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The Biochemistry of Eating

By Casey Thaler, B.A., NASM-CPT, FNS
February 14, 2019
The Biochemistry of Eating image

When it comes to humans, we’re all just victims of our own biochemistry. Our brains are controlled and ruled by chemicals - from what we eat; to how and when we sleep; even to who we choose as a life partner.[1] Biochemistry - or ‘biological chemistry’ - is concerned with all of the biochemical reactions which take place within our bodies and brains.[2] [3] This means that the simple act of eating a meal is actually composed of thousands of tiny reactions and interactions - on a biochemical level, at least.[4] [5]

Biochemistry is important because it helps us better understand how our bodies work. Biochemistry is most critical to understanding how and what foods to eat and remains a criminally overlooked component of both keeping weight off and maintaining a healthy lifestyle.[6] If we can better understand the reactions happening inside our body, we can better understand how to treat ourselves, overall.

The Biochemistry of our Morning Coffee

To better understand the biochemistry of our eating, it will help to look at how a few individual components of a diet affect our biochemistry. For many (if not all) of us, our day begins with the ingestion of a stimulant. Specifically, caffeine. From our morning cup of coffee onwards, many of us feel most energetic after our first dose of caffeine. This is simple to understand from a biochemical perspective - the caffeine is binding to our adenosine receptors, and simply removing our caffeine withdrawal.[7] [8]

Adenosine helps us stay calm and is even related to sleep.[9] Many do not know this, but caffeine binds to the receptors for adenosine. But this also means that it effectively blocks our body from functioning normally.[10] Our bodies love homeostasis, so if we consume large enough quantities of caffeine on a regular basis, they try to remain in balance by creating more and more adenosine receptors.[11] So - you guessed it - the more caffeine we consume, the more we need just to achieve the same mild ‘high’ we got when we first started drinking coffee.[12] Sadly, this is exactly how all drugs work and caffeine - though legal and widespread - is still a drug, biochemically speaking.[13]

The Enormous Impact of Sugar on our Biochemistry

Another huge element of the biochemistry of our food and drink is sugar. Sugar is definitely a drug. In fact, it’s probably the substance in our diet most obviously associated with drugs.[14] Scientific research has shown that sugar is addictive, it has no nutritional value, and it has hugely negative impacts on our health, especially when it’s consumed in excess.[15] To astute readers - or anyone who has been paying attention - this is not shocking news.

Sugar is fascinating from a biochemistry perspective because there is essentially no reason to consume it - especially in excess - or even in the amounts that we do in a typical western diet. Sugar consumption has gone up ten-fold, in the US and worldwide, since the invention of soda.[16] It is, quite literally, used solely by processed food manufacturers and surreptitiously added to everything (even bread) to make foods more addictive, to get us to crave their products, and buy more of them.[17]

While this sounds like a pretty stark reality, it is nonetheless reality. There is no need for sugar in almost any food. Sugar is only found in good ratios, in food that is organic and made by the earth naturally.[18] If you could only pick one thing to do to improve your healthy biochemistry, lowering or removing sugar from your diet should be it.

In John Yudkin’s classic book Pure, White, and Deadly, he goes over just how bad sugar’s effects are. And the miraculous thing is that he was saying this long before most of us had any concerns at all about too much sugar.[19] If there is one product or industry to blame for decreasing the quality of our diet and decreasing our nation’s health, it would be soda. There is literally no reason for soda to exist. And as Steve Jobs famously said; it’s just sugar water.

When we look at the biochemical makeup up of soda, that is quite literally almost all we find - water, and sugar. Disturbingly, soda is even worse than just this simple formula, as most of the sugar is in the form of fructose, which has been shown, in numerous studies, to have hugely negative impacts on both our liver and overall health.[20] From a biochemical standpoint, fructose is processed differently than glucose and has many disturbing parallels to alcohol in terms of how our bodies and brains are affected by it.[21]

In fact, NAFLD (non-alcoholic fatty liver disease), caused by excess fructose is in many ways the exact same disease as alcoholism.[22] As its name implies, fatty liver disease is usually caused by excess alcohol. However, pediatric endocrinologists are seeing an epidemic in obese children - and they only get this way by excess sugar (specifically fructose) consumption.[23]

So, what does the biochemistry of healthy eating look like? In short, it’s filled with protein, healthy (anti-inflammatory) fats, and complex carbohydrates.[24] These food choices all provide favorable reactions, biochemically, with no real downsides. When we eat a diet like the Paleo Diet® - our bodies and brains remain happy, and function optimally.[25]

Many do not understand that the toll a poor diet takes on us is great. We can lose our ability to process thoughts as quickly, lose our hair, gain weight, develop disease, and even die.[26] And yet many of us still choose to not eat properly. This is truly self-sabotage. By following the Paleo Diet template - all the hard work is done for you. You do not have to think about food choices or worry about the biochemistry of what you are eating. A Paleo Diet is perfectly proportioned to optimize our health, and to keep us lean, healthy, and happy.


[1] Granado-lorencio F, Hernández-alvarez E. Functional Foods and Health Effects: A Nutritional Biochemistry Perspective. Curr Med Chem. 2016;23(26):2929-2957.

[2] Winblad B, Hardy J, Bäckman L, Nilsson LG. Memory function and brain biochemistry in normal aging and in senile dementia. Ann N Y Acad Sci. 1985;444:255-68.

[3] Holden-dye LM, O'connor VM, Stephenson FA. Molecules of the mind: integrating synaptic biochemistry to understand brain function. Biochem Soc Trans. 2006;34(Pt 1):43-4.

[4] Mathes WF, Brownley KA, Mo X, Bulik CM. The biology of binge eating. Appetite. 2009;52(3):545-553.

[5] Imai S, Fukui M, Kajiyama S. Effect of eating vegetables before carbohydrates on glucose excursions in patients with type 2 diabetes. J Clin Biochem Nutr. 2014;54(1):7-11.

[6] Sikaris KA. The clinical biochemistry of obesity. Clin Biochem Rev. 2004;25(3):165-81.

[7] Ammon HP. Biochemical mechanism of caffeine tolerance. Arch Pharm (Weinheim). 1991;324(5):261-7.

[8] Nehlig A, Daval JL, Debry G. Caffeine and the central nervous system: mechanisms of action, biochemical, metabolic and psychostimulant effects. Brain Res Brain Res Rev. 1992;17(2):139-70.

[9] Shryock JC, Belardinelli L. Adenosine and adenosine receptors in the cardiovascular system: biochemistry, physiology, and pharmacology. Am J Cardiol. 1997;79(12A):2-10.

[10] Ribeiro JA, Sebastião AM. Caffeine and adenosine. J Alzheimers Dis. 2010;20 Suppl 1:S3-15.

[11] Urry E, Landolt HP. Adenosine, caffeine, and performance: from cognitive neuroscience of sleep to sleep pharmacogenetics. Curr Top Behav Neurosci. 2015;25:331-66.

[12] Meredith SE, Juliano LM, Hughes JR, Griffiths RR. Caffeine Use Disorder: A Comprehensive Review and Research Agenda. J Caffeine Res. 2013;3(3):114-130.

[13] Pardo lozano R, Alvarez garcía Y, Barral tafalla D, Farré albaladejo M. [Caffeine: a nutrient, a drug or a drug of abuse]. Adicciones. 2007;19(3):225-38.

[14] Avena NM, Rada P, Hoebel BG. Evidence for sugar addiction: behavioral and neurochemical effects of intermittent, excessive sugar intake. Neurosci Biobehav Rev. 2008;32(1):20-39.

[15] Freeman CR, Zehra A, Ramirez V, Wiers CE, Volkow ND, Wang GJ. Impact of sugar on the body, brain, and behavior. Front Biosci (Landmark Ed). 2018;23:2255-2266.

[16] Anjum I, Jaffery SS, Fayyaz M, Wajid A, Ans AH. Sugar Beverages and Dietary Sodas Impact on Brain Health: A Mini Literature Review. Cureus. 2018;10(6):e2756.

[17] Rippe JM, Angelopoulos TJ. Relationship between Added Sugars Consumption and Chronic Disease Risk Factors: Current Understanding. Nutrients. 2016;8(11)

[18] Martínez steele E, Baraldi LG, Louzada ML, Moubarac JC, Mozaffarian D, Monteiro CA. Ultra-processed foods and added sugars in the US diet: evidence from a nationally representative cross-sectional study. BMJ Open. 2016;6(3):e009892.

[19] Yudkin J. Dietetic aspects of atherosclerosis. Angiology. 1966;17(2):127-33.

[20] Rizkalla SW. Health implications of fructose consumption: A review of recent data. Nutr Metab (Lond). 2010;7:82.

[21] Lustig RH. Fructose: it's "alcohol without the buzz". Adv Nutr. 2013;4(2):226-35.

[22] Byrne CD, Targher G. NAFLD: a multisystem disease. J Hepatol. 2015;62(1 Suppl):S47-64.

[23] Basaranoglu M, Basaranoglu G, Bugianesi E. Carbohydrate intake and nonalcoholic fatty liver disease: fructose as a weapon of mass destruction. Hepatobiliary Surg Nutr. 2015;4(2):109-16.

[24] Sauberlich HE. Implications of nutritional status on human biochemistry, physiology, and health. Clin Biochem. 1984;17(2):132-42.

[25] Jönsson T, Granfeldt Y, Ahrén B, et al. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovasc Diabetol. 2009;8:35.

[26] Leslie W, Hankey C. Aging, Nutritional Status and Health. Healthcare (Basel). 2015;3(3):648-58.

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