context: The second half of your life can bring some of your most rewarding decades. You may be more confident than your younger self. You gain wisdom and patience. Sure, your hair sprouts more grays and your face sports more lines. But you can grow older with your body and mind as healthy as they can possibly be. Here are science-backed secrets to do just that. It's more a way of eating than a formal diet. You load up on veggies, fruits, whole grains, nuts, and low-fat dairy. You eat less fatty meats, butter, sugar, salt, and packaged foods. Many studies have found that this diet can help you live longer and protects against heart disease, cancer, Parkinson's, and Alzheimer's disease. Researchers believe one way it works is by physically changing parts of your chromosomes linked to age-related diseases. Aim for 30 minutes every day. If that's too much, break it up into shorter strolls. Regular exercise -- especially if you do it briskly enough to feel a little breathless -- delivers huge health benefits. It help keep brain cells healthy by delivering more blood and oxygen. In fact, research suggests aerobic exercise may delay or improve symptoms of Alzheimer's disease. It also helps: Control your weight Boost your mood Keep bones and muscles strong Helps you sleep better Makes you less likely to get heart disease, type 2 diabetes, high blood pressure, and high cholesterol Loneliness is harmful to your health. If you feel lonely -- whether you live alone or with someone, have lots of friends or none -- you are more likely to get dementia or depression. Seniors who report feeling left out and isolated have more trouble with everyday tasks like bathing and climbing stairs. They also die earlier than less-lonely folks do. Researchers found that lonely people have higher levels of stress hormones that cause inflammation, or swelling, linked to arthritis and diabetes. Another study found more antibodies to certain herpes viruses in lonely people, a sign of stress in their immune system. So stay or make friends. Do volunteer work or simply help someone in need. Just connect. It's an easy way to eat your way to better health with every meal and snack. Swap out your white bread for whole grain. Add kidney beans to your soup or apple slices to your salad. Fiber fills you up and for longer. It cuts your cholesterol levels and lowers your chance of heart disease, type 2 diabetes, and colon cancer. It also helps you avoid constipation, which is more common in older adults. After age 50, men should aim for 30 grams of fiber a day and women should get 21 grams a day. Tobacco kills. It harms almost every organ in your body. Cigarettes, chewing tobacco, and other products with nicotine cause heart disease, cancer, lung and gum disease, and many other health problems. It's never too late to quit. Your body begins to heal within 20 minutes of your last cigarette. Your chance of a heart attack goes down right away. In a year, your odds of heart disease drop by half. You'll also live longer. Ask your doctor for help. This gentle Chinese exercise combines slow movements and deep breathing. It's like meditating while you move. Tai chi may help older people avoid falls, a top cause of injury among seniors. It also can: Ease stress Improve balance Strengthen muscles Increase flexibility Lessen arthritis pain It's often better to get your nutrients from food, not a pill. And you usually don't need special supplements aimed at seniors. After age 50, your body does need more of some vitamins and minerals from foods or supplements than before. They include: Calcium (to keep bones strong) Vitamin D ( Most people get it from sunlight, but some seniors may not get out enough.) Vitamin B12 ( Older people have trouble absorbing it from foods, so you may need fortified cereals or a supplement.) Vitamin B6 ( It keeps your red blood cells strong to carry oxygen throughout your body.) Tell your doctor about any supplements you take so you can avoid bad interactions with any medications or treatments. Life tests us in many ways. Loved ones die, layoffs happen, and health problems can mount. But positive thinking can be a powerful ally. When you choose to be optimistic and grateful, your mind and body respond in kind. People with a rosier outlook live longer and have fewer heart attacks and depression than more negative people. Positive emotions may even lower virus counts in people with HIV. You can learn to be optimistic. It just takes time and practice. Things you can do include: Smile, even fake smile. It can help lower stress. Reframe. Spin your thoughts to the good things instead of dwelling on the bad. Keep a gratitude journal. Do good things for others. Surround yourself with people who boost your spirits. Accept things you can't change. Insomnia is common in older adults. It's when you have a harder time falling and staying asleep. It helps to wake and sleep on schedule every day. That can help keep your body clock in sync so you get the sleep you need. Also try and: Keep your bedroom dark. Turn off your TV, cell phone, and laptop. Avoid caffeine or alcohol in the evening. Don't nap longer than 20 minutes during the day. Ask your doctor if any of your meds might be keeping you awake.