In the movie "Heartburn," Meryl Streep (Rachel) and Jack Nicholson (Mark) eat spaghetti carbonara in bed — and they're headed for a breakup.

In "Bridget Jones's Diary," Renee Zellweger (Bridget) snuggles under the covers for a rendezvous with excessive amounts of comfort food.

Neither of those is a formula for a good night's sleep. But there are foods that can improve your sleep. Just don't eat them in bed, or too close to bedtime:

• Soy. A 2015 study in published in Nutritional Journal found that eating two servings a day of soy, which is rich in isoflavones, increased sleep times and quality, and was especially helpful for postmenopausal women.

• Fiber-rich foods. A study from the Obesity Research Center and Institute of Human Nutrition at Columbia University revealed that the more fiber you eat, the better quality your sleep — in part because it increases the amount of slow-wave sleep you get. (Slow-wave is the deepest phase of non-rapid eye movement sleep.) The reason may be that fiber stops blood sugar swings. A study in the journal PlosOne found that people with higher glucose levels had poorer sleep. And another study found that 62% of people with prediabetes have poor sleep.

• Fish. Salmon, especially (but also canned tuna and halibut), boosts levels of vitamin B6, which is essential for producing the sleep hormone melatonin.

Other sleep-friendly foods include tart cherry juice (it raises the availability of sleep-inducing tryptophan and quells inflammation), B6-rich bananas, and green leafy vegetables such as kale, which contain calcium and magnesium (a deficiency of either makes it harder to sleep).