Sugar: a debate that needs to be settled

Yudkin’s book (and his reputation) dropped in popularity because the evidence he presented was not convincing.

In the last decade, studies have given rise to a revival of the idea excessive sugar intake (or fructose) may contribute to a number of health conditions collectively known under the term “metabolic syndrome.” These conditions include high blood pressure (a precursor to type 2 diabetes), obesity, insulin resistance, and high blood lipids, including cholesterol. The metabolic syndrome is closely linked to heart disease, type 2 diabetes, and other chronic diseases.

Sugar has been in the spotlight recently as a possible driver of obesity.

World Health Organization recommended in 2003 that “free sugars,” or all sugars added to food by the manufacturer, cook, or consumer, should not exceed 10% of the total energy intake. All sugars that are added to food, whether by the consumer, the cook, or the manufacturer. This also includes sugars found in honey, syrups, and fruit juices.

The WHO is updating its recommendations, and a review of the scientific literature was done to determine the effects of sugar on body weight. The results of the study were released last week by the British Medical Journal.

Summary: The authors concluded that increasing sugar consumption among adults was associated with a small but statistically significant (around 0.8 kg) weight gain. In line with this conclusion, a considerable weight loss (and similar) was also associated with a decrease in sugar intake.

Weight gain is linked to sugar consumption. Flickr/demand

Children who consume more sugar also gain weight. Contrary to what was found for adults, a decrease in sugar intake did not have a significant association with reducing body weight among children. This was due to poor compliance, as the children didn’t always stick to their sugar intake levels.

The key conclusion was that the consumption of sugar-sweetened beverages is likely to increase body weight, both in adults and children. This confirms earlier findings that sugar in liquid forms is closely related to weight gain.

Two experts comment on an article that accompanies the BMJ paper.

This form of sugar does not cause satiety in the same way as solid sugar, making it easier to overconsume. Due to this and the high amount of sugar in drinks, it is important to reduce the consumption of sweetened beverages.

BMJ also found that replacing sugars with protein, carbohydrates, or fat did not result in significant weight loss when energy intake was kept constant. The excess consumption of total kilojoules is what leads to weight gain when sugar intake increases. This could be because liquid sugars are less likely than solid sugars to make you feel full.

The authors don’t discount the possibility that weight gain could be due to metabolic effects unique to fructose as hypothesized by Robert Lustig, a US pediatrics professor. ‘s editorial, which accompanies the BMJ article, argues against the “fructose hypotheses” and states that there is “no good evidence” that replacing fructose by glucose would be beneficial.

The editorial points out that “… a number of starchy foods have a higher glycemic indices, which raise blood sugar and insulin faster than the same amount of sucrose.”

It’s not necessary to eliminate sugar from your diet. However, it is important to limit the amount you consume. Flickr/Howey

Does the BMJ article change our understanding of what drives the obesity epidemic in America?

The short answer to this question is no. The paper provides evidence that sugar intakes are harmful to the health.

They also point out that sugar consumption is not the sole cause of obesity, as many people believe. The authors point out that, for instance, the effect of sugar intake on body weight is small, and this is not surprising “owing the multifactor causes of obesity.”

What should we do now that we have this information?

Avoiding excessive intake of sugar would be prudent. However, this recommendation has been made in Australia and other countries since the introduction of dietary guidelines. The relevant Australian policy currently states: “Consume moderate amounts of sugars, and foods that contain added sugars”.

The revised guidelines will likely change this wording when they are published next month. The revised draft guideline currently reads, “Limit consumption of foods and beverages containing added sugars.” Limit sugar-sweetened beverages in particular.