Have your healthy intentions ever been felled by the smell of French fries? Or slain by the sight of chocolate?

When you've got a food craving for something specific, it might seem as if your stomach growls are instructing you to drop what you're doing and eat a brownie. Or skip the salad and help yourself to a nice slice of pizza for lunch.

A new study from the University of Pittsburgh suggests that your suspicions about cravings might be right! Your gut might have some persuasive powers when it comes to what you put on your plate.

In the study, the researchers bred mice without any microbes in their guts. Then they gave them gut microbes from different rodent species with distinct foraging strategies. The scientists found that depending on the microbes, the mice voluntarily chose different diets.

Those given herbivore gut microbes selected higher protein-to-carb diets, while those given omnivore or carnivore gut microbes selected lower protein-to-carb diets.

Food cravings, explained: Why you really want those fries

The study authors concluded that the gut microbiome appears to influence food choice. "Our work shows that animals with different compositions of gut microbes choose different kinds of diets," one of the researchers said. However, he called for more research into food cravings. "It could be that what you've eaten the day before is more important than just the microbes you have," he said. "Humans have way more going on that we ignore in our experiment. But it's an interesting idea to think about."

What are food cravings?

You have likely felt it: that overwhelming craving for a snack, be it ice cream, salty foods or other treats. Food cravings are extremely common; more than 90% of the population experience cravings, according to multiple studies.

Cravings are often blamed for diet failures, because they lead to eating between meals and the overeating of high-calorie foods. And because we rarely long for broccoli or kale, cravings usually don't do our overall nutrition any favors, either.

Are food cravings physical or psychological?

Although the study provides evidence that cravings are physical, we all know there is both a physical and psychological component to cravings. Emotional eating and craving chocolate (or craving other high calorie foods) tend to go hand in hand, after all.

Research shows women and men tend to crave different foods, supporting the stereotype that women crave sweet food and men crave savory food. Studies also find that women tend to have more cravings, which suggests a physical, hormonal connection to food cravings.

The hormone connection is not surprising. Eating your favorite food can lead to a release of dopamine and serotonin, two of your "happy hormones." But the environment is to blame, as well. After all, seeing a gorgeous dessert tray at a restaurant can lead to serious sugar cravings, and the smell of barbecue can stop grown men in their tracks.

Other cues to food cravings are more psychological, such as the experience of chronic stress or negative emotions, which can lead to a night on the couch, crying into a pint of ice cream. Even good food thoughts, such as happy memories of family dinners, can make you crave calorie-dense comfort food.

All the food-related ads in our environment play a role in our eating habits, too. Those images can lead to conditioned food responses, such as your mouth watering when you see a burger flipping on the grill on TV, or craving salt when the popcorn bucket dances across the movie screen. Even seeing a restaurant logo can prompt a conditioned response, such as pulling into the drive-through lane for a quick coffee and doughnut instead of going straight to work as you intended.

Food cravings might seem harmless, but research from Tufts University shows addiction-like effects. MRIs completed during the induced cravings showed that the parts of the brain involved in food cravings are identical to those involved in drug addiction. Cravings light up the memory center, which helps reinforce the reward-seeking behavior that causes them. They also stimulate the part of the brain that contributes to the emotional connection between food and cravings.

And because eating good food gives you a flood of pleasure from the release of the hormone dopamine, food cravings follow the reward circuit seen in drug and cigarette addictions. Eventually we might need to consume more of that food to have the same pleasant experience.

Which vitamin deficiency causes food cravings?

Although some claim you can pinpoint your nutrient deficiencies by analyzing your food cravings, there is little evidence to back up this theory. So that craving for chocolate doesn't necessarily mean you are deficient in magnesium.

Also, research points to gender differences in cravings, but studies do not support nutrient deficiency being divided by gender in general.

The best way to determine if you're deficient in a nutrient such as magnesium or a vitamin like B12 is to get a lab test. Don't rely on whether you are feeling salt cravings or sugar cravings to make decisions about your overall nutrition.

Also, be aware that craving non-food items, such as chalk or ice, is associated with an iron deficiency or other health conditions. If you are experiencing non-food cravings, talk to a doctor.

What triggers sudden food cravings?

Food cravings can be caused by a whole host of factors: Are you stressed? Are you getting your period? Are you pregnant? Are you dehydrated? Are you just hungry? These are common causes.

Your late night might be responsible. Studies show a lack of sleep can lead to an increased appetite and feelings of hunger—especially a craving for carbs.

External cues such as the sight, sound and smell of food also trigger cravings. These sights and smells can cause salivation, increased heart rate, and worse, ghrelin release. So maybe you weren't hungry before that pancake commercial, but you are now.

Are food cravings an early sign of pregnancy?

While pregnant women tend to experience cravings (frequently but not always, and generally during first trimester), just having a craving doesn't mean you're pregnant. Men experience cravings, too. And most women experience cravings when they are not pregnant, especially women entering menopause.

That said, if you are a sexually active woman who generally doesn't have strong cravings, and you suddenly experience a change in appetite (or crave pickles), consider taking a pregnancy test.

What does a food craving mean to your health?

Food cravings are a normal part of being human. However, if you are often eating energy-dense or salty snacks and taking in too many calories, cravings could affect your health (and any weight loss plans). If cravings lead to weight gain, food addiction, or blood pressure or cholesterol concerns, you should talk to your doctor about strategies to help curb cravings.

How do you stop food cravings?

If you find that cravings are very difficult to deal with and are interfering with your weight loss goals, there are healthy ways to deal with them.

• Snack on foods such as raw vegetables. This might satisfy your craving for potato chips, and fresh berries can stand in for high-calorie sugary foods.
• Consider adding nutrients such as saffron, lemon verbena and hibiscus, white kidney bean, and spinach extracts, which can help manage your hunger.
• Drink more water. We often mistake thirst for hunger. Try drinking a glass of water (which has zero calories) the next time a craving strikes and see if that satisfies your stomach.
• Try eating foods that keep you full, such as foods high in fiber or high in protein, which are also lower in calories.
• Manage your stress and take steps to maintain normal cortisol levels.
• Consume a varied diet that is rich in nutrients to help satisfy your desire for certain tastes.

References

• Fesler, Katie. "The Craving Brain." TuftsNOW, February 2014, https://now.tufts.edu/2014/02/11/craving-brain
• Hallam, Jessica et al. "Gender-related Differences in Food Cravings and Obesity." Yale J Biol Med.¸ June 2016, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4918881/
• Malik, Saima et al. "Ghrelin modulates brain activity in areas that control appetitive behavior." Cell Metab., May 2008, https://pubmed.ncbi.nlm.nih.gov/18460331/
• Sinha, Rajita et al. "Food craving, cortisol, and ghrelin responses in modeling highly palatable snack intake in the laboratory." Physiol Behav., September 2019, https://pubmed.ncbi.nlm.nih.gov/31145919/
• Smiley, Jeanna D. "Could the gut microbiome be responsible for food cravings?" MedicalNewsToday, April 2022, https://www.medicalnewstoday.com/articles/could-the-gut-microbiome-be-responsible-for-food-cravings
• Sun, Wendy et al. "Regulating Food Craving: From Mechanisms to Interventions." Physiol Behav., April 2020, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7321886/
• Trevelline, Brian K. et al. "Got food cravings? What’s living in your gut may be responsible." Science Daily, April 2022, https://www.sciencedaily.com/releases/2022/04/220420151540.htm
• Trevelline, Brian K. et al. "The gut microbiome influences host diet selection behavior." PNAS, April 2022, https://www.pnas.org/doi/full/10.1073/pnas.2117537119

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