8/25/14

How Your Genetics Do and Don't Affect Hunger and Diet

Many people like to grab their gloves and duke it out over the nature or nurture argument. Its one thing to be passionate about an idea, but it’s another to clobber in someone’s face for the sake of conventionalities. And yet, people continue to choose sides on a debate that is no closer to being solved than when it started. Climbing the ranks of this debate is the question of what influences hunger and diet. Some people stay skinny without trying while others keep getting fatter. I’m not one to sit by and enjoy some popcorn, so I’m tossing in my two-cents on this topic.

Dietary habits are influenced by genetic, environmental, and cultural factors. Shafer et al. performed a genome study on dental carries and determined something interesting; genetics plays a role in taste sense. They further determined that an individual’s genetic structure can alter his or her desire or dislike for carbohydrates. This makes a lot of sense when we simply look at the different backgrounds of people. 


EurAsians were humans who lived in the more cold and seasonal areas. Because of this, they would slowly adapt to having a greater desire for carbohydrates. Due to the rarity of natural sugars, the body would have developed triggers to increase the reward of getting them; in other words sweet cravings and sensations will be intensified. EurAsians main diet, however, would have consisted of mainly animal meat, tubers, and greens. Fast forward a few thousand years and their descendants should still have this increased palate for sweets.

However, back in the early days of yore foods were very seasonal. In fact, just a hundred years ago finding fruit during the late winter was an abnormal feat. The summer months grew fruit, and the winter months grew greens. We all know that the earth is seasonal, but did you know that your body is as well? You’ve probably heard of the Circadian rhythm, a 24 hour cycle the body goes through, but humans also go through biorhythms.

A biorhythm is a physical, emotional, or an intellectual cycle that people go through. Each cycle lasts roughly one month (23 days, 28 days, 33 days), and they each can play a significant role in someone’s training or diet. Women go through obvious cycles (menstrual), and even men have been shown to go through hormonal cycles as well. If people can go through biorhythms simply based on hormonal cycles, why wouldn’t they go through seasonal cycles as well?  

The environment can play a huge impact on what we crave. Because our ancestors would have had limited access to natural sugars during the colder seasons, we would have less taste sensitivity for them; thus it would be harder for us to satisfy our sugar cravings. Now you have an excuse for why you can’t stop eating Christmas cookies and pie during the holidays – it’s your ancestors fault.

However, these can’t be the end all answers as to why we fail our diets; because many people who have descended from the same environment have different cravings. A new study of genetics called epigenetics, the study of how the environment affects genetic triggers, could shed some light on hunger. An overview by Christopher Harshaw explains how hunger is first and foremost an “instinct,” however, over time it can be changed. For example, if you’re ancestors passed on a genetic code for you to crave sugar, but your parents fed you a healthy diet without much sugar then you might flip a genetic switch causing you not to crave as much sugar. Likewise, if you have a predisposition to crave sugar and your parents gratified you with twinkies then your body might amp up the craving for sugar; thus making it even harder for you to fight temptations (more excuses to eat Christmas cookies).

So no matter how you look at it, there are a lot of reasons why certain foods are appealing to one group of people and appalling to another. This is also why some people may struggle with dieting while others can hardly polish off a single serving. Can this actually help you stick to your diet? Probably not, but it does give you a glimpse into why it’s harder for you than the fitness model in the magazine.

This draws me back to a point that I bring up a lot, “Quit comparing your success to someone else’s genetics.” All you can do now is buckle down and overcome any stumbling stone standing between you and your goals.
#DOuENDU


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About Me

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BS, MS - exercise Physiology
EPC - Board Certified Exercise Physiologist

Published Thesis
The impact of three different forms of warm up on performance


The Effects of Glucose Supplementation on Barbell Velocity and Fatiguability in Weightlifting - A pilot study"

Graduate from Midwestern State University, founder of Endunamoo Barbell Club, and Endunamoo Strength and Conditioning. Working to help athletes physically reach their goals and achieve scholarships while spiritually pouring into as many people as possible on all platforms.