Despite the cold weather, winter can be a difficult time to keep your cool. You don't have to have full blown Seasonal Affective Disorder to feel out of sorts during this time of the year. Running a successful business can be challenging enough, but many entrepreneurs say they feel even more stressed during the shorter days of winter. What's worse, you may find yourself seeking comfort in eating bad foods, drinking too much alcohol, or zoning out in front of the TV--activities that may actually be adding to your stress.

But there are some things you can do to improve your mood until the warmer days of spring arrive. Here are nine habits that will help you feel more balanced, calm, and focused, especially during the cold winter months.

1. Reduce or eliminate sugar. Studies have repeatedly shown that if you eat too much sugar and junk food, you are far more likely to suffer from anxiety and depression. Sugar rewires your brain, skewing serotonin levels, which are necessary for a balanced mood. How much sugar is too much? If you find that you are in the habit of reaching for cookies or candy every afternoon, and then nipping into the ice cream after dinner, it is these indulgences that are probably contributing to your stress levels, sluggishness, and irritability. Instead, snack on whole foods: fruit, nuts, or hummus and carrots.

2. Cut back on caffeine. Every cup of coffee can deplete your serotonin for up to 10 hours. That means that if you drink coffee throughout the day and have your last cup in the afternoon, you are essentially spending the day at a serotonin deficiency that will last well into the evening. This will not only make you feel more irritable and anxious, but it will probably get in the way of a solid night of sleep, another essential element of stabilizing your mood. Try to cut off coffee by noon and switch to green tea instead. Green tea has a fraction of the caffeine in coffee and has heart-healthy properties. It can also help to burn stored fat.

3. Eat more root vegetables. Snack on carrots, include sweet potatoes in your meals, or have a carrot soup or a beet salad. Root vegetables are great foods to include in your diet to help improve your mood. They are a great way to boost serotonin levels, and they are subtly sweet, helping to offset more overt sugar cravings that can send your brain reeling. Include a serving of root veggies in your diet daily.

4. Eat foods rich in omega-3 essential fats. The essential fatty acids in salmon, walnuts, and flax are great foods to include in your diet to boost serotonin production. They also act as a sort of emollient to an anxious brain. Have two servings of wild Alaskan salmon a week, a handful of walnuts a day, and one tablespoonful of flax oil daily (which can easily be used in salad dressing), and watch your anxiety dissipate. Meanwhile, your mood, focus, and concentration will improve.

5. Get more rest. The impacts of anxiety and depression go beyond a bad mood. They affect your food choices and your sleep habits. As you make improvements to your diet, work on getting quality sleep. Restful sleep is essential for the production of serotonin. Broken or insufficient sleep will keep you from producing adequate amounts of this essential neurotransmitter, which will then fuel poor food choices and keep you in a cycle of anxiety. Shoot for seven hours a night.

6. Eat breakfast. Skipping breakfast will have a detrimental effect on your blood sugar, starving your brain and leading to poor food choices later in the day. This is particularly true for busy entrepreneurs. Every time you multitask or make decisions, you are plowing through fuel that your brain needs to stay in top form. If you skip breakfast, you are essentially starving your brain for as many as 12 hours! This is going to lead to a lack of focus and concentration, which will in turn lead to difficulties making decisions. Great breakfast options include vegetable omelets or oatmeal with nuts and fruit.

7. Exercise. It is well documented that exercise is essential for a balanced and happy mood. In fact, studies repeatedly show that exercise is a better way to manage mood than taking antidepressants. Plus, studies have shown that working out before getting to the office will help increase your productivity as much as 40 percent. Not bad for a habit that will also help keep your weight and health in check.

8. Take sunshine breaks. The lack of sunlight during the winter months is part of the reason you may be suffering from the blues. Light is essential for the production of serotonin. One great way to boost levels is to get outside for a 10-minute break midday. This will not only help expose you to light; it also may give you a much-needed break in the middle of a hectic day.

9. Plan ahead. It's not easy to make changes to your diet or your life, particularly if you are in a negative frame of mind. One way to make it easier is to plan ahead. Spend five minutes before you go to sleep mapping out the following day. Being mindful of your schedule, write down what you are going to eat for your meals that includes some of the suggestions above. Also write down your intentions for exercise and where in the course of your day you can take a five-minute break to get outdoors and get some sun. This act will help program your brain for success, making the follow-through much easier to navigate.