Asking whether or not we really have free choice is a metaphysical question, perhaps left to those in the movie The Matrix. But throughout our lives,the decisions we make areinfluencedas much bypersonal choices as they are by genetic wiringcreated by millennia ofadaptations.

Consider the simple act of eating. We may think our food consumption isdriven byspur-of-the-moment choices. But the reality is that our individual genetics play a major role in thepleasure we derive from eating. Our physiological response to food (anticipation, selection, consumption, satisfaction) is based in a complicated reward system in the brain involving the mesolimbic network, as well as neurotransmitters such as dopamine. There is a question that stems back to at least the ancient Greeks: Inone version, Hera asked Tiresias, who derived more pleasure from sex, men or women? (Spoiler: Apparently women do 9x more!) Of course its rhetoric, but similarly, we cant assume and shouldnt presume that one persons experience with eating behaviors is the sameas anothers. This could be at the root of why some people find dieting so miserable and difficult, while others find iteffortless.

Do you really consciously choose what you will do?

Why do we think its genes?

Its been established that a series of gene variants is associated with addiction, which is an aberration of the brains reward system, and that these gene variants are heritable (having an alcoholic or other drug addict in the family increases the likelihood that others would be found to have addictive behaviors). More research must be done, butits a good bet that the two (drug cravings and food cravings) are closely linked in the brain.

An interesting look at this issue from a different direction can be found in the workings of the drug Contrave (a combination of bupropion and naltrexone) approved in 2014 for treatment of obesity. Bupropion has shown effectiveness as an appetite suppressant, while naltrexone blocks the effects of opioid drugs removing the reward offered to addicts.

One of the things we learn is thatthere are similarities between drugs and eating at least in terms of the pleasurederived by users. Naltrexone(and the similar naloxone) work through a direct and interesting mechanism: They prevent or reversethe effects of opioids by blocking opioid receptors, thereby preventingthe drugs from having an active site to dock and cause physiological activation.

Many drug overdoses lead to death because of respiratory depression, sedation, and hypotension (low blood pressure). By halting these drug effects, doctors have successfully revivedopioid usersfrom unresponsive states. Naloxonealso can reverse the negative mental and mood effects ofcertain drugs.

In those people using it for weight loss (as a component of Contrave), the drug modifies the response to the pleasure and craving of food in much the same way that it stops drug cravings.The person never feels the high he or she would typically experience fromeating.

Establishing further connection between genetics, brain architecture and food cravings, Contrave has been suggested to work bystimulatingneurons in the hypothalamus to generate theappetite-suppressant effect, whileblocking feedback mechanisms in the brain.

Researchersof Contraves dual mechanism of actionalso suggest that itmight have effects on themesolimbic reward system, adding, that this may lead to further weight reduction by modulating reward values and goal-oriented behaviors.

So certainly which foods we find desirable is in part influenced by our genetics, as well as our life experiences. But how effortful we need to be in our vigilance to avoid or reduce certain trigger foods may have more to do with the neurobiological effects of addiction than we may like to think.

Ben Locwin, PhD, MBA, MS, is a contributor to the Genetic Literacy Project and is an author of a wide variety of scientific articles in books and magazines. He is an expert contact for the American Associationof Pharmaceutical Scientists(AAPS), a committee member of the American Statistical Association (ASA), and has been featured by the CDC, the Associated Press, The Wall Street Journal, Forbes, and other media outlets. Follow him at@BenLocwin

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Overeating? As with drug use, genetics may drive our choices - Genetic Literacy Project