There are two main theories behind why cravings (a heightened desire for a specific food) occur.
The first one is that we develop cravings based on a specific nutrient need of the body. That somehow our body senses that we're not getting enough of a particular nutrient and therefore makes our brain seek foods rich in it. You know those infographics where it's like "if you crave chocolate it means you're low in magnesium...".
This is a popular theory, and I think it's primarily due to the appeal of it being intuitive. People like the idea that the body has this internal sensor that notices these things and secretly makes us crave foods rich in it.
If this theory were to hold true, then we would expect to see cravings increase over time if the nutrient need wasn't met (ie. we didn't eat the craved food) or during periods when nutrient intake is likely reduced, such as dieting.
Well, it just so happens that a recent meta-analysis (where researchers take a number of individual studies and combine them to analyse the data as a whole) can provide us with some clues. Kahathuduwa (don't ask me to pronounce it) and colleagues integrated the results of eight studies that examined how aggressive dieting affects food cravings in people with obesity. The studies included had to run for a minimum of 3 months. Contrary to what we may have expected, cravings dropped significantly over the course of a diet! In particular for sweet food and fast food.
What does this mean?
Well, for starters, it directly opposes theory number one. We would expect given the length of the diet and the size of the deficit that, if anything, cravings would increase during this time.
So if a nutrient deficiency doesn't cause cravings, then what does?
Remember at school when they taught you about Pavlovian conditioning? When Ivan Pavlov discovered that a group of dogs learnt to associate a neutral stimulus (a bell ringing) with a reward (food).
No?
Well trust me on this and keep reading, it will all make sense soon.
Ivan discovered what we now know as a 'Pavlovian conditioning' and set the stage for theory number 2, that cravings are a conditioned response.
To understand this concept we need to consider our evolutionary past.
Unlike us, our ancestors didn't give a shit about how many followers they had on Insta. Instead, they were all about the three "S's". Survival, Sex and Sabretooths!
Our Ancestors main concerns...
Okay, maybe not that last one but survival and reproduction were their primary goals. To achieve these goals, they needed food, water and safety. They weren't so worried about getting enough magnesium or eating enough anthocyanins from purple veg and fruits. They required the OG; calories.
But how did they know what foods provided the most calories and would, therefore, increase their chances of reaching their goals?
Our brain has a well-greased system that determines our motivation for particular foods. Unfortunately, this system hasn't been updated and was developed in times when calorie dense foods were scarce. Essentially, the opposite of our current environment. This system ensured that we didn't waste precious energy hunting down the caveman equivalent of baby spinach, which while nutritious, isn't worth much for survival or reproduction.
The brain LEARNS to reinforce foods which signal calorie density and MOTIVATES us to seek these in the future. Smart right? It learns this through the neurotransmitter DOPAMINE. Every time our ancestors accomplished a goal like eating tender mammoth belly (I hear it's like pork belly); DOPAMINE would be released to REINFORCE that "successful" behaviour.
Dopamine teaches the brain what foods are more valuable from a survival sense and sets our subconsious motivation levels based on this.
Research unquestionably illustrates that the more calorically dense food is, the more REINFORCING it is to our brain. Taking this a step further, the brain learns to associate specific cues/triggers such as flavours, smells, textures, appearances, surroundings, moods etc. to these rewarding, calorie dense foods.
So just like how the ringing of a bell caused Pavlov's dogs to salivate, TV ads of burgers, the smell of pizza or the sight of the dessert menu at a restaurant can cause us to CRAVE these foods.
Essentially, cravings are strongly conditioned responses forged by a lifetime of living in an environment rich in calorie dense foods.
And while the above examples are obvious, other craving cues may not be. Feelings (stress, sadness, boredom etc.), places and other environmental cues can subconsciously trigger cravings for foods.
So if cravings are a response to subconscious environmental, social and emotional cues, what can we do to reduce them?
1. Reduce craving cues.
Similar to other addictive-like behaviours, reducing the amount of exposure we have to cues is a logical way to reduce cravings. Much like a someone trying to quit smoking wouldn't have cigarettes lying around the house, limiting the amount of delicious crave-worthy foods at home and work is a smart move.
2. Give it time.
Good news everybody (*Professor Farnsworth voice).
It appears that while conditioned responses can strengthen when continually reinforced (everytime you satisfy your craving, it enhances it a little), abstaining from cravings works oppositely! Studies illustrate if cravings aren't reinforced by indulging, that they eventually fade because they're not being rewarded.
Reinforcement of cravings (top) versus the extinction of cravings (bottom).
3. Focus on minimally refined foods.
Studies illustrate that humans tend to crave foods that contain multiple innate preferences such as sweet & fatty or salty & fatty. The reason being is that these food traits overload the reward system of the brain, overriding our natural satiety systems and creating strong cravings.
On the other hand, we know that minimally refined, whole foods show a much smaller response in the reward system of the brain, helping us to notice hunger signals and not feel like we need our Ben & Jerry's hit.
4. Don't eliminate the foods you love.
Interestingly, the Kahathuduwa et al. study also noticed a trend that severe restriction/elimination of a macronutrient (i.e. a low-fat or low-carb diet) led to a relative increase in self-reported craving compared to diets that didn't restrict specific nutrients. While IMO this is highly dependent on the individual, this does fit in with the 'forbidden fruit' theory. That upon telling someone they can't eat a particular food, it naturally increases the amount of time they focus on that food. Hence, we would see increased cravings from following a diet where we set RIGID elimination type rules.
Rather than focusing on what foods you can't have, focus on the foods you should be eating eat more. Additionally, if you're going to eat food you crave, it may help to consume it post-meal when you're not hungry. There is some data to suggest that consuming chocolate with a meal rather than as a way to satisfy hunger resulted in fewer cravings.