You've likely heard over and over that the key to losing weight is reducing food intake. And exercise plus control of portion size is what's needed to keep weight off once you lose it.

That's technically true. But healthful weight loss isn't just about numbers.

You want the reward for all your hard work to be looking good and feeling strong — and that means you want to maintain and even build muscle as you shed excess pounds.

A new study published in the journal Medicine & Science in Sports & Exercise looked at the results of a six-month weight-loss program for postmenopausal women. It revealed that if you combine a protein-rich diet with exercise, you can maintain and build muscle strength while you lose weight.

But if you just opt for a high-protein diet without exercise, you will lose strength as you shed pounds. 

It's essential that any weight loss program be paired with 30-60 minutes of physical activity five or more days a week. That should include two weekly 20-minute resistance exercise sessions.

We also recommend you balance protein intake with healthy carbs, such as 100% whole grains and fiber-rich veggies and fruits.

Weight loss is not won by the speedy but by the consistent, committed, and controlled. To shed one to two pounds a week, reduce your calorie intake by 300-500 a day as you increase your exercise routine.

And don't let increased exercise fool you into thinking you can eat anything you want — it's still necessary to watch your calorie intake.