1. Medical Issues - If you're having trouble losing weight, visit your doctor to ensure that your thyroid is functioning properly. This requires only a simple blood test.  One classic symptoms of a thyroid issue is weight gain because the thyroid gland controls your metabolism. Click here to find out if you are at risk for thyroid disease. Secondly, certain medications like hormonal medications (birth control, menopause medications), antidepressants and even diabetes medications have been known to cause weight gain. Ask your doctor if your prescription medications may be preventing you from losing weight and if there are any alternatives.

2. Stress - Not only is stress damaging to your mental healthy, but it also takes a toll on your body. Living in a constant state of stress boosts the production of a hormone called cortisol, which makes your body hold on to fat as well as crave sugary and fatty foods. Even worse, the hormone tells the body to deposit more fat in your midsection, which is the most dangerous type of body fat. Find out if you're overly stressed here.

3. Diet - We all know that you have to eat healthy to lose weight, but what happens when you eat what you believe to be healthy foods and you're not seeing results? It's very easy to eat the wrong foods, even when you think you're eating healthy. For example, many food companies push 100-calorie snack packs, fat-free and sugar-free foods. The problem is that these foods are still highly processed and not filled with enough fiber and protein to keep you satisfied. The trick is to focus on eating a wide variety of whole, unprocessed foods.  Here's a guide to learning more about eating whole foods.

4. Sleep - Numerous studies have shown that skimping on sleep can cause weight gain. While the reason why is not completely known, it's thought that too few hours of sleep can slow down your metabolism. Not catching those Z's can lead to insulin resistance, which means that the body can't properly use sugars. Aim for 7-8 hours of sleep a night and your body will thank you! Find out here if you're getting enough sleep.

5. Exercise - In order to lose a single pound of weight, you have to burn a deficit of 500 calories a day for a total of 3,500 calories in a pound of fat. This means that while light exercise may help keep you fit and healthy, it may not be enough to drop the weight. Make sure and schedule workouts at least 5 days a week. Incorporate strength training into your routine 2 non-consecutive days a week. For cardio workouts, challenge yourself with short intense speed intervals - this will really get your metabolism going. For strength training, use an amount of weight that will completely fatigue your muscles within 10-12 repetitions. If you can do 15 reps, it's time to bump up that weight. The key to exercising for weight loss is to ensure you're working hard enough. Check out our beginner's guide to everything fitness.