Most people take a common set of steps when preparing to lose weight. Pick an activity. Pick a diet. Cut out junk food. Pick a start date. Recruit support. One step, however, is typically missed, and recent research suggests it is as important as anything: Review your sleep habits.

We all know how sleep can affect us. A poor night often results in complaints of low energy, poor work performance, and irritability. We may even recognize that we tend to be less active after a night of poor sleep -- but most of us do not pay much attention to how sleep may affect our eating behavior.

Think carefully -- do you ever crave certain foods after poor sleep? Personally, my sleepless nights are often followed by cravings for "comfort foods," which can be high in fat and carbohydrates. And science confirms it. More and more scientific literature is pointing to a tie between the amount of food we eat, our food choices, and the time of day when we eat -- all factors that could keep the number on the scale from dropping.

In experiments comparing short sleep duration (about five hours a night) to more normal duration (seven to eight hours a night), researchers have found that study participants who are forced to shorten their sleep crave the high fat or carbohydrate laden foods later at night, and they eat more than people who sleep longer.

Weight maintenance is a balance of energies. Simply put, we get energy from the foods we take in, and we expend energy from our activity. We can gain weight when we take in more than we expend. What is interesting about sleep and weight research is that the amount of food short sleepers take in at night far exceeds the amount of excess energy they expend by staying awake. This imbalance between the energy taken in and the energy spent results in an increase in weight, or when undergoing a weight loss program, less success in an attempt to lose weight.

Energy levels for exercise may be limited during days after short sleep, making it hard for us to bring our greatest effort to our workouts. Many exercise programs recommend increasing intake if you feel you cannot keep up with workout demands. The upshot of all of this is that we must find the right balance of intake to maximize our workout regimen and burn as many calories as possible.

These studies show the relation between sleep and weight, but the real world experience is far from that of a sleep laboratory. Epidemiological studies have less control over their participants, but they reflect the real world. It is most compelling when both experimental and epidemiological studies show similar results. This is exactly the case with sleep and weight.

Epidemiological studies have also shown that disturbed sleep leads to increased weight gain. In one large study, those who had excessive sleep time (>9 hrs./night), or short sleep duration (less than six hours per night) gained more than 4 pounds -- more over a six-year period than those who had "normal" sleep duration (seven to eights hours per night). So, there may be a target for the amount of sleep one needs to maximize weight loss.

But, sleep is not just about the number of hours. This relationship also holds for the quality of our sleep. One could be getting seven hours a night and still feel as though the quality of sleep is not up to par. A number of factors can affect sleep quality -- sleep apnea for example, can disrupt sleep hundreds of times throughout the night. These disruptions affect our metabolism and make it harder to lose weight. The prevalence of sleep apnea has increased significantly as obesity rates have increased and there is evidence that up to 7 percent of American men are affected by this disorder.

Successful sleep apnea treatments exist and have shown promise in helping some people lose weight. Many weight loss programs, including the television show The Biggest Loser, screen for sleep apnea and treat it during the course of its weight-loss program. Other sleep disorders (insomnia, restless legs syndrome, periodic limb movement disorder, etc.) also impair sleep quality and should be considered for treatment if symptoms are present.

Now, let's not jump to conclusions. Many people need more than eight hours of sleep and many do fine with less than seven. We should not infer that these people, who are getting the sleep they truly need, should change their sleep in order to lose weight. It may be that, with more research, we can define personal recommendations around sleep duration within a weight loss program. For now, considering the quality of sleep when embarking on a healthy living regimen is a good place to start. Some things to consider are:

Are your sleep and wake times relatively consistent?
• Are you giving yourself enough opportunity to sleep so that you can wake feeling rested?
• Is your environment conducive to undisturbed sleep?
• Do you value sleep enough to change things if needed?
• Do you ever feel rested? If not, do you have signs or symptoms of a sleep disorder?
• Do you change what you eat when you sleep less?
• Do you allow yourself to eat later when you sleep less?

Monitor your sleep as a part of your weight-loss regimen. Examine your own relationships between amount and quality of sleep and food choices, timing, and energy levels. Give yourself the best opportunity to do well in your attempt to lose weight, and recognize that sleep should not be ignored. All in all, consider sleep as a part of healthy living.

Remember, however, that you may need support. The National Sleep Foundation and the American Academy of Sleep Medicine are good places to start to get information and advice. Give weight loss your best effort and sleep well.