Genetics – How They Should Shape Your Diet

By Shane YoungJune 13, 2017


Homo sapiens have evolved over millions of years to bring us to where we are today, upright, fairly intelligent and increasingly aware of our bodies and how to best look after them.

As with all organisms, our evolution is written into our genome. A genome being the complete set of genetic instructions of any organism, in our case homo sapiens, that shows the evolutionary path that has lead us to where we are now. The way our genome looks today has been shaped by the many genetic changes our ancestors have been faced with. Not all of our ancestors lived in the same climate or faced the same environmental challenges or advantages as each other. Some survived barren landscapes and scorching heat, others icy tundras and sub-zero temperatures, whilst others evolved living within lush, tropical climates.

Because of this, it stands to reason that we are not all genetically equal when it comes to evolution, and more specifically how we have adapted in relation to our diet. Evidence suggests that when it comes to the modern diet, we as a species have strayed away from what our bodies can handle, faster than our bodies have been able to adapt.

As Robb Wolf says; “ Research in biology, biochemistry, Ophthalmology, Dermatology and many other disciplines indicate it is our modern diet, full of refined foods, trans fats and sugar, that is at the root of degenerative diseases such as obesity, cancer, diabetes, heart disease, Parkinson’s, Alzheimer’s, depression and infertility.” For this reason, resorting back to a more simplified diet, that avoids processed foods, as well as excess carbohydrates, and instead, focuses on foods that have been available to us over the span of our evolution, is in our health’s best interest.

This is where the benefits of the paleo diet comes into play.

The paleo diet is based on genetics and takes into consideration that human beings are genetically wired to environmental factors that are quite different from that of today. Evolution is a slow process and the human race has seen such rapid advancements in technology over the past few hundred years, that we have not been able to genetically adapt to the changes these advancements have made to our ‘modern diet’.

Yet, as I mentioned briefly before, there is another consideration to be taken into account when determining what works best for you personally, and not just for humans as a species. Your genetic background. Studies indicate that people from different historical backgrounds may be more or less suited to specific nutrients, depending on their genetic make-up.

For the sake of this blog, I would like to focus on carbohydrates, and more specifically on starch and lactose, and how genetics play a leading role in your ability to digest them.

Lactose and the LTC gene

Lactose, a disaccharide sugar compound found in milk, requires the enzyme ‘lactase’ in order to be digested by the human body. When we are young, the lactase enzyme is more prevalent in our body, so that we are able to digest our mother’s milk, yet as we grow into adulthood, our levels of this lactase enzyme drop significantly. In fact, many people lose the ability to produce lactase altogether. The production of lactase is controlled by the LCT gene and for many people their LCT gene shuts down as they enter adulthood, causing them to become lactose sensitive or intolerant. This is the divide between lactose tolerant and lactose intolerant people.

As stated in a study by Deng Y, Misselwitz B, Dai N, and Fox M in 2015, ‘Lactose Intolerance in Adults: Biological Mechanism and Dietary Management’, “The percentage of the population that has a decrease in lactase as they age is less that 10% in Northern Europe and as high as 95% in parts of Asia and Africa”

So what this means for American’s is that if your family are American dating back many generations, then chances are you may have a dairy intolerance.

Carbohydrates and the AMY2 gene

The AMY2 gene is an interesting gene because it plays an important role in the digestion of starches. Studies suggest that obesity may be genetically linked to people’s ability to digest carbohydrates. How well you digest carbohydrates is directly linked to the number of AMY2 genes you carry. Though the range can fall between 2 and 15, most people carry between 4 and 8. How many AMY2 genes you carry depends on your ancestors and from what part of the globe they originated. Those from drier climates have better adapted to eating foods higher in starches, whilst those from lush and dense climates are more likely less tolerant, as their ancestor’s diet contained less starch.

Because of this, your genetics plays a role not only on your tolerance towards carbohydrates, but also on your ability to metabolize it correctly and avoid putting on excess weight.

Even though evidence suggests that our evolution did not cease to progress since the Paleolithic era, it does indicate that the majority of us are not fortunate enough to have all the genetic adaptations that make us able to effectively digests lactose or starches. As Kriss Cresser says in one of his articles in the Daily Beast, “Two-thirds of the population still cannot digest lactose as adults, and nearly one in 10 people are intolerant to gluten.”

For this reason, and the numerous other health benefits that can be gained from it regarding health and maintaining a healthy weight, the Paleo diet really is the diet that our DNA dictates!

In health,



*About Ascend Body: As the best personal trainers in San Francisco’s Mission District, we offer 1:1 personal training, Semi-Private strength training sessions and Boost your body small group training sessions. We pride ourselves on having the best nutritionist, massage therapists and wellness coaches in SF to provide you a one stop shop for all your SF fitness and wellness needs. Call (415) 724-7164 to schedule a free nutrition and fitness consultation today!


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