Science of Cravings
What exactly is a craving?
Essentially it is a series of chemical reactions in that body that can cause us to have an amplified desire for a certain substance.
What is the goal of this?
The goal of this is to give you the knowledge to be able to meet “cravings” with more understanding rather than guilt or shame. We want you guys to realize that cravings are completely normal and a response from your body to bring you back in balance. You should never feel guilty because you have a certain craving. How you go about satisfying these cravings can be detrimental, but hopefully this will give you some insight on how you can recognize them and start to address them better.
Overview of our Hunger/Appetite Systems
We have 2 main hormones that are directly involved hunger and satiety. Leptin, which is your satiety hormone, gives you that satisfied feeling after a meal and is released by our adipose tissue (fat). Ghrelin is our hunger hormone typically released when you have not eaten for a while and is actually released largely in our stomach. These both communicate with H.P.A. access (Hypothalamic Pituitary Adrenal/ Thyroid), which regulates energy signals/ hormones in our body and tells us what we need. Essentially, these can play a big role in cravings as a call to fuel our body properly and bring our body back in balance (homeostasis), but our goal is to figure out what is causing that imbalance.
Appetite is a little bit different, even though they can be somewhat correlated. Have you ever finished a large meal, but still had a ‘room’ for a slice of cake or some ice cream? You definitely weren’t hungry, but you still had an ‘appetite’. Our brain (specifically our hypothalamus) is what regulates our appetite (along with a million other things) and receives information from a number of different signals (HPA access). The key thing here is that it can be extremely influenced by your environment (messages that are going on all around you, good or bad) as well as what you put into your body because your hypothalamus is where your endocrine system (hormones) and nervous system mix (how you read the world).
There are also 2 neurotransmitters that play a role in cravings. Dopamine, which is a big reward-based neurotransmitter that drives us to meet that reward. And Serotonin which is a chemical that plays a big role in maintaining mood (feel good hormone) and balance in your body. 80-90% of this chemical is actually produced in your gut, not your brain so your gut environment is crucial with the production of serotonin.
How does this tie into Cravings?
Hunger and cravings are NOT the same thing, cravings are experienced solely in the brain. Hunger tells you that it is time to eat, whereas cravings will hit you with something like “Gimme some chocolate!” A craving is something that you’ve essentially just drilled into your brain. You have created a ‘biochemical feedback loop’ in your brain so your body craves something whenever there is a certain behavior (i.e. eating when you are stressed or eating at night).
What really causes cravings then?!
There are a few different factors that cause cravings. The first one we are going to look at is cravings and diet. Everyone has this desire within us to meet certain macro/micronutrient needs. Have you ever tried going against your innate biology? You are 100% going to lose that battle eventually. Our body wants us to be as healthy as we can be so when you are nutrient deficient, your body might just want a certain kind of nutrient to get you back to homeostasis. “Chronic nutrient deficiency leads to chronic overeating.” I should point out that we want to get these nutrients from real foods not supplements because they are the most bioavailable. There was a study by the International Journal of Obesity on healthy overweight or obese individuals for 8 weeks giving them egg breakfast or a bagel breakfast (while restricting calories). The results showed that the egg breakfast group had “61% greater reduction of BMI, 65% greater weight loss, 34% greater reduction of waist circumference and 16% greater reduction in body fat.” What this is basically saying is that the group that had a breakfast with more “nutrition” (choline, other vitamins & minerals, protein, etc.) was able to feel more satisfied (leptin functioning properly) than the bagel group, which had little to no nutrient density, and possibly lead them to have cravings for food later. Remember how I talked about how cravings hit you with something specific like “chocolate?” Well your body is smart and it knows what is in those specific foods so your body could be craving a specific nutrient that it needs. Cacao used in making chocolate actually has loads of nutrients like magnesium (#1 mineral deficiency in the western world), antioxidants, iron, etc. so that could be a reason why you get hit with that craving. Another example of this that people often see is when you have a craving for salty foods, your body might just be dehydrated and the minerals found in salt allows you to hold onto more water.
Sugar is a little more complex because they are SO much more addictive. Foods with a lot of added sugar is not natural to our biology so eating these foods can actually damage our leptin sensitivity and stimulate our appetite (going back to paragraph 3). A good way to frame this is when you eat a lot of donuts or gummy bears you never feel satisfied even though it is a lot of calories because these types of foods lack nutrients (fiber, vitamins, minerals, etc.) that we need and our body continually tells us that we need more because it’s craving the proper nutrients. BUT it tells you to eat more of that specific thing because it knows it is a quick energy source and it doesn’t know exactly when it will get its next fuel supply. That being said food should be enjoyed and we should never deprive ourselves of this! However, we can start to think about ELEVATNG the quality of these foods by choosing brands with quality ingredients or by making things like oatmeal cookies that are sweetened some raw, local honey or my favorite…sweet potato brownies. Then you get a whole bunch of nutrients, it tastes amazing and makes this lifestyle sustainable.
Sleep can actually be one of the biggest triggers of cravings as well. A sleep study of over 1000 people showed that short sleep reduced leptin and increased ghrelin. When your sleep deprived your hormones are all out of whack (cortisol is elevated) and stimulates the activity of the survival part of your brain (amygdala) along with decreasing the area that is involved with willpower (prefrontal cortex). Research has actually shown that a sleep debt of 24hrs reduces can cause a 6% reduction of glucose reaching your brain so then your body will crave that quick source of sugar it knows it will get from candy, donuts, etc. Improving our sleep quality is crucial here and eating high quality, real food can help with that tremendously.
Emotional eating is definitely something most people can relate to. Stress is often correlated with an increase in cortisol/adrenaline production throughout our body. When those two things go up, it eventually causes a drop in blood sugar, which immediately signals our body to get back into balance and increase our blood sugar… cue cravings especially for carbs. Why is that?! Well carbs release a large amount of serotonin when consumed which we know now is that ‘feel good’ hormone so naturally we are going to want those even more when stressed. We can combat this by using a variety of different stress management techniques like working out or practicing being more mindful/meditation to help us respond better when we are stressed. Now that we are able to start to understand where these cravings come from, we can address them better and elevate our food choices when we do notice that drop in blood sugar!
There are a couple more ways we can address these cravings; one way is through exercise. Now I am not saying “workout so you can eat” at all, but a lot of the time we think that by working out we will just be absolutely ravenous afterwards, but that actually is not the case really… of course we want to make sure we are refueling properly afterwards, but working out has actually been shown to suppress ghrelin and put our hunger hormones back in balance. That is why whenever you work out hard you have a decreased desire to eat lower quality foods afterwards. Exercise also increases dopamine in the brain so when we might just want that dopamine hit from food, we can get that from working out. Throw that in with eating nutrient dense foods and this will really help bring your hunger/ satiety hormones back to normal levels. This goes along with still enjoying yourself because we are all about sustainability here but elevating the quality of your treats/ food on a more frequent basis is KEY. Furthermore, increasing our intake of fat from quality sources (avocados, nuts, etc.) leaves us feeling more satisfied for longer and they also contain a lot of essential fatty acids which could be a nutrient deficiency leading to cravings. Focusing on nutrient dense foods, exercising, having meaningful relationships, finding hobbies you enjoy, etc. have all been shown to give us that hit of dopamine we might be craving and they also give us that overall satisfaction in life that we all are striving for.
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