Hunger and food cravings are two different things. Hunger is controlled by a biological need for energy in the form of food, whereas cravings are controlled by the brain.
Food cravings are related to many different factors. Areas in the brain responsible for memory and sensing pleasure are partially to blame in food cravings. Research suggests that memory areas may be more influential in reward centers than other centers of our brain. This may explain why sometimes we don’t enjoy the desired food as much as we thought we would and why we sometimes remember a specific food tasting better than it actually does when we do eat it.
Food cravings often arise as a coping mechanism to combat negative emotional feelings, like anxiety and stress. Both carbohydrates and fat are often at the center of cravings and can increase levels of serotonin, a hormone that has calming effects; this is seen in rat studies where rats were put into a high-stress environment. The stressed rats preferred to eat sugar and fat and there was a decreased level in production of stress-related hormones after consuming the sugar and fat. Carbohydrates often get the blame, but fats are just as guilty in cravings. Potato chips, cookies, ice cream, and French fries have both carbohydrates and fat – the combination may be important in reducing stress-related hormones.
There may also be some encoding in our genes as well to crave high-energy (i.e. calorie) foods as a way to prevent starvation during periods of famine and hardship.
Scientists have debunked the theory that we crave specific foods because of a specific deficiency, there’s not much nutrition we can get from mac & cheese!
How hunger works:
When our blood sugar levels are low and we have an empty stomach, the body produces a hormone called Ghrelin. Ghrelin communicates with the hypothalamus in our brain, which then triggers release of neuropeptide Y – the hormone responsible for stimulating appetite.
When we begin to eat, the hormone called leptin is released. Leptin tells our brains that we are satisfied and can stop eating by reducing the amount of neuropeptide Y released. The hypothalamus also monitors our insulin and blood sugar levels.
Pretty cool, huh?!
What do to about cravings:
Balance your blood sugar levels. Our bodies will often crave foods when we are hungry and have low blood sugar levels. If we can manage our levels, we can better focus on things that actually matter. Eat carbohydrate-rich foods in combination with protein and fat for meals, and pair up carb snacks with protein or fat for snacks. Some examples of balanced snacks include apple + peanut butter, an orange + cheese stick, and grapes + nuts or seeds.
Don't make unrealistic restrictions. Strict restrictions can make cravings worse - this depends a lot on environment, relationship with food, overall thoughts about health, and where someone is in their health journey. A study in 2007 found that women who tried to strictly restrict chocolate ended up eating more chocolate than women who ate it when they wanted to.
Eat lots of fruits and veggies. Flooding your body with the micronutrition provided by fruits and veggies may be able to help as well! The recommendation together is about 7-13 servings per day. When you feed your body well, it feels good and craves more of what makes it feel good!
Make sustainable healthy changes. If someone normally has a very unhealthy environment and then makes changes to a healthier lifestyle, there will be some kind of stress involved. Anytime we change things (either intentionally or by force) there is some stress involved - some can be good, some can be bad. If the change is too much, (even if it’s healthy change) it begs for a coping mechanism at some point. Some stress can be good for behavior change if it’s in a healthy amount. Consistency and small, sustainable changes is so important for long-term change.
Go for Team Consistency versus Team Perfection. Sometimes people will go 100% on a diet or lifestyle change and stay consistent for maybe one week, two weeks, maybe even 1 month, then crash when it’s not sustainable any longer. They would have been better off making 90%, 70%, 50%, or even 25% healthier choices over the long-term period.
Find ways to manage stress and anxiety. We know that stress and anxiety play a role in food cravings. If we can limit those, we can be better off in preventing those cravings to begin with.
Sometimes we need sleep. When are bodies are tired, it craves energy which manifests itself into craving carb and fat-rich foods. If you are eating balanced meals and have tried everything else, this may be the culprit. You may just need to get in more quality sleep.
You may hear about Glutamine supplementation to help curb your sweet tooth. Glutamine is an amino acid and is touted for curbing a craving for sweets. Glutamine is conditionally essential, meaning that at certain times, the body will need to get it from an exogenous source (from food or a supplement) versus endogenous (able to be created in the body). Some examples include extreme illnesses and serious injuries, including burns, in order to help with recovery. It’s something used in the hospital setting and assisted living facilities. In generally healthy individuals, the body can use amino acids from whole foods to synthesize enough glutamine. There is not strong evidence that glutamine helps the already-healthy individual decrease sugar cravings. There’s a good amount of anecdotal evidence of people using L-glutamine to help decrease cravings, but this does not count as hard science as this is often biased reporting and a placebo effect. But hey, if you want to try, there doesn’t seem to be a lot of negative side effects…other than emptying your wallet. The placebo effect is sometimes all that’s needed to help!
There is also research to suggest that our gut microflora may also play a role in food cravings. We may be able to better guard against annoying cravings by introducing a probiotic and consuming more foods that support a healthy gut microflora (i.e. lots of fruits and vegetables). It seems that when someone has a healthy gut microflora, they crave less added-sugar foods because healthy microflora reproduce and stay healthy by “eating” healthy foods, including fiber. Healthy microflora survives and thrives with healthy food! While this likely won’t fix it all, it can be another way to manage and promote healthier cravings.
At the end of the day, balancing food cravings in not a one-size-fits-all approach and can require some "self-experiments" to figure out what works best for you. Working with a dietitian can help unlock your food cravings.