Q: Do food cravings mean that I am deficient in particular nutrients?

A: If you're dehydrated, feeling thirsty is your body's way of urging you to drink water. If you're tired, feeling sleepy is your body's way of urging you to sleep. Our lives are full of different situations where our bodies have a physical need, which is translated into an urge or compulsion to complete an action that fulfills that need.

But do these mechanisms translate to food cravings and nutrient deficiencies? Not really. While your body can coax you into drinking H2O when dehydrated, it can't urge you to eat more almonds when you need magnesium or a burger if you need more iron.

One reason has to do with our always-changing food supplies. Water hasn't changed since the beginning of time, but our sources of magnesium (think almonds growing on a tree versus in a container in the grocery store) have varied greatly in appearance, taste, and texture over time. And your "lizard brain" (the most primal part of your brain) can't keep up with these changes.

The other more important reason concerns the complexity of signals that drive food cravings or just plain hunger, which can be difficult to tease apart. There are two different types of hunger: physiological and reward-driven. Physiological hunger occurs because your body actually needs calories to maintain itself, while reward-driven hunger occurs for less physical reasons, such as when you feel hungry after seeing some delicious-looking food on TV, smelling an amazing pizza while walking down the street, or when you're really stressed. In fact, stress is the major effector of reward-driven hunger. A 2013 survey from the American Psychological Association found that 84 percent of adults think that their stress levels have increased in the past year, while 88 percent of women (who report higher levels of stress than men to begin with) recognize that stress has a very strong impact on their health-and they're right.

In the end, there is no research to support that our body can urge us to eat certain foods to correct nutritional deficiencies. The presence of strong and prevalent factors like stress that stimulate reward-driven eating would blur or mask any subtle signals that your body might be sending you regarding eating foods to eradicate nutrient deficiencies.