The hypothalamus, at the base of the brain, regulates appetite.

The frontal lobe helps you make choices. Fried rice or steamed? Small milkshake or large?

Eating poorly contributes to the development of vascular disease, which can have a negative impact on longevity and cognitive functioning, says Dion Graybeal, a neurologist on the medical staff of Baylor University Medical Center at Dallas.

The brain's limbic system, which controls emotions, also is involved. This is why someone under stress tends to overeat.

SO YOU SHOULD: Avoid fast food. Drink alcohol in moderation. The old adage is: For breakfast, eat like a king; for lunch, like a queen; and for supper, like a pauper.

EXERCISE

Working out increases the activity in the frontal lobe of the brain, says neurologist Malcolm Stewart.

``You get the runner's high; that's endorphins. It's the body's reward system for exercise.''

Additionally, the motor system sends a signal that increases the amount of a hormone called brain-derived neurotrophic factor, or BDNF. ''It's like brain fertilizer, or Miracle-Gro, for memory cells,'' Stewart says.

''Research is being done -- it has been documented in rats and will soon be in people -- that shows physical exercise may be important in helping prevent Parkinson's disease, dementia as well as Alzheimer's'' says Stewart, who works with patients with both diseases. ``I tell everybody they need to become a jock.''

SO YOU SHOULD: Do a combination of stretching, aerobic and muscle-strengthening routines. One suggestion: Mix it up. Alternate cardio- and strength-training days for a full-body workout.

MENTAL GAMES

The part of the brain affected by enrichment activities may vary. For language-based activities, such as reading, the left side, or frontal temporal, is primarily involved.

For number games such as Sudoku, the right side, or parietal area, is involved. Listening to music can involve both sides.

SO YOU SHOULD: Get six to eight hours of sleep every night, Stewart says. Try to have a sense of hope about the future. Reduce stress by exercising, meditating or praying. Do puzzles. Listen to music. Reach out to others to make their lives better.

Sources: The Associated Press, CNN, BBC News,

bookologist.com, The Dallas Morning News