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The question: I'm worried my insomnia is making me gain weight. Could this be true? Do certain foods make it easier to sleep well?

The answer: There is evidence that sleep loss is linked to weight gain, in particular abdominal weight gain. Too little sleep has been shown to slow the body's resting metabolism – the number of calories burned at rest – and increase hormones that stimulate appetite and eating. Sleep deprivation may also lead to higher blood levels of cortisol, a stress hormone. Prolonged elevated cortisol levels are thought to contribute to fat deposition around the abdomen.

Even so, this doesn't mean that your insomnia is the cause of a recent weight gain. Weight gain is dependent on many factors including number of calories consumed, types of foods eaten, timing of food intake and amount of exercise. Reflect on your current diet and exercise habits. Do you notice recent changes that could be driving your weight gain?

When it comes to sleep, altering your diet may help. Eating the right foods in the evening and knowing which ones to avoid can help you fall asleep sooner and sleep more soundly.

First, assess your caffeine intake. While one or two cups of coffee can boost mental alertness, drinking more can overstimulate your central nervous system and cause insomnia. Drinking even as few as two small cups of caffeinated coffee can affect sleep quality. That's because caffeine blocks the action of adenosine, a sleep-inducing brain chemical.

Eliminate caffeine-containing beverages eight hours before bedtime. Aim to consume no more than 200 milligrams of caffeine per day, or preferably none. One eight-ounce cup of regular coffee has 80 to 175 mg of caffeine; the same amount of black tea has 45 mg.

Drinking alcohol can also disrupt sleep, causing you to wake up in the middle of the night. Alcohol also dehydrates you, which can worsen your fatigue the next day. Avoid alcohol for a few weeks to see if your sleep improves. If you do drink, limit your intake to one alcoholic beverage per day (e.g. 5 oz of wine, 1.5 oz of spirits, 12 oz of beer).

If you have sleep apnea, a condition that makes it difficult to stay asleep, drinking alcohol can make your throat muscles relax more than normal, increasing the chance that airways get blocked. Sleep apnea occurs when the upper airway gets completely or partially blocked during sleep and breathing momentarily stops. These breathing pauses, or apneas, can last up to 30 seconds and can happen many times throughout the night. The brain senses this breathing difficulty and briefly rouses you from sleep to reopen your airway.

Eating your evening meal late can also affect your ability to sleep well. Eat dinner at least three hours before bedtime to prevent digestive upset that can keep you awake. And keep your meal light. The more fat you eat at dinner, the more likely you are to experience sleep disruptions.

Consider making your evening meal carbohydrate-based rather than protein heavy. Preliminary data from mice reported earlier this year found that the rise in insulin triggered by carbohydrates helped to reset the body's circadian clock, promoting sleep. (Our circadian or biological clock in the brain regulates sleep and wakefulness, often by environmental clues.)

For dinner, try a stir-fry with brown rice, vegetarian chili, entrée salad with chickpeas and quinoa or pasta with marinara sauce. Shift the majority of your protein (e.g. lean meat, poultry, fish, egg whites, soy) to breakfast and lunch. Protein-rich foods help the brain make dopamine, a chemical that makes us feel alert.

Finally, avoid drinking fluids two hours before bedtime to reduce the likelihood of needing to get up in the night to go to the bathroom.

If your sleep problems persist despite making these dietary changes, consult your doctor to determine the underlying cause.

Leslie Beck, a registered dietitian, is based at the Medisys clinic in Toronto. She is a regular contributor to CTV News Channel.