Have a sweet tooth? Blame brain evolution

By Alexandra Latremouille

A biopsychology student at the University of Michigan has said evolutionary brain patterns make refined sugars desirable, even though the body cannot metabolize them well.

Even though Halloween is over, these brain patterns are making Canadians consume more sugar than they should. Why? Historically, people ate sugar-dense foods because they provided energy and enlarged fat reserves during famines. Over thousands of years, the association between sugar and survival created mental reward systems in humans, making them crave it frequently.

This reward system exists because sugar increases serotonin levels in the brain. The release of this chemical stimulates the dopamine receptor D2, according to the student, Vikrant Garg.

“These receptors tell us that these high-calorie energy foods are good for us,” said Garg. “They tell the brain to look for them more and more.”

American physician Mark Hyman found some people have fewer D2 receptors than others. This causes them to require more stimulation, prompting increased sugar consumption. These people are then more susceptible to problems such as obesity and Type 2 diabetes.

The modern abundance of processed sugars, which contain fructose and little fibre, also contributes to these issues. Fructose, a simple sugar found in plants, can only be metabolized by the liver. When overloaded, it turns the fructose into fat. It is unknown how long it will take for the liver to evolve to metabolize it better, according to Garg.

“The best answer is that it’s hard for me to say,” said Garg. “It’s important to note that a lot of this research also isn’t done on humans, so even if they do find evolutionary changes in rats, those same evolutionary traits may take much longer to show up in humans, if at all.”

Regardless, these issues can be avoided with subtle lifestyle changes. A local physical therapist and holistic health enthusiast said one way is to consume different types of sweeteners.

“Not all sugars are created equal,” said Jesse Chappus, who works at DJC Integrative Therapy. “There’s stevia, which comes from a leaf, xylitol, coming from birch trees. You know, these don’t have the same negative effects on the body. People should be aware alternatives exist.”

Unlike refines sugars, stevia and xylitol moderate insulin levels and improve dental health, respectively. Stevia also acts as an appetite suppressant.

Cravings can also be reduced by taking natural supplements, according to Ohio State University professor Jeff Volek. For example, by moderating blood sugar, chromium picolinate lowers people’s drive to eat unhealthy food. A 600 microgram dose over the span of eight weeks is particularly effective, according to Volek.

Chappus said small changes like these are among the most important steps in altering sugar addiction.

“This sort of addiction can happen to anybody,” said Chappus. “This problem is happening on a chemical level and it will take time to break that addiction. But over time your cravings will change if you start making healthier choices.”

He and Garg said it is unwise to simply wait for evolution to make sugar-laden lifestyles sustainable.

“This would take lifetimes and lifetimes,” said Chappus.