The True Effects of Sugar in Light of Evolution

Sugar has become one of the main “villains” of our time: reducing its content in the diet as much as possible is a priority until it is not naturally present in food. The World Health Organization recommends that intake in the form of free sugars should not exceed 10% of total daily caloric intake in both adults and children, and also suggests reducing caloric intake to below 5% (about 25 grams per day).

It depends on how we perceive them

These free sugars are sugars (refined or unrefined) added to foods and beverages by the manufacturer, cook or consumer, to which must be added those naturally present in honey, syrups, fruit juices and juice concentrates. Therefore, the study of its consumption has been such a hot topic in recent years.

However, many studies still do not take into account the form of ingestion, i.e. whether they are free or internal, which may justify the conflicting data between them. It’s true that experts emphasize the importance of avoiding free sugars, but lack of emphasis in some studies may contribute to the discrepancy in results.

Diana Thomas of the New Jersey Center for Quantitative Obesity Research pointed out this omission. A situation that affects, for example, a test of tolerance to glucose, cholesterol and triglycerides: sometimes there are no changes in these parameters, and sometimes there are.

Given the lack of definition, guidelines in recent decades have also been inconsistent, as they sometimes advise that sugar intake should not exceed 5% of energy requirements, while other recommendations imply that even 25% of total energy can be easily obtained. from this dietary ingredient. There has not yet been a great enlightening study, but viewing this issue through the lens of evolution may give us a clue to the search for truth.

Adapted to fresh fruits

Evolutionary physiology studies how organisms have changed over time to improve their fitness and survival. Their results lead us to believe that evolution genetically adapted the metabolic physiology of our ancestors to work with the internal sugars of fresh fruits, since free sugar did not exist.

During the Miocene era, between 24 and 5 million years ago, fruit was a major component of the hominid diet. According to Italian expert Riccardo Baschetti, four key findings bring an evolutionary perspective to the sugar debate:

• Gastric emptying and own sugars. The speed at which food leaves the stomach is critical to regulating blood sugar levels as it enters the intestines and is absorbed by the body. Glucose and its own sucrose contained in food are excreted in a similar way.

• Evolutionary adaptation to fresh fruit. This results in bowel movements that slow down as glucose concentrations increase. This phenomenon has been shown to fit perfectly with the caloric content of the total sugars present in fresh fruits, which have been the mainstay of human nutrition for millions of years. Evolutionary adaptation suggests that our gastrointestinal system is designed to efficiently manage a wide range of fruit calories, thereby helping to maintain stable blood glucose levels.

• The influence of a large amount of fresh fruit. It was observed that in the range of 0.2 to 1.0 kcal/ml, doubling the volume of glucose intake did not significantly change the rate of emptying. This means that eating large amounts of fresh fruit did not affect glucose homeostasis—the balance and internal stability—of our ancestors, and that human gastrointestinal physiology is adapted to efficiently process even large quantities of fresh fruit without negatively affecting regulation. glucose.

• Unknown free sugars. At caloric concentrations greater than 1.0 kcal/ml, faster delivery of calories to the small intestine is observed. This change occurs just above the highest caloric concentration in fresh fruit, suggesting that free sugars may be considered genetically unknown foods. The advent of agriculture about 10,000 years ago occurred too late at the evolutionary level for the human genome to fully adapt to these changes.

Another new product: salt

We must also take into account the role of salt, the use of which was unknown to our ancestors until about 5,000 years ago. And only since then people began to use it in large quantities to preserve food. However, our physiological systems did not have time to adapt to such an increase in consumption.

Today we know that excess salt is harmful to health. But not only is it a risk factor for hypertension, it also speeds up the absorption of sugars in the intestines, which may explain the link between sugary drinks and type 2 diabetes.

This relationship is driven by the fact that consumption of sugary soft drinks tends to go hand in hand with decreased consumption of vegetables and dairy, naturally low-salt foods, as well as greater consumption of fast food and ultra-processed foods. rich in this seasoning. .

The amount of salt present in ultra-processed foods means that a small portion inevitably passes through the consumption of sugary drinks, unhealthily accelerating the absorption of sugar and contributing to obesity.

In fact, some studies have shown that this link is mediated by salt in the diet, but they have failed to mention the detrimental effect this ingredient has on the absorption of sugars. Links like these give us valuable information about how our food choices can impact our overall health.

Notice to Scientific Mariners

We need to do a study that takes both sugar and salt into account, which is consistent with evolutionary physiology and confirms what many already believe: internal sugar is harmless and free sugar is harmful. As we have already said, Riccardo Baschetti has already set the tone for how to conduct this research. The only thing missing is someone who has a project without a conflict of interest to implement it.