Everyone knows that what you eat can have an impact on your waistline and your health, but your food choices can also have an impact on your energy and concentration at work.

I recently worked with an entrepreneur named Ned who made it a habit to skip breakfast. In fact, he often skipped lunch and managed to get through the day on coffee and random snacks, such as cookies and candy, that his employees kept around the office. This was a habit he both fell into and latched on to as a means to keep his weight down and to compensate for the huge amount of food he was eating in the evening after work. The problem was, it wasn’t working. In addition to being 20 pounds overweight, Ned was extremely stressed out and had insomnia. 

A lot of entrepreneurs I know are like Ned: They're stressed out and sleepless, and they don't have time to worry about what they eat. Though it’s always better to embrace healthful eating habits, such as having three square meals, this is often an unrealistic goal for busy entrepreneurs. But there are a few key nutritional habits that can boost your energy levels, keep your appetite and cravings under control, and help you feel more focused: 

1. Eat breakfast. Studies show that productivity drops a whopping 50 percent to 75 percent when you skip breakfast. But what you eat is also important. Starting your day with a balanced breakfast that includes protein will help keep you energized for about five to six hours. I recommend egg-white omelet with veggies. Muffins? Not so great. You’ll likely be crashing within an hour or two.

2. Step away from the sugar. The entry drug of stress management, sugar is cheap, tasty, and absolutely addicting. When you experience stress, a dynamic is created in your brain in which dopamine is high and serotonin levels are low, creating an imbalance that feels uncomfortable. To compensate, your brain makes you crave sugary foods for a quick burst of serotonin. That may sound great, but the serotonin levels quickly come crashing down. Eventually, your stress levels and mood can become erratic and hard to rein in, making it difficult to focus. Stock your work fridge with healthful snacks such as apples and organic peanut butter (or better yet, almond butter) or hummus and carrot sticks. The carbs from the apple or carrots will boost serotonin levels and provide quick fuel, while the protein and quality fats in peanut butter or hummus will provide long-lasting energy.

3. Don't drink coffee on an empty stomach. A lot of entrepreneurs I work with use caffeine as their main fuel source. Focused on the next task at hand, they forget to eat and instead drink coffee all day to sustain their energy levels. You don’t have to be a nutritionist to know this is not good for you. The caffeine in coffee can deplete serotonin levels for up to eight hours. As a result, this will increase your stress as well as increase your sugar cravings, which, if indulged, will lead to more brain fog. If you're going to have coffee, first fuel up on food. It buffers the absorption of coffee, mitigating its effects.

These three simple shifts in your diet can make a big difference. Two weeks after making these changes, Ned was eating less at night and sleeping better. He still had a ways to go in changing some of his other habits to shed that 20 pounds, but his clothes were starting to fit a little better. What intrigued Ned most was that he had more energy throughout the day, was managing his stress better, and was working more efficiently. That alone, he said, was worth the effort.