Another day, another study about the benefits of eating fish—and for good reason. We know from animal studies that when your diet is deficient in omega-3s, the natural rhythms of your pineal gland—the pea-size gland in the center of your brain—are thrown off, leading to alterations in the production of melatonin, your sleep hormone. Animals with an omega-3 deficit don't sleep during their usual rest periods—they're up and spinning in their wheels the same way that humans with insomnia do.

A diet rich in omega-3s, on the other hand, can boost heart health, lower your risk of dementia, and improve your moors. As for weight loss, many omega-3 carriers are rich in protein. And study after study confirms: Protein makes you feel full. You even burn more calories digesting protein than you do when you eat fats or carbs. How to get your dose: If you aren't eating plenty of omega-rich foods—think sardines, salmon, halibut, walnuts, flax seeds, and dark leafy greens—you should be! If you aren't getting enough easily, you can take fish- or flax seed-oil supplement.