You are finally ready to get off the couch and clean up your diet. Maybe you want to lose weight, improve your health or just feel better. But where to start? You know that exercise is important, but so is diet, so which should you prioritize? It depends on your health goals.

If your goal is weight loss, focus on diet. If you exercise but don’t restrict calories, it is very difficult to lose weight. Consider this: An hour of vigorous basketball burns about 440 calories — the same amount in a McDonald’s double cheeseburger. Cutting 500 calories a day from your diet is more effective and easier to do consistently. Start by cutting back or eliminating sugary or processed foods. Add more plant foods — fruits, vegetables and whole grains — to receive essential nutrients and help keep you full.

If your goal is to increase energy, focus on diet. True, exercise can give you an immediate surge of energy. But smart eating will provide a steady fuel supply throughout the day. This helps keep your blood sugars balanced, avoiding those highs and lows that can sap your energy. Plus, regular fuel to your brain will help keep your mood and energy levels stable. Try to eat every three hours. Eat your three regular meals, plus two to three snacks of around 200 calories each in between. Don’t forget to drink enough water. Mild dehydration can leave you feeling sluggish.

If your goal is to decrease heart disease risk, focus on exercise. For heart health, being fit is more important than the number on the scale. Exercise helps with weight control, but it also lowers stress levels, lowers bad cholesterol, increases good cholesterol, lowers blood pressure, lowers glucose levels and increases blood flow. You need 150 minutes of moderate cardio exercise or 75 minutes of vigorous exercise every week, plus two days a week of resistance training.

Both types of exercise make your heart pump more blood, strengthening it. Sitting less throughout the day is important, too. Sitting for long periods negatively affects how the body metabolizes glucose and lipids. Sit for no longer than two hours at a time, taking a 10-minute break before sitting back down.

If your goal is to keep your mind sharp, focus on exercise. Regular exercisers have fewer of the abnormal protein brain deposits that have been linked to Alzheimer’s disease. Studies show that people who are fitter at midlife have a 36-percent-lower risk of developing dementia later in life than their less-fit peers. Aerobic exercise and strength training are both important. And, diet also impacts mind health.: Choose foods rich in fatty acids and low in refined sugar.

If your goal is to improve your body image or libido, focus on exercise. All types of exercise make you feel better about yourself. Yoga is one of the best exercises, especially for women, in improving self-image. It helps lower stress and anxiety and makes relaxation and focusing easier. Of course, the best bet for a healthy life is to combine both exercise and a nutritious diet. To maintain or lose weight, you must burn more calories than you eat every day. Exercise will help ensure that the weight you lose is fat instead of muscle. The National Weight Control Registry, which follows more than 10,000 Americans who have lost weight and kept it off, shows that just 1 percent of people kept the weight off with exercise alone. Ten percent succeeded with diet alone, but the majority, 89 percent, used both exercise and diet. The latest report from the Center for Disease Control and Prevention shows that only 23 percent of adults between the ages of 18 and 64 meet the recommendations for exercise and strength training. With nearly 40 percent of Americans now obese, we are not eating very well either.

Any small diet improvements you make coupled with increased movement will help your overall health. It is never too late to start.

Anita Marlay, R.D., L.D., is a dietitian in the Cardiopulmonary Rehab department at Lake Regional Health System in Osage Beach, Mo.