. You also have a competitive streak.
Optimal diet: High-protein (especially meat) and low-carb is best.
Best workouts: Get your heart racing with intense cardio.

Type AB

Key traits: Unpredictable and mysterious, you're always changing, but are rational and keep a cool head.
Optimal diet: A little of everything.
Best workouts: Thought-inducing exercise like golf, tai chi or yoga.