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The Science Behind Food Cravings, from Genes to Deficiencies
Food cravings are complicated things – and concepts that most people struggle to fully understand. One minute you’re completely focused on finishing a memo at work, and the next you can’t quite focus beyond an all-encompassing need for something greasy, salty, or sweet. Cravings can be difficult to understand, hard to predict, and can leave some people feeling completely out of control of their own desires. Fortunately, scientists and recent studies have begun to shed light on how everything from the environment, our emotions, and even our genetics can play a role in determining which foods we’re suddenly compelled to devour.
It’s hard to deny that food cravings, including people’s likes and dislikes, are impacted by a number of different and crucial variables, and many of those factors are still unknown. However, researchers and nutritionists are beginning to discover much more about what goes on in the brain and body when we are hit by sudden cravings, and why some people are genetically hard-wired to crave certain foods more than others.
Cravings Are in Your DNA
Today, obesity is recognized as one of the deadliest health conditions on earth. In fact, according to a RAND study in 2002, it leads to far more problems with your health than other issues like poverty, drinking, or smoking. While it’s clear that things like too little exercise and too much food can propel issues of obesity forward, researchers have long believed that certain biological factors might also have a part to play at putting specific people at increased risk of weight-related problems. The suspicion itself has even prompted a search for an elusive “fat gene”.
The specific genes that come together to make you, you, could be what changes your need for something healthy, like fruit or vegetables, into a craving to high-fat, or high-carb food items. For instance, one recent study that was presented at the European Society of Human Genetics found that people’s preferences for foods like bacon, coffee, blue cheese, dark chocolate, and broccoli can all be linked to certain genes. In fact, even the amount of sugar or salt a person eats could be linked to genetics – according to research presented at the conference.
Simply put, there are genes for almost everything, from parts of your DNA that make you more predisposition to excessive snacking, to parts that prompt sugar addiction, affect satiety and hunger, and even ensure you’re more likely to reach for a burger than a carrot stick.
The Genetics Behind Junk Food Cravings
One particularly interesting study into the connection between genetics and cravings, was presented at the Obesity Society Annual meeting, and indicated that there are two specific genetic variants that influence whether we’re more likely to choose low, or high-calorie foods. The study was conducted by researchers from the Imperial College in London, and it involved 45 white European adults between the ages of 19, and 45.
The volunteers of the study were asked to look at photographs of low and high-calorie foods, then rate how appealing they thought they were, while the researchers used a portable MRI machine to examine activity in their brains. Results found that volunteers with a variant of the FTO gene – a gene frequently associated with obesity, rated the high-calorie foods are more appealing, with increased activity in their orbitofrontal cortex (the part of the brain where reward values for taste are stored).
These findings are pretty exciting for scientists today, as they suggest that there is some true genetic influence that might prompt some people to be more likely to suffer from obesity than others. In other words, certain people simply experience higher, more significant cravings when presented with foods that are high in sugar and calories. A study into this research could even help to improve the future opportunities present for developing individualized approaches to obesity treatments, such as using hormones that target the dopamine cells in the brain to alter cravings for high-calorie foods.
The Science Behind Snacking
We’ve already established that genes have a role to play in determining which kinds of food you crave, but how about how much of that food you eat? Your genetics are also important in determining your appetite, and how much you can get away with eating, as well as how good certain foods tastes, how much food it takes for you to feel satisfied, and how long you can stay full for. In other words, genes are involved in every step of wanting, choosing, and eating foods.
Of course, genes aren’t the whole story behind obesity and other weight related issues. Lifestyle factors such as how much you exercise, and whether you choose to give into your cravings play a role too. But it’s safe to say that your DNA could impact everything from how much you snack, to what you snack on. For instance, a recent study into mice found that dysfunctional eating patterns can be caused by the irregular on and off switching of genes within the brain that “expect” food at certain hours in the day.
What’s more, the FTO gene – one of the genes considered in the London case addressed above, has also been found to affect the levels of the hormone for hunger known as “ghrelin” in the body. People who have an altered, or mutated FTO gene typically have higher levels of ghrelin in their blood, which make them feel hungrier after eating a meal, and could help to explain why they are more commonly driven towards high-calorie foods. Dr. Rachel Batterham, from the University College in London, commented that the study showed that people with two copies of the FTO variant were biologically more compelled to eat more.
There are Even Genes for Sugar Addiction and Sweet Tooth Cravings
Even your typical sugar cravings could come from something far deeper than a standard “sweet tooth”. Some research has shown that certain people are genetically more prone to forms of food and sugar addiction than others. Part of the reason for this is that some people are more predisposed to seek out pleasure than others. For instance, in our brain, there is a small receptor known as the D2 dopamine receptor, (drd2). This party of the brain must be activated at all times for us to feel pleasure, and it can be activated by the presence of an amino acid known as dopamine. Stimulating addictions and sugar all prompt the release of increased amounts of dopamine in the short term.
The problem is, those who suffer from sugar addictions, compulsive eating patterns, and even issues of obesity often have DRD2 systems that are in need of much larger portions of stimulation in order for the same amount of pleasure to be felt. In other words, those who suffer from sugar addiction don’t have as many D2 dopamine receptors, and therefore consume excess amounts of sugar in an effort to find the additional stimulation required for turning those receptors on. This is why in studies with functional MRIs of teenagers (both obese and lean), found that teenagers whose brains did not light up as much in the rewards center were more likely to gain weight later in life.
Other Things that Impact Food Cravings
As important as science has shown genetics to be when it comes to understanding food cravings, it’s worth noting that there’s more than just your DNA playing a role in your sudden need for a particular unhealthy snack. Three of the most common factors that impact cravings are:
In some cases, people choose to seek out certain textures or foods because their body is already suffering from a state of imbalance. For instance, when our blood sugar levels begin to drop – either because we haven’t eaten for a while, or because we are more genetically predisposed to have low blood sugar levels – we often crave sugary foods to raise them back up. Similarly, endurance athletes who spend hours training every day and lose water through sweat are more likely to crave salty foods that will help them to make up for lost sodium.
Many people find that they are more drawn towards unhealthy or “comfort” foods when they are overworked, anxious, or feeling seriously stressed. Part of the reason is that you crave high-fat, high sugar, or high-calorie foods when stressed is that your taste buds are actually designed to make them taste better. According to a recent study into animals, the taste cells on the tongue contain receptors for glucocorticoid hormones, which activate during stress periods, causing us to taste bitter, sweet, and umami flavors differently.
Finally, hormones have a huge role to play in the things we crave. For instance, women find that their levels of estrogen begin to fall during the third and fourth weeks of their menstrual cycle – the same time when levels of the stress hormone “cortisol” begin to rise, and levels of serotonin diminish. This often leaves many people feeling cranky and in need of something high-calorie or unhealthy.