Man has always lived under the threat of food insecurity and therefore the brain is wired to gorge and hoard in times of plenty. The calorie dense foods in traditional societies were meat, honey and fruits but were not easily available. Glucose and fructose exist freely as natural sugar in fruits but unlike tubers which are available year-round, fruits are seasonal and cannot be stored. That brings me to glucose, the primary nutrient used by all cells but let me digress a bit: About two percent of earth’s water is frozen up in glaciers/ice caps, a whopping 97 percent exists as salty ocean water, and less than one percent fresh water is available for drinking. This perfectly fits the saying: “water, water everywhere and not a drop to drink”.
The question is what has this got to do with glucose? Like water, glucose molecule is the most abundant simple sugar and the building block for woods and plant stems as cellulose. A typical forest is therefore an “ocean” of glucose molecules “knitted” firmly in woods and living plant stems. Yet, despite its abundance, humans can only extract glucose from edible carbohydrates such as tubers which are year-round and from fruits in Summer or rainy season. Therefore, for several generations, before mechanized farming, glucose was everywhere but like fresh water it was very scarce.
Given the natural history of glucose scarcity, human physiology and survival depended on raising blood glucose as opposed to lowering it as we currently do in modern obesogenic environments with high rate of diabetes prevalence. In fact, there are several hormones collectively called glucogenic or counterregulatory hormones that help to release glucose into the bloodstream during foraging, fasting and sleeping. It is therefore no surprise that only one hormone, called insulin, is responsible for lowering blood glucose which was infrequently secreted during occasional consumption of carbohydrate meals in austere times. However, in modern times, there is no such thing as “glucose desert” as we joyfully swim in the “ocean” of man-made sugar with no need for the next fruit harvest.
Sugar is now cleverly produced from corn starch, a grain product, by using enzymes to rearrange the shape of glucose to make a mix of free glucose and fructose, called high corn fructose syrup, similar to honey and fruits. It should be noted that glucose is not particularly sweet but the fructose part of the glucose/fructose combo is the sweet sibling that drives the propensity for overeating. Therefore, think corn, the next time you see ice cream, brightly colored soda drinks, snacks, salad dressings, ketchup, etc. We can also raise weighty and fatty grass-fed corn finished beef in no time. We have therefore successfully been able to meet the two macronutrients (fat and sugar) and non-calorie salt that hyper-stimulate our energy hogging brain to overeat even against our goal to keep a slim body.
The food industry, a behemoth 8 trillion dollars in 2021, is taking advantage of the brain’s propensity to seek high dense calories by providing palatable and processed foods that contain sugar, fat, and salt. The efficient food seeking behavior still rules and the modern traditional societies have not been observed to purposely set out to collect vegetables and have not been noted to have a salad menu. According to Guyenet in The Hungry Brain: “It doesn’t make a lot of sense to burn 200 Calories collecting 50 Calories’ worth of salad.” As all mothers know so well, this is the reason why toddlers do not get excited about broccoli, asparagus, and other vegetables as the brain places value on calorie dense foods and not so much on vitamins and minerals found in these plant foods.
Guyenet also observed that while you would obligatorily eat plain boiled yams or potatoes with no salts or butter when hungry, you need not feel hungry to eat potato chips or ice cream and definitely won’t feel too full for a dessert and don’t need to be thirsty to have a soda bottle on your work desk. In case you feel the temptations for dense calories are all on you, all hunter gatherers have been reported to be gluttonous on a few lucky occasions of honey harvest or big kills. They have been reported to “drink honey like a glass of milk” and “if they kill large animal…they cut off the fattest parts, boil it down, and drink the soup”.
As someone who grew up in rural Nigeria with no fruit juice, no ice cream and who can still play the “video” scene of tasting coca cola for the very first time at age 12, I have witnessed a spectacular growth in the last 6-10 years: My family was the third or fourth to move into our outskirt subdivision or estate about 22 years ago. We were 3 miles away from town with practically no commercial life. Presently, a half-mile walk from my house to the gate boasts of more than 9 restaurants, including a 24-hour donut shop, and I am writing this in a coffee shop alongside the road where there was literally nothing not so long ago.
These exposure to dense calorie foods is multiplied all over western world and urban centers of developing countries. While I did not miss or tempted with the so-called junk food growing up, it is essentially up to me to spend two or three dollars at the donut shop at my subdivision’s gate. Again as noted by Guyenet, a neurobiologist, my quick irrational nonconscious behavior would remind me that $3 spent on donuts now would not affect my Mortgage payment at the end of the month and would try to override my slow conscious rational thought process about abstract weight gain and health issues in my future.
Are we helplessly doomed to the lifestyle of chronic overconsumption? Of course not! We are still capable of avoiding the food triggers and able to walk away. While this appears simplistic, the fact remains that successful people had the choice of nonconscious behavior of a layback life or consciously working off their hides to reach their lifetime goals. Food choices are no different in a practical sense, but each society and individuals must work out the tough paths based on different environments.
As a proverb in my Yoruba language says: You can’t go to bed with fire on the roof. Fats and carbohydrates have common metabolic pathways and the ultimate chemical energy from carbohydrates and fats is no different. The diet argument without understanding the powerful influence of the brain on food intake is like going to bed with fire on the roof. All behaviors, including consumptions, involve the brain and it does not matter the kind of diet or the source of the calorie, at the end of the day, “the dose makes the poison”. Maybe a reason for the increasing prevalence of global obesity.
Mukaila Kareem, a doctor of physiotherapy and physical activity advocate, writes from the USA and can be reached through firstname.lastname@example.org