You've tried everything from dieting and calorie counting to exercise boot camp and weight loss apps — but the numbers on the scale just won't budge. Could there be something else sabotaging your efforts to lose or maintain weight?

Let's uncover some factors that could be holding you back from losing weight. Although you have the power to change a few of these factors, some are beyond your control. Either way, finding out why weight loss is challenging can be helpful, especially when coming up with a plan or deciding when to seek help for weight loss.

1. Lack of sleep

Your health suffers when you're sleep-deprived, and lack of sleep can affect your chances of losing weight, too. Research has shown that sleep deprivation can lead to increased cravings for high-carb foods and junk food.

When you're overtired, you may be more likely to reach for high-calorie beverages or a sugar fix for quick energy. You may also lack the energy and initiative to make healthy food choices.

"At the end of a long day you may not have enough energy to go for a walk or make a healthy meal, and the choices you make when you're tired and hungry can derail your efforts to lose weight," says Dr. Nabil Tariq, bariatric surgeon at Houston Methodist.

How to take control: Aim for seven to eight hours of sleep at night so you can function at your best during the day.

2. Yo-yo dieting

Yo-yo dieting is the cycle of losing weight only to gain it back — and it can take a toll on your health and make it harder to lose weight.

You may lose weight rapidly on a fad diet, but you're not just losing body fat. You lose lean muscle as well, which in turn decreases your metabolism. The problem with yo-yo dieting is that it's not sustainable.

"When you stop the diet and start eating normally again, the metabolism is lower than before, and the weight you regain is mostly fat," Dr. Tariq explains.

How to take control: Modify your diet in a way that's sustainable for the long term. You want to find solutions for managing your weight that will work for the rest of your life, not just dropping pounds for a special event or a few months.

3. Balancing gym time with meal-planning time

Have you been toiling away at the gym without losing any weight? If this sounds all too familiar, it may make sense to spend more time and energy on meal planning.

"Weight loss is about food intake more than anything else," Dr. Tariq explains.

Exercise is good for your overall health and longevity, but it's only a small component of weight loss. The majority of weight loss comes from making dietary changes and consuming fewer calories than you can burn in a day.

How to take control: By spending 30 minutes preparing a healthy meal, you can avoid consuming an extra 700 to 800 calories, compared to eating fast food or takeout. When you combine a healthy diet with exercise, it's a win-win!

4. Aging

Controlling your weight can be an uphill battle as you age. Even if you're exercising and eating right, the pounds can still creep up.

"As you get older, your metabolism decreases and your body doesn't burn as many calories," Dr. Tariq says.

In addition, you may lose muscle mass with age, and the problem is compounded if you're less active. It all adds up to a recipe for weight gain.

How to take control: Cut back on portion sizes of higher calorie foods and increase portion sizes of lower calorie foods like non-starchy vegetables, such as broccoli, cauliflower, green beans, okra, etc. Try to exercise for 30 minutes every day — going for a walk is a great way to start.

5. Medications

Did you know that weight gain is a side effect of certain medications? Some medications taken for depression, inflammation, thyroid disorder or other conditions can make it difficult to maintain or lose weight.

These medications may cause you to feel hungrier, burn calories slower or retain extra fluids. It's important to continue taking your medications as directed by your doctor, but don't hesitate to ask about alternatives.

How to take control: Talk to your doctor if you have questions about how your medications may be affecting your weight.

6. Genetic influences

Genes can influence appetite, metabolism, body-fat distribution and more, but genetic influences don't tell the whole story. Environmental factors including eating habits formed in childhood, family and social connections, ways you cope with stress and other psychological factors can have an even greater impact on your weight.

How to take control: If you've struggled to lose weight most of your life, you may want to consider finding a weight management team that's dedicated to offering the support, tools and education needed to lose weight.