New Study Reveals Surprising Role of Sugar in Human Evolution

For years, scientists have focused on meat and other animal foods when explaining how human brains became bigger. But a new study suggests there may have been another important source of brain fuel: natural sugar and carbohydrates found in foods such as fruit, honey and cooked plants. Researchers from the University of Sydney and the University of Glasgow studied about four million years of human evolution. Their findings, published in Science, suggest that changing diets helped provide the glucose needed by our increasingly energy-hungry brains.

Sweet tooth to big brain: Did sugar help shape human evolution?

How did sugar help the human brain?

The human brain needs a lot of energy, and glucose is its main energy source. As the brains of our ancestors grew larger, their need for energy also increased. The researchers built a model showing how the diets of our ancestors may have changed over millions of years. The earliest human ancestors in the model got more than 65% of their energy from sugars in fruit and other naturally sweet foods. Later, when humans learned to use fire and cook plants, foods such as tubers and grains became easier to digest and provided another source of glucose.

So, it was not simply a case of meat versus sugar. Different foods provided different nutrients and energy. Fruit and honey supplied natural sugars, cooked plants supplied carbohydrates, while meat and other animal foods provided protein and fats.

The researchers suggest that this varied diet, rather than one magical brain-building food, helped support the evolution of the human brain. Their model found that modern humans could get about 25% of their energy from sugars and another 25% from starches, alongside energy from protein and other foods.

From fruit to cooked plants

Early human ancestors lived mainly on plant foods, including fruit. Later, the use of fire changed what they could eat. Cooking made starchy underground foods such as wild yams and other tubers easier to digest. Over time, grains and other starch-rich foods also became important. This means that the story of our growing brains may be much more complicated than simply saying that humans started eating more meat. Animal foods mattered, but carbohydrates may have supplied much of the glucose needed to power growing brains.

FAQs

1. Why does the brain need glucose?

Glucose is the brain’s main source of energy and helps power its many activities.

2. What foods supplied sugar to early humans?

Fruit and honey were important natural sources of sugar.

3. Why was cooking important?

Cooking made starchy foods such as tubers and grains easier to digest, helping provide glucose.

4. Did meat have no role in brain evolution?

No. The study does not say meat was unimportant. Animal foods supplied protein, fats and other nutrients. Researchers suggest that several types of food worked together.