Genetics and Overeating

Jim Greenblatt
Written by Dr. James Greenblatt for ExpertBeacon
August 2014

Many who struggle with overeating believe they are victims of fate.

“It’s in my genes. My mother, my sister, and my grandmother all struggle with appetite and weight problems. I don’t have a chance.”

Genes are the body’s blueprints, providing detailed instructions that create both body and mind. They determine the form and function of each cell in the body, making you who you are. They are passed on from one generation to the next, but in each new birth they combine in a unique way.

Thanks to individual genetic makeup, each person is anatomically and biochemically unique, with his or her own way of responding to the environment. This uniqueness frames the way each of us perceives and interacts with the world. For instance, when a family sits down to enjoy dinner, each member tastes a different dinner, because of the unique distribution of taste receptors in the tongue.

Taste receptors can have a big impact on overeating, bingeing or not eating enough. A study funded by the National Institute on Deafness and Other Communication Disorders has shown that small variations in our genetic code can raise or lower our sensitivity to sweet tastes.

This can also explain why some people are especially vulnerable to addiction to sweets. Taste receptors are overloaded with different flavors during each meal and, if your diet is unhealthy, they adapt to those foods, making spinach and kale taste unappealing.

The differences in how we perceive taste are due to genetics. Those with a sense of taste far more intense than that of the general population are called “supertasters.” Supertasters have an aversion to bitter tastes, and studies show that they have a heightened affinity for salty foods, which mask bitterness.

Undoubtedly, there is a relationship between genetics and a predisposition for food addiction. A survey of Overeaters Anonymous members conducted in the early 1990s found that a high percentage of overeaters or food addicts had at least one blood relative addicted to food or alcohol.

But this and other research raises the age-old question of nature versus nurture. Do these striking correlations run in families because the trait of susceptibility to addiction is passed on genetically? Or is it transmitted in habits and attitudes through patterns of parenting?


Do recognize that genes play a role in overeating
Scientific research has demonstrated that differences in DNA predispose individuals to dependence on alcohol. Now science has linked genes with food addiction as well. Recently, researchers at the UCLA College of Medicine tested a sample of overweight subjects who exhibited a pattern of bingeing on carbohydrates. They found that these subjects had the same genetic aberration that had been established as a genetic marker for chemical dependency on alcohol.

Do plan for genetic testing
Genetic testing has slowly been incorporated into many psychiatric practices. Genetic research is a useful tool, and almost any physician can order a genetic test for a patient. These simple tests, often administered with a saliva collection, can inform clinicians of the most appropriate and effective treatment for the patient, based on his or her unique genetic profile, by analyzing an individual’s genetic and biological markers.

The results reveal how a patient may respond to different psychiatric treatments, and can predict weight gain and appetite disturbances associated with psychiatric medications.

One example of a biological marker of growing interest in many fields of medicine is the methylenetetrahydrofolate reductase (MTHFR) gene. The MTHFR gene is responsible for important biochemical reactions, including conversion of folic acid into methyltetrahydrofolate, or MTHR. This nutrient is involved in mood regulation, as well as appetite control, and those with a polymorphism in this gene will be at a higher risk for mood-related disorders and appetite disturbances.

Another biological marker analyzed is the 5-hydroxytryptamine 2C (5-HT2C) receptor. It is one of the three receptor subtypes of the 5-HTC receptor family and is often targeted by antipsychotic drugs to treat psychotic disorders, such as schizophrenia and depression. It also has been implicated in the control of appetite and subsequent weight maintenance.

Do learn to eat healthy
Our DNA blueprint is only partially fixed. Some parts of it are unalterable—for example, the size of our feet—but many parts are more like suggestions or possibilities than orders. These parts are highly malleable and quite responsive to the environment, to our emotions and to what we eat.

Eating healthy food, such as fruits and vegetables, can have a positive impact on how your genes express themselves, while eating foods that are high in sugar, monosodium glutamate and other ingredients that promote food addiction can have a negative impact.

Do take nutritional supplements
Each of us has a unique biochemistry. By assessing our biochemistry and identifying any deficiencies, we can determine what needs to be done to restore stability. Nutritional supplements, such as amino acid supplements, can enable us to control our cravings and overcome food addiction.

Do make other lifestyle changes
Unfortunately, we have not yet been able to identify a single epigenomic change that leads to disordered eating, and we cannot zero in on a medicine, diet or other approach that will reverse that change.

What we can do is to set the stage for a helpful rather than a harmful epigenome by examining genetic markers like MTHFR, consuming a nutritious diet, reducing stress and otherwise giving the body the tools it needs to build good health. At the same time, we can avoid dangerous habits and behavior that might set up a deleterious change in the epigenome – a change that may be passed on to the next generation and beyond.


Do not blame yourself
You may have failed to lose weight in the past because you—with the help of the medical profession and the food environment of our culture—have misplaced the blame for your disordered eating. You may have interpreted your overeating as the result of a weak will or bad character. But the problem you struggle with is not a moral or a character weakness; it is a biochemical one.

Recognizing that cravings for food come from deep within our biochemistry and outside our conscious control should lead us to see disordered eating through a different lens. And just as we have misdiagnosed the problem of binge eating and overeating in the past, until now we have missed finding effective, permanent solutions.

Once you identify genetic, emotional, and nutritional factors that may lead you to overeat, you can shift the blame for overeating from your character to your biochemistry, where it rightly belongs. From this foundation you can treat disordered eating patterns, attacking problems at their source rather than simply—and temporarily—eradicating symptoms.

Do not use your genes as an excuse
Genetics is not destiny. You may have inherited genes that can predispose you to become addicted to food, but those genes are not destined to control your life. That’s because there is a difference between the presence of genes and their expression. In other words, just having certain genes doesn’t mean that those genes will express themselves.

Epigenetics is the study of how people’s environments and experiences affect the function of genes. Genes are not just proteins that manufacture a product in a uniform way. They carry chemical attachments that act on the DNA to regulate the timing and amount of the protein without changing its basic composition. These add-ons, or epigenetic markers, evolve as an animal or person adapts to its environment.

Do not continue dangerous habits
Reversing the long-held theory that genes are an unalterable prescription that programs not only the color of our eyes but also the diseases we will develop, epigenetics shows that the environment—including our own attitudes, beliefs, life experiences, and behaviors, as well as the time and conditions in which we live—has a great influence over the expression of the genes we were born with.

Dangerous habits, such as over-consumption of junk food and fast food, can not only increase your probability of food addiction, but affect the propensity of your unborn children to become overweight and have food addictions.

Do not try to address overeating without help
Trying to solve your overeating problem on your own can be frustrating and is bound to lead to failure. Binge eating disorder is both complex and pervasive, and is impossible to resolve with logic or willpower alone. An effective treatment plan incorporates advanced medical and psychological approaches that are specifically tailored to one’s unique biochemistry and experiences. An experienced team will be needed to develop a plan that works for you.

You should work with a healthcare provider familiar with biochemical individuality to create an individualized supplement program based on the results of your metabolic tests. Don’t try to figure it out yourself, as overloading on supplements or taking those you don’t need can be expensive and frustrating, as well as leading to another journey to failure.

Do not rely on just one solution
Just as there is rarely only one contributing factor to disordered eating, there is rarely one simple solution. The forces that fuel binge eating and food addiction are complex.

Recovery is most often successful through a combination of three interventions: (1) nutritional supplementation, (2) medications if needed and (3) lifestyle changes. You can use one or all of these interventions depending on how your body responds.


Our genes provide the blueprints for who we may become; they do not, however, determine who we are. As we learn more about how each person is both unique and extraordinary, we will also be able to provide effective help, because it will be specifically tailored to the individual.