Put simply, sugar is a crystalline carbohydrate that makes foods taste sweet. There are many different types of sugar, including glucose, fructose, lactose, maltose, and sucrose - also known as table sugar.
Some of these sugars, such as glucose, fructose, and lactose, occur naturally in fruits, vegetables, and other foods. But many of the foods we consume contain "added" sugars - sugar that we add to a product ourselves to enhance the flavor or sugar that has been added to a product by a manufacturer.
The most common sources of added sugars include soft drinks, cakes, pies, chocolate, fruit drinks, and desserts. Just a single can of cola can contain up to 7 tsps of added sugar, while an average-sized chocolate bar can contain up to 6 tsps.
Perhaps most strongly, added sugars have been associated with the significant increase in obesity. In the US, more than a third of adults are obese, while the rate of childhood obesity has more than doubled in children and quadrupled in adolescents over the past 30 years.
A 2013 study published in The American Journal of Clinical Nutrition suggested that consumption of sugar-sweetened beverages increases weight gain in both children and adults, while a review paper from the World Health Organization (WHO) notes an increase in the consumption of such beverages correlates with the increase in obesity.
Are we becoming addicted to sugar?
In support of these associations are Dr. Robert Lustig, a pediatric endocrinologist at the University of California-San Francisco and author of the book Fat Chance: The Hidden Truth About Sugar, who claims sugar is a "toxic" substance that we are becoming addicted to.
A 2008 study by researchers from Princeton University, NJ, found rats used to consuming a high-sugar diet displayed signs of binging, craving and withdrawal when their sugar intake was reduced.
"We need to wean ourselves off. We need to de-sweeten our lives. We need to make sugar a treat, not a diet staple," Dr. Lustig told The Guardian in 2013.
"The food industry has made it into a diet staple because they know when they do you buy more," he added. "This is their hook. If some unscrupulous cereal manufacturer went out and placed your breakfast cereal with morphine to get you to buy more, what would you think of that? They do it with sugar instead."
In her popular blog, Goop, Gwyneth Paltrow cites sugar addiction as one of the reasons she decided to quit sugar completely.
"The bottom line is that sugar works the addiction and reward pathways in the brain in much the same way as many illegal drugs," she writes. "Sugar is basically a socially acceptable, legal, recreational drug with deadly consequences."
Is eliminating sugar from our diet healthy?
The array of studies reporting the negative implications of added sugar led to WHO making a proposal to revise their added sugar recommendations in 2014. The organization issued a draft guideline stating they would like to have their recommended daily free sugar intake from 10 per cent to 5 per cent.
"The objective of this guideline is to provide recommendations on the consumption of free sugars to reduce the risk of noncommunicable diseases in adults and children," WHO explained, "with a particular focus on the prevention and control of weight gain and dental caries."
In addition, it seems many health experts, nutritionists and even celebrities like Gwyneth have jumped on a "no sugar" bandwagon. But is it even possible to completely eliminate sugar from a diet? And is it safe?
Biochemist Leah Fitzsimmons, of the University of Birmingham in the UK, told The Daily Mail:
"Cutting all sugar from your diet would be very difficult to achieve. Fruits, vegetables, dairy products and dairy replacements, eggs, alcohol, and nuts all contain sugar, which would leave you with little other than meat and fats to eat - definitely not very healthy."
The study, published in the journal Nature, suggests artificial sweeteners - including saccharin, sucralose, and aspartame - interfere with gut bacteria, increasing the activity of pathways associated with obesity and diabetes.
What is more, they found long-term consumption of artificial sweeteners was associated with increased weight, abdominal obesity, higher fasting blood glucose levels and increased glycosylated hemoglobin levels.
"Together with other major shifts that occurred in human nutrition, this increase in artificial sweetener consumption coincides with the dramatic increase in the obesity and diabetes epidemics," the authors note. "Our findings suggest that artificial sweeteners may have directly contributed to enhancing the exact epidemic that they themselves were intended to fight."
