When David Archuleta sings "A little spark to get through the night/ Could be enough to see a new day/ 'Cause a little goes, it goes a long way," he is describing perfectly just how little it can take to turn your life around.

If you're 65 to 79, sedentary and obese, a randomized, controlled trial of 160 adults published in the journal Circulation found that cutting as few as 250 calories a day from your diet and doing aerobic exercise with a trainer for 30 minutes, four days a week for five months is enough to help restore flexibility in a previously stiff aorta (an indication of plaque deposits and heart attack and stroke risk), reduce high blood pressure, and help you lose 10% of your body weight.

Increasing the calorie restriction didn't improve outcomes; neither did exercise without moderate calorie cutting. Too much or too little isn't your goal — it's persistence and consistency.

A good way to figure out how to cut 250 calories from your daily diet is to write down everything you eat for a week. Then figure the calorie count for each item (check out nutritiondata.self.com) and make choices with the aim of eliminating added sugars, unhealthy fats, and red meats.

If you're sedentary, it can be tough to start exercising. So try walking — aiming for 30 minutes four days a week. Then consider pool aerobics, joining a class, or working with a trainer to help you establish an exercise routine.