Sugar is the principal nutrient for the cells of our bodies and is, therefore, necessary for life. Despite this, too much sugar emerges as one of the primary challenges to health in modern societies. Sweetness is highly attractive, but sugar is a risk factor for leading causes of death.

The Attraction of Sweetness

The attraction of sweetness is obviously related to the key role of sugar in cellular metabolism. We are attracted to sweet sensations because they are associated with high-energy foods such as ripe fruits and honey. Such foods provide a great deal of energy that fuels cells and may be used to synthesize long-term energy storage in the form of body fat.

Our distant ancestors developed a sweet tooth that favored survival and reproductive success. Of course, they also favored other high-energy foods, particularly meat, that not only offered concentrated energy but also contained many nutrients essential for child growth and development.

Animal foods are typically consumed first in a celebratory meal, ensuring that children and others are well nourished. Sweet desserts usually come last and are perceived by many as the high point of the meal. Coming at the end of the meal, desserts generate satiety due to a rapid rise in blood sugar.

This sugar hit is a key player in the story of modern obesity. Given that obesity is a factor in several leading causes of death, one can appreciate why the health dangers of sugar are under the spotlight for health researchers.

Our species' relationship with sugar was not a problem when sugars came from foods that grew in nature or from honey that was in limited supply. All this changed with the rise of refined sugar, which coincided with the growth of luxury spending and consumerism, in 17th-century Europe.

The Rise of Refined Sugar

Cane sugar has been used for thousands of years, but global supply was limited, making it a luxury product. This changed early in the 16th century when sugar plantations were established in Hispaniola, Cuba, and other Caribbean islands. These plantations used slave labor and satisfied a growing demand for sugar in Europe. A method of extracting sugar from sugar beet was developed in 1747, and this became widely available by around 1800. Corn is a major source of sugar used in food manufacturing, including high-fructose corn syrup, which has received adverse publicity as a factor in obesity.

The big picture is one of increasing availability, and consumption, of cheap refined sugar.

Many fruits, including bananas, figs, and apples, are high in sugar, but eating fruit is not considered a health risk. These natural foods contain fiber, which means that they are processed more slowly by the body and that there is not an intense surge in blood sugar following consumption.

Refined sugar was identified as a health risk if more than 25 grams per day was consumed (which is less than the 39 grams of sugar in a 12 oz can of Coke). Americans average about four times this much, and around two-thirds of the population is obese or overweight.

Sugar and Obesity

When rodents are given sugar water instead of plain water and allowed to drink it freely throughout the day, they consume too many calories and become obese.

The soft drinks industry is, in effect, replicating this experiment on humans, including young people, who often consume heavily sugared sodas. We should not be surprised that we are getting exactly the same results as for the rodent experiments.

Obesity has many other potential causes apart from sugar. One key factor is the relatively low level of physical activity among contemporary children who spend a lot of time in sedentary activities involving screens. Even so, there is one smoking gun implicating sugar. As countries develop, they consume more sodas, and the more soda they drink, the higher their obesity rates. Moreover, the amount of sugar people consume is linked not just to overweight but to many related diseases, known as the metabolic syndrome. These diseases are linked in complex ways to secondary diabetes.

Sugar and Secondary Diabetes

When the diet contains a lot of sugar, it leads to secondary diabetes. This condition is defined by high blood sugar related to reduced sensitivity of insulin receptors. It is associated with obesity as well as many related health problems including high blood pressure, kidney disease, and liver disease.

Secondary diabetes is a tragic outcome of poor diet and exercise habits that are entrenched in modern life. It is a chronic condition and was widely considered incurable. Yet, there is encouraging evidence that behavioral measures, specifically increasing physical activity and adopting a better diet, improve weight regulation and normalize blood sugar.