Obesity studies generate debate on impact of weight, sugar on health

Harvard School of Public Health (HSPH) nutrition experts, including Walter Willett, Frederick John Stare professor of nutrition and epidemiology and chair of the Department of Nutrition, were quoted widely by the media about two obesity studies published in January 2013.

Evidence Grows of Link Between Sugar Consumption and Poor Health

The association between sugar and poor health has been contentious over recent decades, with scientists and industry often sparring about whether or not there’s a link between excessive sugar intake and obesity and higher risk of chronic diseases. But in a January 15, 2013 editorial in the British Medical Journal (BMJ), Willett and David Ludwig, professor in the Department of Nutrition and obesity prevention specialist at Boston Children’s Hospital, citing new findings by New Zealand researchers, wrote that sugar and other refined carbohydrates do play a role in the development of obesity and other health ailments.

The article accompanied a BMJ study by researchers at the University of Otago in New Zealand which showed that reducing sugar intake had a small but significant effect on body weight in adults. The review of 71 studies was commissioned by the World Health Organization, which plans to update its recommendations that sugar intake be limited to 10% of energy intake.

Action should be taken at many levels to reduce sugar consumption and improve the quality of carbohydrate intake, wrote Willett and Ludwig. They suggested strategies such as educational programs, improvements in foods and drinks provided in schools and worksites, and supplemental nutrition programs for people with low incomes.

Efforts to reduce sugar intake should also be part of a broader effort to improve the quality of carbohydrates, including reducing the amounts of refined grain products and potatoes that people eat, the authors wrote. “Reducing the amount of sugar consumed in drinks deserves special attention because of the strength of the evidence and the ease with which excessive sugar is consumed in this form,” they said.

Health Effects of Extra Pounds

Willett and Thomas Frieden, director of the Centers for Disease Control and Prevention (CDC), debated the results of a new obesity study in a Q&A published on January 4, 2013 in USA Today. The study, from researchers at the Centers for Disease Control and Prevention (CDC), reviewed deaths from all causes and body mass index (BMI) levels of people from nearly 100 studies. The findings showed that people who are moderately overweight (up to about 30 pounds above normal weight) had a 6% risk of early death compared with those of normal weight, while those about 60 pounds or more over normal weight, have a 29% greater risk of early death compared with those of normal weight. The study appeared in the January 2, 2013 issue of the Journal of the American Medical Association (JAMA).

Learn more

Ask the Expert: Does Being Overweight Really Decrease Mortality? No! (HSPH Nutrition Source)