It's common knowledge that our metabolisms generally slow down as we age, making it harder to lose weight. But there's more to it than just that and it has to do with your muscles.

According to Stephen Anton, chief of the Division of Clinical Research at the University of Florida College of Medicine’s Department of Aging and Geriatric Research, the quality of muscle also starts to change from being mostly muscle fibers to a combination of fat and muscle within the muscle fiber. “After age 50, the process of your muscles being infiltrated by fat accelerates,” he says in a Men's Health article. Because of this, you may feel more easily fatigued, you lose muscle mass and it's easier for fat to pile on. This means you'll have to work extra hard to get that fat off and lose weight.

Here are nine tips to help you shed those pounds and keep them off:

• Eat more fruits and vegetables - low in calories and packed with fiber, they can keep you feeling full longer.
• Buy an Instant Pot and make bean stews - filled with fiber and protein, beans also feed the good bacteria in your gut which in turn can help protect your metabolism.
• Befriend your bathroom scale - check your weight every morning so you're on top of it if you start gaining.
• Focus on your food - eating on the go or while watching tv can cause you to overeat. Chew slowly and enjoy each bite.
• Stop drinking sugar - it's empty calories.
• Mix up your workouts - use different cardio equipment and try resistance and interval training too.
• Pick up a new sport - soccer, basketball and ultimate frisbee are particularly effective in burning calories, like interval training.
• Try intermittent fasting - restrict your food intake to certain hours of the day.
• Start practicing yoga - it can help you maintain mobility as you age, and its calming effect is helpful when trying to lose weight.

As always, it's important to check with a doctor before starting any new physical fitness routine, especially if you have any medical issues. You may also benefit from consulting a personal trainer.

If you're on any medications, and a lot of men over 50 are, be sure to check for weight gain as a possible side effect. If you feel like you've gained weight and have been actively trying to lose it with no luck, talk to your doctor. Also read this article from University of Rochester for common medicines that can cause weight gain, what causes it, how it's diagnosed, and what can be done. Sometimes medications can be changed to something else that may not cause you to gain weight, without affecting your health otherwise.

Good luck with your weight-loss goals!